alternative energy sources research paper

IEEE Account

• Change Username/Password
• Update Address

Purchase Details

• Payment Options
• Order History
• View Purchased Documents

Profile Information

• Communications Preferences
• Profession and Education
• Technical Interests
• US & Canada: +1 800 678 4333
• Worldwide: +1 732 981 0060
• Contact & Support
• About IEEE Xplore
• Accessibility
• Terms of Use
• Nondiscrimination Policy
• Privacy & Opting Out of Cookies

A not-for-profit organization, IEEE is the world's largest technical professional organization dedicated to advancing technology for the benefit of humanity. © Copyright 2024 IEEE - All rights reserved. Use of this web site signifies your agreement to the terms and conditions.

• Open access
• Published: 23 February 2021

A critical review of the integration of renewable energy sources with various technologies

• Erdiwansyah   ORCID: orcid.org/0000-0001-8887-8755 1 , 2 ,
• Mahidin 3 ,
• H. Husin 3 ,
• Nasaruddin 4 ,
• M. Zaki 3 &
• Muhibbuddin 5  

Protection and Control of Modern Power Systems volume  6 , Article number:  3 ( 2021 ) Cite this article

25k Accesses

190 Citations

Metrics details

Wind power, solar power and water power are technologies that can be used as the main sources of renewable energy so that the target of decarbonisation in the energy sector can be achieved. However, when compared with conventional power plants, they have a significant difference. The share of renewable energy has made a difference and posed various challenges, especially in the power generation system. The reliability of the power system can achieve the decarbonization target but this objective often collides with several challenges and failures, such that they make achievement of the target very vulnerable, Even so, the challenges and technological solutions are still very rarely discussed in the literature. This study carried out specific investigations on various technological solutions and challenges, especially in the power system domain. The results of the review of the solution matrix and the interrelated technological challenges are the most important parts to be developed in the future. Developing a matrix with various renewable technology solutions can help solve RE challenges. The potential of the developed technological solutions is expected to be able to help and prioritize them especially cost-effective energy. In addition, technology solutions that are identified in groups can help reduce certain challenges. The categories developed in this study are used to assist in determining the specific needs and increasing transparency of the renewable energy integration process in the future.

1 Introduction

Decentralization in the electricity sector is a major step in the spread of renewable energy sources that can reduce dependence on fossil fuels [ 56 ]. Global growth of photovoltaics (PV) and wind power in recent years has been 4% and 7%, respectively. The average increase over the past 5 years reached 27% PV and 13% wind [ 37 , 80 , 109 , 116 ]. Variable renewable energy (VRE) has differences, in various ways, from conventional generation. There are six main characteristics of VRE generator output, such as: the main resource has variable, small and modular VRE generators, which are different from conventional generators and are non-synchronous and an unpredictable type of VRE, although there may be low costs in the short-term [ 5 , 50 , 59 ]. These characteristics can create various challenges to the existing power system. In this case, power system performance characteristics can be affected because of some predefined challenges, e.g. the capacity for transmission line loss or inadequate generation. In addition, the inability of portfolio generation available for matching the demand for power to the needs at any time [ 11 , 31 , 39 , 40 , 63 , 88 , 113 , 129 ].

Existing energy technologies can be used to overcome these challenges. In this case, modification technology and renewable technology can reduce some of the effects, such as the expansion of transmission networks and centralized or distributed storage devices. Integration of VREs connected to power systems requires technological solutions to achieve the decarbonization target. However, the application of a technology can cause complications caused by three main factors. First, technology choices include the implicit or explicit application of the costs, and the maturity and technological preferences of policymakers as well as companies [ 46 , 90 , 95 , 115 ]. Second, the decision on a specific solution technology is not via a single entity but rather several actors, such as utilities, system operators and regulators [ 57 , 66 , 94 , 124 ]. Finally, designated technologies vary by region including the VRE share of generator portfolios or individual power configurations for interconnected island systems [ 21 , 69 , 82 ].

From the opinions of several practitioners and researchers on energy transition, we can say that there is not enough transparency on the scope of the technologies to overcome these challenges [ 53 , 60 , 75 ]. The individual analysis offered by some proposes specific technologies, e.g. voltage management solutions for networks distributed through VRE penetration [ 70 , 77 , 98 , 131 ]. However, there are several technologies presented in this paper that have the potential to overcome broader challenges such as battery storage. In addition, scenarios for investigating the deployment of specific technologies to increase storage and transmission capacity have also been discussed [ 33 , 49 , 101 ]. However, from several studies, the substitution effects of different technology solutions are very rarely considered. Other studies focus only on some aggregate challenges, especially the challenges of flexibility [ 10 , 74 , 81 , 84 , 110 , 118 ]. However, challenges are defined at an aggregate level such that they do not necessarily lead to a particular solution technology. While some technology solutions and individual challenges might be known, some of the available literature does not provide a transparent picture. It is very important that decision-makers and researchers alike are aware of these factors when considering energy transition. When so informed, they will be better able to determine the road map and strategy on technology for the development of power system plants.

Renewable energy technology is widely covered in the literature and clearly various challenges still exist. The review carried out in this study aims to map the challenges of VRE by describing what technology solutions are appropriate to overcome these challenges. The approach taken in this paper is the analysis of data from the literature used to compile and map the list of technology solutions and challenges based on their interrelations, and to identify any lack of consistency and classify challenges to VRE. This approach aims to distinguish the observed symptoms, e.g. performance characteristics that change. Furthermore, this analysis is complemented with information from several experts to strengthen and ensure more accurate results. The findings on challenges and their linkages to technology solutions are also discussed. The relevant implications for policymakers and companies are presented in the next section. The main contribution of this review is to provide up-to-date information and useful knowledge in the deployment of RET so that energy access across the country can be improved. The systemic approach within an RE framework for information on important components of the RE ecosystem is a feature of this article.

The outline of this paper is as follows. Part one is an overview. Part two describes the materials and methods used. Part three gives the results and discusses the review and analysis regarding RET. Part three presents the findings and solutions of RET in detail. The final part is the conclusion.

2 Materials and methodology

2.1 collecting challenges and technology solutions.

Analysis of the challenges and technological solutions contained in this study were collected from literature published in journals, conferences and from some institutions in the English language. The samples analysed in this paper were mostly collected from internationally recognized journals and sources from established publishers such as Elsevier (Science Direct), Springer, Wiley, etc. [ 13 , 38 , 117 ] and from various online websites published by several official government and private institutions and research institutions. The journals analysed and reviewed in this paper contained 132 articles deemed relevant to technological challenges and solutions, especially for renewable energy.

The literature review conducted in this paper is divided into several categories to map various technological challenges and solutions comprehensively. The first category reviewed related to challenges and technological solutions from a systemic viewpoint, looking at the differences between systematic studies that focus specifically on technological solutions and challenges as well as other foci relating to VRE in an integrated manner in certain areas such as islands or villages. Reviews relating to market share issues or regulations are set in perspective from a technological or operational solution integrated directly with VRE. The final category analysed is the basis for extracting technological solutions and challenges. Studies relating to perspective technology and operations are used to eliminate ambiguity for the identification of challenges. This is due to dependence on fundamental technical phenomena. Various sequential effects in increasing the yield of VRE penetration have been reported in several studies [ 35 , 71 , 97 , 120 ]. This is done because it does not have the marginal cost that is important to the challenges of integrating renewable energy. However, the ambiguity of challenge that is defined on the economic perspective has a lower spot price so that it is following the wishes of the community in perspective. To define various technical challenges including generation, it is inadequate to adjust ambiguity because it has potential effects that are not desired by stakeholders. For example, the selection of problems, in particular, is not an institutional or organizational challenge. As such, it is very easy to overlook storage from a technical point of view. Organizations or institutions that have changed are in fact steps for technical reconfiguration. In addition, it can increase more than one market share for technology solutions to power systems.

Integration of challenges and technological solutions collected and analysed from a variety of literature is a function as well as interview input for further research processes. This challenge is not tangible, in this case, the description and the words conveyed have differences. First, the challenges are collected in a long form, then iteratively collected and repeated. The technological solutions collected are determined with two requirements, first; independently this technology must be able to mitigate one another and automatically the challenges are integrated directly into VRE. Such requirements are very necessary to prevent the grouping of sub-technologies used as technological solutions. One example of sub-technology is Smart Meter, which is very possible to respond to requests as needed. However, it cannot independently reduce challenges that are integrated directly with VRE. Therefore, it is important to classify responses to requests for technological solutions, however, not for Smart Meters. As for the second category, it is done to define technology solutions based on their respective functions as explained by [ 16 , 76 , 93 ]. Thus, the exclusion of technological solutions can gradually be helped by the differences between one another. Given the example of the request-response, the main function of this technology is to reduce power at certain times and devices. However, response requests are operated on different devices, for example, electric heaters and heat pumps so that different technological solutions cannot serve similar functions. This study develops the challenges and technological solutions based on the various literature reviewed. The identification of all interrelated technological solutions is described with specific challenges.

The list of challenges as explained earlier will be refined with literature and reviews relating to challenges according to their level and challenges related to overall causality (Table 1 ). The relationship between the challenges and the technological solutions analysed shows that the two are mutually exclusive. Therefore, the analysis methodology applied in this study aims to find out the causes, management tools and the standard tools. Besides, the purpose of applying this method is to identify the main causes of certain problems and events as the root causes [ 14 , 36 , 112 ]. Categories with failure modes on micro-networks that can be used to find various errors and resolutions are found in the method [ 34 , 48 , 52 ]. The method is applied to identify the increasing symptoms of penetration of VRE collected from various literature. The symptoms analysed represent various effects that have adverse effects on performance characteristics for the power system. The identification of challenges found in the literature is then mapped based on the symptoms of each specific VRE characteristic that is the root of the problem.

3 Result and discussion

3.1 defiance.

There are eight categories of problems in increasing VRE penetration found in some of the literature as shown in Table 2 . Furthermore, the problems that have been identified were divided into four main categories as requirements for basic performance for power systems. The dominant performance requirement for end consumers is one of sufficient power quality. This power quality consists of a continuous and uninterruptible power supply with a steady-state of voltage and current. In addition, if there is an instant matching, it is better to stay awake and safe. The basic category of VRE can be responsible for power quality challenges that include the modularity of the VRE generator and the fact of dissonance. Furthermore, the flow was categorized as transmission and distributed power efficiency. Multiple stream categories were the cause of the challenge compared to the other categories. Modularity, location constraints and VRE were the biggest part of the flow of challenges. The frequency of controls and challenges was categorized as stability to the power system to restore the system after a blackout. The cause of the stability of this challenge was due to the modularity of the VRE generator and the synchronization of the generator. The relationship between the challenges with the balance of supply and demand for active power in the short and long term of the system was categorized into power balance. This included a wider coordination system of speed capacity in the power system to the generator and ramp to a minimum. The main cause of the challenges was the uncertainty and variability of VRE. The main problem from the results of the analysis has given a bottom-up challenge category that was consistent by adjusting the problems contained in the power system to increase VRE penetration. A detailed review of the interrelated challenges between VRE characteristics and challenges is the basis of the review in this paper.

The results of the analysis of the main problems contained in an electricity network problem that includes a mismatch of demand and electricity supply are shown in Fig.  1 . Schematic description of the analysed problem was categorized into five chains, i.e. the causal effects of different VRE characteristics. Further analysis was carried out to ascertain the level of detail of each so that the problem can be resolved as quickly as possible before the selection of challenges interrelation analysis. Demand and supply that do not have in common certainly have a variety of different reasons besides increasing VRE penetration. For example, delivery limitation from nuclear power plants and coal is one of the reasons because the power system is less flexible [ 74 ]. However, the main focus of this paper discusses the challenges and integrated technological solutions and causes of the connection to the increased VRE penetration. The main problems analysed are eight causes caused by the increased VRE penetration as summarized in Fig. 1 . A list of the challenges that has been summarized includes descriptions and categories of each as well as the symptoms observed and references as shown in Table  3 . Twenty six challenges have been identified as a whole and most of them are challenges related to power system stability and power flow.

Analysing the root cause to balance challenges

3.2 Technologies of Solutions

Categorical and technological solutions and challenges are generally not specifically available in the literature. This is because most categories are implicit and have differences in the focus of each research. The study of power systems are flexible such as technology that can consume and produce power actively [ 25 , 97 ]. Meanwhile, research on electricity networks tends to focus on technology for power distribution and transmission only ([ 99 , 100 ]. Technology solutions that are comprehensively registered are not included in the technology identification as reported in the study [ 63 ]. Categorization of technology solutions is determined such as transformation in the energy sector and conclusions with a higher level. Research on top-line classification using two characteristics assigned to technological solutions has been reported by [ 54 ]. Transformations in the energy sector that lead to distributed or centralized systems are characteristics as reflected in the literature [ 19 , 22 , 26 ]. Therefore, the difference between distributed and centralized technology solutions can be used at a higher or lower level of system challenge. Technology with one side of generation and transmitted technology that is distributed with the other side can be categorized into the second as reported in several kinds of literature. Technology flexibility can be classified as technological solutions such as technology that contributes to system flexibility producing or consuming active power or better known as grid technology that is also classified as a technological solution. The characteristics of technological solutions can be divided into four groups through two assignments. The group which is categorized as two assignments includes a description, e.g. potential applications and solutions for each technology solution as shown in Table  4 . Twenty one technology solutions have been identified; 10 of which are distributed technology solutions, while the remaining 11 technological solutions are centralized. Besides, 21 technological solutions are also distinguished from the flexibility and grid technology systems. Whereas, there are 8 flexibility technologies and 13 grid technologies.

Grid technology is considered more attractive than flexibility technology because grid technology can serve both centralized and distributed systems. An estimation solution in a grid distribution system can estimate or measure a particular grid area. While responding to requests to serve multiple applications can be done with technology flexibility. Centrally distributed and distributed technology systems are very similar when they were first seen. However, more closely, the design between the two shows the difference. Where the ability to serve the application is distinguished from the operator and the owner himself. This difference is illustrated in the case of a stored and distributed system. On the other hand, storage with a distributed system is generally a battery unit installed at the household level with a closed state. Optimized independent consumption of these units is generally found in households, e.g. end consumers or stand-alone. While centralized storage systems such as water pump storage units or batteries are connected. The purpose of this application is for a short period during peak periods or to maintain the system’s power stability. Whereas centralized distributed storage is generally found in the operator or utility system.

3.3 Interrelationships between solutions to challenges

After completing the identification of technological solutions and challenges for integrated VRE, an analysis was carried to overcome the challenges as shown in Table  5 . Challenges contained in the scope of solutions can ignore the number of technological solutions so that defined challenges can be addressed. Successful solution spaces are identified as illustrated in Table  6 . Where the potential solutions contained in technological solutions that refer to several challenges can be addressed as quickly as possible. Because the space and potential of qualitative solutions are numerical comparisons and very limited to be used. Observation matrices made from the perspective of solutions such as high potential solutions and overall challenges are technological flexibility. VRE generators and distributed conventional generators that have a high level of potential solutions are included in the flexibility technology group, for example, large conventional generators with low potential solutions and conventional generation. Furthermore, distributed technological solutions tend to be higher compared to centralized systems. However, distributed grid technology has special exceptions especially for limiter or harmonic filter devices. Finally, the unique value that grid technology has on specific challenges include direct current control systems that have high voltage (HVDC) and power flow that can accurately solve problems such as long transmission distances. However, these challenges can generally be addressed by utilizing flexible technology.

Contributions made by the solution technology to solve the challenges are described in Tables  5 and 6 . Challenges that are local and site-specific have a narrower scope because the solution can only be done by the distributed solution technology, modified distributed VRE generators or additional technology solutions, e.g. harmonic filter. The whole technology group can solve various flow challenges, except technology-centred flexibility that has limitations in solving flow problems. The difference in solution space is included in the category of flow challenges starting from a narrow space to a wider space. The challenge of stability can be solved by a system technology solution by controlling at the system level centrally. Thus, the challenges of flow and distributed technology networks cannot solve challenges to stability, unless the system level can be aggregated. Stability categories such as challenges have wider solution space; however, systems in control interactions cannot be improved. To be able to balance, challenges can only be done by flexibility technology so that existing challenges can be tailored to the needs and active power consumption, excerpt for the increase in the more important VRE estimates. In general, the challenges in the balance category have a wider solution space than the availability of generations in the long run.

Three insights are very important in integrating VRE and decarbonization for the energy sector. The first process discusses two insights for overcoming integrated VRE challenges, e.g. a different power system. The last insight illustrates the results of research that can improve policymaking in the energy sector transition. Solution space for different challenges is the first point, while earlier observations are made for several types of technology that can solve specific challenges. However, the intuitive analysis of the results of expert interviews shows that business people and policymakers are not very familiar with the technological solutions that can be used to solve certain challenges. It is very clear that this technology falls into different categories. However, the development of different solution technologies can reduce the economic viability of a single technology and diminish market potential. Contributions in the decline in market price levels have a relationship with the things mentioned above. This is the same as the balancing power market in Germany. In this case, storage institutional frameworks, increasing VRE forecasts, changing demand responses simultaneously can significantly reduce market prices [ 43 , 51 , 87 ].

An illustration of the balance and challenges of stability can be used further as an example. The results of the interviews with experts clearly show that each different technology category can function as technology e.g. request responses available only focus on a centralized solution. Therefore, large scale and conventional generation are competitive technologies. However, the distribution of technological flexibility is not focused on analysing the more competitive technological landscape. This can be said as a prominent relationship to the potential influence of grid technology on technology flexibility, e.g. VRE estimates that increase significantly. This is because the size of the market is reduced to the demand response and storage technology. Technology like this, in general, can be used as a counterweight to a certain size of the market by looking at the quality of market participants. Lack of knowledge of technology and its groups is the main reason since competitive technology can be used for decision-making information for processes in a smoother energy transition.

The distribution of solution technology portfolios in each region for VRE integration contained in the literature seems to be very generic. Thus, the guidance given to companies and policymakers always fails to develop business policies and strategies. For future decision making, it can be assisted through an interrelation matrix such as preparing proposals and technology roadmaps both nationally and internationally. This aims to be able to decarbonize the energy sector. Interrelation material functions to match each category as well as some of the history of each country. Every quality challenge has occurred regionally for high distributed VRE penetration so that the spread of flexibility is needed especially distributed technology networks. Countries with a high penetration of VRE generators are southern England, southern and northern Italy and southern Germany [ 109 ]. Although the availability of data spread flexibility is not available for distributed technology networks in certain regions, projects such as the RD&D smart grid are technologies with very high priority for policymakers and companies in these countries [ 24 , 28 , 78 ]. The challenge of flow for the transmission rate reached by countries such as Germany, in general, requires a technology system with a centralized network. Such systems, such as transmission networks or amplifications, must be expanded, active power control and HVDC transmission systems. Germany is currently preparing several large projects that can be utilized by using technology. This is done after the assessment phase in determining the design and size of the complex installation has been completed.

Countries such as Ireland and Spain have done similar things, both of which have faced stability challenges. On the other hand, the transmission operator system is set as the centralized controller of the VRE generator. It aims to the needs of VRE generators to support network stability [ 3 , 102 , 108 ]. Besides, the investigation was carried out to ease the limitation of the stability criteria. Finally, solving the challenge of balance can only be done through technology flexibility. California, for example, is a country that have difficulty of being able to maintain power balance when the sun changes night so that the VRE generation has decreased significantly [ 32 ]. To encourage investment in storage with more flexible generators and environmentally friendly renewable energy, the State of California has introduced several new products [ 2 , 29 , 30 ]. Thus, interrelation matrix can be concluded that its function can be carried out by business people and those who make policies in identifying solutions technology groups. Finally, the challenges that are prevalent in certain areas can be reduced and the formulation of steps and policy strategies in supporting the dissemination of technology can be easily carried out.

Frequent debates between actors to prioritize technological solutions in VRE and irrigation management in the energy sector have often been carried out. Priority for technology solutions in integrating VRE with costs and ease of implementation is reported by several researchers ([ 21 , 35 , 99 , 100 ]. This perspective has short-term benefits, also, the potential solutions that are perpetuated from this perspective are differences in facing challenges. Technology solutions are prioritized based on their respective solutions so that technology flexibility can be used as a solution to the challenges of VRE. This is as stated by experts in supporting the potential of technological flexibility ([ 99 , 100 , 126 ]). The results of the analysis can support the call for decision-makers adjusted to market rules or the placement of newly applied policies. Remuneration schemes for reactive power are introduced in the regional market. However, technology ratings are determined solely based on their respective potential and do not take into account other technological solutions that contribute to solving challenges. Besides, the solution space is different among all challenges. To consider these factors, the ranking of technologies can be adjusted to their potential in solving challenges. The preference for the deployment of this flexibility technology is specifically found in distributed and centralized VRE. Protection strategies with appropriate equipment can solve specific challenges, and higher interests can be achieved by the following perspectives. Response to requests both small and large is part of the technology solution. In addition, there are large generators with lower priority because of the limitations of the potential for more unique solutions. Relevantly to distinguish VRE integration, there are two examples large, small demand response spreads and large flexible conventional generators. Cost savings from existing solutions can be realized in the short term. However, it is not enough to only deal with the scope of the existing challenges or potential. The aspects discussed can be assumed to confirm the benefits of the results of the analysis for policymakers as a whole.

The results of the analysis carried out have important limitations to be considered when interpreting the final results. A review of specific research on existing challenges can improve VRE penetration. However, additional challenges which are not listed in this study can also face challenges such as the electric power system. At the same time, analysis of challenges was also found in power systems with lower VRE penetration. Specifically, the analysis conducted in this study is a challenge that is directly related to technology solutions. This analysis does not measure one technology solution that can solve only certain challenges. In addition, the future developments beyond the scope of this analysis can be reduced, e.g. the emergence of new solution technologies that can change frequency stability criteria or more robust end-user equipment such as variable frequency drives. Furthermore, the specific costs of the solution technology, the urgency of the challenges or the feasibility of implementing the solution technology are not considered. This is due to environmental constraints such as high land, social areas such as the public for receiving the final transmission line. This quantification is adapted to specific contexts with differences in power system characteristics. Furthermore, high levels of uncertainty are more vulnerable when considered such as revenue and costs than differences in applications and technology solutions. This need is needed for the need to think in grouping portfolios or technologies that focus on the completion of integrated VRE.

4 Conclusion

Specifically, the review in this research is to study the integration of VRE systems that are connected with modern power systems and technology to overcome challenges. Besides, the need for power system technology in increasing VRE market share with complex integration is also discussed. The collection of challenges undertaken in this study was drawn from a variety of literature relating to technology solutions in integrating VRE. The challenges developed can consistently integrate VRE which is the root problem of this analysis. The results of this analysis are supplemented by data from interviews of experts who have helped in investigations related to technology solutions and their challenges.

The results of the analysis with some insights outlined in the study can be summarized as follows

VRE integrated with challenges can affect the characteristics of the power system.

Technology solutions that vary with the number of challenges can be significantly overcome. In general, technology flexibility has a higher solution potential than the use of grid technology.

The identified technological solution facilities are intended to be able to overcome challenges in several categories.

Identification of challenges from various practice literature can be arranged and collected based on the root of the problem to produce each of the more exclusive challenge categories.

Categories and collections of technology solutions are used to test challenges that can be overcome by a single technology.

The size of potential solutions becomes very important for companies or policymakers in promoting certain technologies and their respective solutions.

Some of the descriptions presented in this review are a starting point for future research related to this topic. The relationship between technology solutions and challenges is one of the new fields of research. This is done with an estimated cost compared to the use of different solution technologies and can be introduced comparatively to the environment as a whole. Life Cycle Assessment (LCA) can be used to measure costs integrated with VRE because the installed capacity with future projections is available [ 41 , 107 , 114 , 125 ]. This system can significantly improve recommendations on policies issued. Overall, the development of individual solutions technology that is integrated with VRE is an issue that has a high price for the transition in the energy sector in a sustainable manner. In this case, a further investigation between the characteristics of different power systems and geographies is on one side of the technology solutions and challenges with different sides.

5 Nomenclature

VRE Variable Renewable energy

HVDC High-Voltage Direct Current

RE Renewable Energy

LCA Life Cycle Assessment

RET Renewable Energy Technology

PV Photovoltaics

Abdelshafy, A. M., Jurasz, J., Hassan, H., & Mohamed, A. M. (2020). Optimized energy management strategy for grid connected double storage (pumped storage-battery) system powered by renewable energy resources. Energy , 192 , 116615. https://doi.org/10.1016/j.energy.2019.116615 .

Article   Google Scholar  

Abdul-Rahman, K. H., Alarian, H., Rothleder, M., Ristanovic, P., Vesovic, B., & Lu, B. (2012). Enhanced system reliability using flexible ramp constraint in CAISO market. In 2012 IEEE power and energy society general meeting , (pp. 1–6). https://doi.org/10.1109/PESGM.2012.6345371 .

Chapter   Google Scholar  

Ackermann, T., Martensen, N., Brown, T., Schierhorn, P. P., Boshell, F., Gafaro, F., & Ayuso, M. (2016). Scaling up variable renewable power: The role of grid codes World Future Energy.

Google Scholar  

Agency, I. E. (2005). Variability of wind power and other renewables: Management options and strategies International Energy Agency.

Agency, I. E. (2014). The power of transformation: Wind, sun and the economics of flexible power systems IEA.

Book   Google Scholar  

Alanazi, M., Mahoor, M., & Khodaei, A. (2020). Co-optimization generation and transmission planning for maximizing large-scale solar PV integration. International Journal of Electrical Power & Energy Systems , 118 , 105723. https://doi.org/10.1016/j.ijepes.2019.105723 .

Alet, P.-J., Baccaro, F., De Felice, M., Efthymiou, V., Mayr, C., Graditi, G., … Tselepis, S. (2015). Quantification, challenges and outlook of PV integration in the power system: A review by the European PV technology platform EU PVSEC 2015.

Al-Haddad, K. (2010). Power quality issues under constant penetration rate of renewable energy into the electric network. In Proceedings of 14th international power electronics and motion control conference EPE-PEMC 2010 , (pp. S11-39–S11-49). https://doi.org/10.1109/EPEPEMC.2010.5606699 .

Alizadeh, M. I., Parsa Moghaddam, M., Amjady, N., Siano, P., & Sheikh-El-Eslami, M. K. (2016). Flexibility in future power systems with high renewable penetration: A review. Renewable and Sustainable Energy Reviews , 57 , 1186–1193. https://doi.org/10.1016/j.rser.2015.12.200 .

Allard, S., Debusschere, V., Mima, S., Quoc, T. T., Hadjsaid, N., & Criqui, P. (2020). Considering distribution grids and local flexibilities in the prospective development of the European power system by 2050. Applied Energy , 270 , 114958. https://doi.org/10.1016/j.apenergy.2020.114958 .

Al-Shetwi, A. Q., Hannan, M. A., Jern, K. P., Mansur, M., & Mahlia, T. M. I. (2020). Grid-connected renewable energy sources: Review of the recent integration requirements and control methods. Journal of Cleaner Production , 253 , 119831. https://doi.org/10.1016/j.jclepro.2019.119831 .

Al-Shetwi, A. Q., Sujod, M. Z., Blaabjerg, F., & Yang, Y. (2019). Fault ride-through control of grid-connected photovoltaic power plants: A review. Solar Energy , 180 , 340–350. https://doi.org/10.1016/j.solener.2019.01.032 .

Analytics, C. (2020). Web of Science. Retrieved from https://login.webofknowledge.com/error/Error?Src=IP&Alias=WOK5&Error=IPError&Params=%26Error%3DClient.NullSessionID&PathInfo=%2F&RouterURL , https://%3A%2F%2Fwww.webofknowledge.com%2F&Domain=.webofknowledge.com

Andersen, B., & Fagerhaug, T. (2006). Root cause analysis: Simplified tools and techniques . Quality Press; Journal for Healthcare Quality.  https://journals.lww.com/jhqonline/Citation/2002/05000/Root_Cause_Analysis__Simplified_Tools_and.12.aspx .

Armghan, H., Yang, M., Wang, M. Q., Ali, N., & Armghan, A. (2020). Nonlinear integral backstepping based control of a DC microgrid with renewable generation and energy storage systems. International Journal of Electrical Power & Energy Systems , 117 , 105613. https://doi.org/10.1016/j.ijepes.2019.105613 .

Arthur, W. B. (2009). The nature of technology: What it is and how it evolves . Simon and Schuster. https://www.books.google.co.id/books?hl=en&lr=&id=3qHs-XYXN0EC&oi=fnd&pg=PA1&dq=The+nature+of+technology:+What+it+is+and+how+it+evolves&ots=5ZNboK7VAf&sig=KJ8N_DMgENEfOAU-wGRAlXUjMEw&redir_esc=y#v=onepage&q=The%20nature%20of%20technology%3A%20What%20andit%20is%20how%20andit%20is%2020evolves&f=false .

Bartolini, A., Carducci, F., Munoz, C. B., & Comodi, G. (2020). Energy storage and multi energy systems in renewable energy communities with high renewable energy penetration. Renewable Energy . https://doi.org/10.1016/j.renene.2020.05.131 .

Batalla-Bejerano, J., & Trujillo-Baute, E. (2016). Impacts of intermittent renewable generation on electricity system costs. Energy Policy , 94 , 411–420. https://doi.org/10.1016/j.enpol.2015.10.024 .

Battaglini, A., Lilliestam, J., Haas, A., & Patt, A. (2009). Development of SuperSmart grids for a more efficient utilisation of electricity from renewable sources. Journal of Cleaner Production , 17 (10), 911–918. https://doi.org/10.1016/j.jclepro.2009.02.006 .

Bazilian, M., Denny, E., & O’Malley, M. (2004). Challenges of increased wind energy penetration in Ireland. Wind Engineering , 28 (1), 43–55.

Bird, L., Milligan, M., & Lew, D. (2013). Integrating variable renewable energy: Challenges and solutions . Golden: National Renewable Energy lab.(NREL).

Blarke, M. B., & Jenkins, B. M. (2013). SuperGrid or SmartGrid: Competing strategies for large-scale integration of intermittent renewables? Energy Policy , 58 , 381–390. https://doi.org/10.1016/j.enpol.2013.03.039 .

Cailliau, M., Ogando, J. A., Egeland, H., Ferreira, R., Feuk, H., Figel, F., … Villar, C. M. (2010). Integrating intermittent renewable sources into the eu electricity system by 2020: Challenges and solutions . Brussels: Union of the Electricity Industry [EURELECTRIC].

Cambini, C., Meletiou, A., Bompard, E., & Masera, M. (2016). Market and regulatory factors influencing smart-grid investment in Europe: Evidence from pilot projects and implications for reform. Utilities Policy , 40 , 36–47. https://doi.org/10.1016/j.jup.2016.03.003 .

Chandler, H. (2011). Harnessing variable renewables: A guide to the balancing challenge . Paris: International Energy Agency.

Child, M., Kemfert, C., Bogdanov, D., & Breyer, C. (2019). Flexible electricity generation, grid exchange and storage for the transition to a 100% renewable energy system in Europe. Renewable Energy , 139 , 80–101. https://doi.org/10.1016/j.renene.2019.02.077 .

Cifor, A., Denholm, P., Ela, E., Hodge, B.-M., & Reed, A. (2015). The policy and institutional challenges of grid integration of renewable energy in the western United States. Utilities Policy , 33 , 34–41. https://doi.org/10.1016/j.jup.2014.11.001 .

Colak, I., Fulli, G., Sagiroglu, S., Yesilbudak, M., & Covrig, C.-F. (2015). Smart grid projects in Europe: Current status, maturity and future scenarios. Applied Energy , 152 , 58–70. https://doi.org/10.1016/j.apenergy.2015.04.098 .

Cornelius, A., Bandyopadhyay, R., & Patiño-Echeverri, D. (2018). Assessing environmental, economic, and reliability impacts of flexible ramp products in MISO’s electricity market. Renewable and Sustainable Energy Reviews , 81 , 2291–2298. https://doi.org/10.1016/j.rser.2017.06.037 .

Cui, M., & Zhang, J. (2018). Estimating ramping requirements with solar-friendly flexible ramping product in multi-timescale power system operations. Applied Energy , 225 , 27–41. https://doi.org/10.1016/j.apenergy.2018.05.031 .

Das, P., Mathuria, P., Bhakar, R., Mathur, J., Kanudia, A., & Singh, A. (2020). Flexibility requirement for large-scale renewable energy integration in Indian power system: Technology, policy and modeling options. Energy Strategy Reviews , 29 , 100482. https://doi.org/10.1016/j.esr.2020.100482 .

Denholm, P., O’Connell, M., Brinkman, G., & Jorgenson, J. (2015). Overgeneration from solar energy in California. A field guide to the duck chart . Golden: National Renewable Energy lab.(NREL).

Díaz, G., Coto, J., & Gómez-Aleixandre, J. (2019). Optimal operation value of combined wind power and energy storage in multi-stage electricity markets. Applied Energy , 235 , 1153–1168. https://doi.org/10.1016/j.apenergy.2018.11.035 .

Dileep, G. (2020). A survey on smart grid technologies and applications. Renewable Energy , 146 , 2589–2625. https://doi.org/10.1016/j.renene.2019.08.092 .

DNV, G. L (2014). Integration of renewable energy in Europe, Bonn .

Douglas-Smith, D., Iwanaga, T., Croke, B. F. W., & Jakeman, A. J. (2020). Certain trends in uncertainty and sensitivity analysis: An overview of software tools and techniques. Environmental Modelling and Software , 124 , 104588. https://doi.org/10.1016/j.envsoft.2019.104588 .

EIA (2020). Installed electricity capacity Retrieved from https://www.eia.gov/international/data/world .

Elsevier (2020). ScienceDirect Retrieved from https://www.sciencedirect.com/ .

Erdiwansyah, M., Mamat, R., Sani, M. S. M., Khoerunnisa, F., & Kadarohman, A. (2019). Target and demand for renewable energy across 10 ASEAN countries by 2040. The Electricity Journal , 32 (10), 106670. https://doi.org/10.1016/J.TEJ.2019.106670 .

Erdiwansyah, Mamat, R., Sani, M. S. M., & Sudhakar, K. (2019). Renewable energy in Southeast Asia: Policies and recommendations. Science Total Environment . https://doi.org/10.1016/j.scitotenv.2019.03.273 .

Finnveden, G., Hauschild, M. Z., Ekvall, T., Guinée, J., Heijungs, R., Hellweg, S., … Suh, S. (2009). Recent developments in life cycle assessment. Journal of Environmental Management , 91 (1), 1–21. https://doi.org/10.1016/j.jenvman.2009.06.018 .

Forbes, K. F., & Zampelli, E. M. (2019). Wind energy, the price of carbon allowances, and CO2 emissions: Evidence from Ireland. Energy Policy , 133 , 110871. https://doi.org/10.1016/j.enpol.2019.07.007 .

Gan, L., Jiang, P., Lev, B., & Zhou, X. (2020). Balancing of supply and demand of renewable energy power system: A review and bibliometric analysis. Sustainable Futures , 2 , 100013. https://doi.org/10.1016/j.sftr.2020.100013 .

Ghenai, C., & Bettayeb, M. (2019). Grid-tied solar PV/fuel cell hybrid power system for university building. Energy Procedia , 159 , 96–103. https://doi.org/10.1016/j.egypro.2018.12.025 .

González, A., Daly, G., & Gleeson, J. (2016). Congested spaces, contested scales – A review of spatial planning for wind energy in Ireland. Landscape and Urban Planning , 145 , 12–20. https://doi.org/10.1016/j.landurbplan.2015.10.002 .

Hadjilambrinos, C. (2000). Understanding technology choice in electricity industries: A comparative study of France and Denmark. Energy Policy , 28 (15), 1111–1126. https://doi.org/10.1016/S0301-4215(00)00067-7 .

Hannan, M. A., Tan, S. Y., Al-Shetwi, A. Q., Jern, K. P., & Begum, R. A. (2020). Optimized controller for renewable energy sources integration into microgrid: Functions, constraints and suggestions. Journal of Cleaner Production , 256 , 120419. https://doi.org/10.1016/j.jclepro.2020.120419 .

Hare, J., Shi, X., Gupta, S., & Bazzi, A. (2016). Fault diagnostics in smart micro-grids: A survey. Renewable and Sustainable Energy Reviews , 60 , 1114–1124. https://doi.org/10.1016/j.rser.2016.01.122 .

Hedegaard, K., & Meibom, P. (2012). Wind power impacts and electricity storage – A time scale perspective. Renewable Energy , 37 (1), 318–324. https://doi.org/10.1016/j.renene.2011.06.034 .

Hirth, L., & Müller, S. (2016). System-friendly wind power: How advanced wind turbine design can increase the economic value of electricity generated through wind power. Energy Economics , 56 , 51–63. https://doi.org/10.1016/j.eneco.2016.02.016 .

Hirth, L., & Ziegenhagen, I. (2015). Balancing power and variable renewables: Three links. Renewable and Sustainable Energy Reviews , 50 , 1035–1051. https://doi.org/10.1016/j.rser.2015.04.180 .

Hlalele, T. S., Sun, Y., & Wang, Z. (2019). Faults classification and identification on smart grid: Part-a status review. Procedia Manufacturing , 35 , 601–606. https://doi.org/10.1016/j.promfg.2019.05.085 .

Holttinen, H. (2012). Wind integration: Experience, issues, and challenges. Wiley Interdisciplinary Reviews: Energy and Environment , 1 (3), 243–255.

Houseman, D. (2009). True integration challenges for distributed resources in the distribution grid. In CIRED 2009-20th international conference and exhibition on electricity distribution-part 1 , (pp. 1–4). IET.  https://ieeexplore.ieee.org/abstract/document/5255832 .

Ilisiu, D., Munteanu, C., & Topa, V. (2009). Renewable integration in Romanian power system, challenge for Transelectrica company. In 2009 international conference on clean electrical power , (pp. 710–714). IEEE.  https://ieeexplore.ieee.org/abstract/document/5211974 .

IPCC (2001). Climate change 2001: The scientific basis. Contribution of working group I to the third assessment report of the Interngovernmental panel on climate change .

Islam, M. R., Lu, H., Hossain, M. J., & Li, L. (2019). Mitigating unbalance using distributed network reconfiguration techniques in distributed power generation grids with services for electric vehicles: A review. Journal of Cleaner Production , 239 , 117932. https://doi.org/10.1016/j.jclepro.2019.117932 .

Jayaweera, D. (2016). Smart power systems and renewable energy system integration . Springer.  https://link.springer.com/book/10.1007%2F978-3-319-30427-4 .

Javed, M. S., Ma, T., Jurasz, J., & Amin, M. Y. (2020). Solar and wind power generation systems with pumped hydro storage: Review and future perspectives. Renewable Energy , 148 , 176–192. https://doi.org/10.1016/j.renene.2019.11.157 .

Jonaitis, A., Gudzius, S., Morkvenas, A., Azubalis, M., Konstantinaviciute, I., Baranauskas, A., & Ticka, V. (2018). Challenges of integrating wind power plants into the electric power system: Lithuanian case. Renewable and Sustainable Energy Reviews , 94 , 468–475. https://doi.org/10.1016/j.rser.2018.06.032 .

Karbouj, H., Rather, Z. H., Flynn, D., & Qazi, H. W. (2019). Non-synchronous fast frequency reserves in renewable energy integrated power systems: A critical review. International Journal of Electrical Power & Energy Systems , 106 , 488–501. https://doi.org/10.1016/j.ijepes.2018.09.046 .

Karimi, M., Mokhlis, H., Naidu, K., Uddin, S., & Bakar, A. H. A. (2016). Photovoltaic penetration issues and impacts in distribution network – A review. Renewable and Sustainable Energy Reviews , 53 , 594–605. https://doi.org/10.1016/j.rser.2015.08.042 .

Kassakian, J. G., Schmalensee, R., Desgroseilliers, G., Heidel, T. D., Afridi, K., Farid, A., … Kirtley, J. (2011). The future of the electric grid , (pp. 197–234). Massachusetts Institute of Technology, Tech Rep.  http://energy.mit.edu/research/future-electric-grid/ .

Katiraei, F., & Agüero, J. R. (2011). Solar PV integration challenges. IEEE Power and Energy Magazine , 9 (3), 62–71. https://doi.org/10.1109/MPE.2011.940579 .

Kayalvizhi, S., & Vinod Kumar, D. M. (2018). Optimal planning of active distribution networks with hybrid distributed energy resources using grid-based multi-objective harmony search algorithm. Applied Soft Computing , 67 , 387–398. https://doi.org/10.1016/j.asoc.2018.03.009 .

Kharrazi, A., Sreeram, V., & Mishra, Y. (2020). Assessment techniques of the impact of grid-tied rooftop photovoltaic generation on the power quality of low voltage distribution network - a review. Renewable and Sustainable Energy Reviews , 120 , 109643. https://doi.org/10.1016/j.rser.2019.109643 .

Krauter, S. (2018). Simple and effective methods to match photovoltaic power generation to the grid load profile for a PV based energy system. Solar Energy, 159, 768–776. do: https://doi.org/10.1016/j.solener.2017.11.039

Krauter, S., & Japs, E. (2014). Integration of PV into the energy system: Challenges and measures for generation and load management. In 2014 IEEE 40th photovoltaic specialist conference (PVSC) , (pp. 3123–3128). IEEE.

Kumar, A., & Pan, S.-Y. (2020). Opportunities and challenges for renewable energy integrated water-energy nexus technologies. Water-Energy Nexus . https://doi.org/10.1016/j.wen.2020.03.006 .

Lahaçani, N. A., Aouzellag, D., & Mendil, B. (2010). Contribution to the improvement of voltage profile in electrical network with wind generator using SVC device. Renewable Energy , 35 (1), 243–248. https://doi.org/10.1016/j.renene.2009.04.020 .

Li, Y., Liu, H., Fan, X., & Tian, X. (2020). Engineering practices for the integration of large-scale renewable energy VSC-HVDC systems. Global Energy Interconnection , 3 (2), 149–157. https://doi.org/10.1016/j.gloei.2020.05.007 .

Liang, X. (2017). Emerging power quality challenges due to integration of renewable energy sources. IEEE Transactions on Industry Applications , 53 (2), 855–866. https://doi.org/10.1109/TIA.2016.2626253 .

Liebensteiner, M., & Wrienz, M. (2020). Do intermittent renewables threaten the electricity supply security? Energy Economics , 87 , 104499. https://doi.org/10.1016/j.eneco.2019.104499 .

Lund, P. D., Lindgren, J., Mikkola, J., & Salpakari, J. (2015). Review of energy system flexibility measures to enable high levels of variable renewable electricity. Renewable and Sustainable Energy Reviews , 45 , 785–807. https://doi.org/10.1016/j.rser.2015.01.057 .

Luo, K., Shi, W., & Wang, W. (2020). Extreme scenario extraction of a grid with large scale wind power integration by combined entropy-weighted clustering method. Global Energy Interconnection , 3 (2), 140–148. https://doi.org/10.1016/j.gloei.2020.05.006 .

Lyons, G. (2002). Internet: Investigating new technology’s evolving role, nature and effects on transport. Transport Policy , 9 (4), 335–346. https://doi.org/10.1016/S0967-070X(02)00023-9 .

Maddaloni, J. D., Rowe, A. M., & van Kooten, G. C. (2009). Wind integration into various generation mixtures. Renewable Energy , 34 (3), 807–814. https://doi.org/10.1016/j.renene.2008.04.019 .

Malik, A. S., Albadi, M., Al-Jabri, M., Bani-Araba, A., Al-Ameri, A., & Al Shehhi, A. (2018). Smart grid scenarios and their impact on strategic plan—A case study of Omani power sector. Sustainable Cities and Society , 37 , 213–221. https://doi.org/10.1016/j.scs.2017.11.015 .

Marinescu, C., & Serban, I. (2013). About the main frequency control issues in microgrids with renewable energy sources. In 2013 international conference on clean electrical power (ICCEP) , (pp. 145–150). https://doi.org/10.1109/ICCEP.2013.6586981 .

Marques, A. C., Fuinhas, J. A., & Pereira, D. S. (2019). The dynamics of the short and long-run effects of public policies supporting renewable energy: A comparative study of installed capacity and electricity generation. Economic Analysis and Policy , 63 , 188–206. https://doi.org/10.1016/j.eap.2019.06.004 .

McPherson, M., Harvey, L. D. D., & Karney, B. (2017). System design and operation for integrating variable renewable energy resources through a comprehensive characterization framework. Renewable Energy , 113 , 1019–1032. https://doi.org/10.1016/j.renene.2017.06.071 .

McPherson, M., & Stoll, B. (2020). Demand response for variable renewable energy integration: A proposed approach and its impacts. Energy , 197 , 117205. https://doi.org/10.1016/j.energy.2020.117205 .

Mohamed, A. A. S., El-Sayed, A., Metwally, H., & Selem, S. I. (2020). Grid integration of a PV system supporting an EV charging station using Salp swarm optimization. Solar Energy , 205 , 170–182. https://doi.org/10.1016/j.solener.2020.05.013 .

Moreno-Leiva, S., Haas, J., Junne, T., Valencia, F., Godin, H., Kracht, W., … Eltrop, L. (2020). Renewable energy in copper production: A review on systems design and methodological approaches. Journal of Cleaner Production , 246 , 118978. https://doi.org/10.1016/j.jclepro.2019.118978 .

MSB, I. E. C (2012). Grid integration of large-capacity renewable energy sources and use of large-capacity electrical energy storage, white paper .

Muzhikyan, A., Muhanji, S. O., Moynihan, G. D., Thompson, D. J., Berzolla, Z. M., & Farid, A. M. (2019). The 2017 ISO New England system operational analysis and renewable energy integration study (SOARES). Energy Reports , 5 , 747–792. https://doi.org/10.1016/j.egyr.2019.06.005 .

Nadjaran Toosi, A., Qu, C., de Assunção, M. D., & Buyya, R. (2017). Renewable-aware geographical load balancing of web applications for sustainable data centers. Journal of Network and Computer Applications , 83 , 155–168. https://doi.org/10.1016/j.jnca.2017.01.036 .

Navon, A., Kulbekov, P., Dolev, S., Yehuda, G., & Levron, Y. (2020). Integration of distributed renewable energy sources in Israel: Transmission congestion challenges and policy recommendations. Energy Policy , 140 , 111412. https://doi.org/10.1016/j.enpol.2020.111412 .

Nwaigwe, K. N., Mutabilwa, P., & Dintwa, E. (2019). An overview of solar power (PV systems) integration into electricity grids. Materials Science for Energy Technologies , 2 (3), 629–633. https://doi.org/10.1016/j.mset.2019.07.002 .

Odeh, R. P., & Watts, D. (2019). Impacts of wind and solar spatial diversification on its market value: A case study of the Chilean electricity market. Renewable and Sustainable Energy Reviews , 111 , 442–461. https://doi.org/10.1016/j.rser.2019.01.015 .

O’Flaherty, M., Riordan, N., O’Neill, N., & Ahern, C. (2014). A quantitative analysis of the impact of wind energy penetration on electricity prices in Ireland. Energy Procedia , 58 , 103–110. https://doi.org/10.1016/j.egypro.2014.10.415 .

Ouai, A., Mokrani, L., Machmoum, M., & Houari, A. (2018). Control and energy management of a large scale grid-connected PV system for power quality improvement. Solar Energy , 171 , 893–906. https://doi.org/10.1016/j.solener.2018.06.106 .

Pansera, M. (2010). The nature of technology: What it is and how it evolves, William Brian Arthur, free press, Nueva York (2009), 237 pp. Investigaciones de Historia Económica , 6 (18), 200–202. https://doi.org/10.1016/S1698-6989(10)70080-1 .

Passey, R., Spooner, T., MacGill, I., Watt, M., & Syngellakis, K. (2011). The potential impacts of grid-connected distributed generation and how to address them: A review of technical and non-technical factors. Energy Policy , 39 (10), 6280–6290. https://doi.org/10.1016/j.enpol.2011.07.027 .

Pearre, N., & Swan, L. (2020). Combining wind, solar, and in-stream tidal electricity generation with energy storage using a load-perturbation control strategy. Energy , 203 , 117898. https://doi.org/10.1016/j.energy.2020.117898 .

Peterson, C. R., & Ros, A. J. (2018). The future of the electric grid and its regulation: Some considerations. The Electricity Journal , 31 (2), 18–25. https://doi.org/10.1016/j.tej.2018.02.001 .

Pierre, I., Bauer, F., Blasko, R., Dahlback, N., Dumpelmann, M., Kainurinne, K., … Romano, D. (2011). Flexible generation: Backing up renewables, Brussels .

Qiu, Y., Li, Q., Pan, Y., Yang, H., & Chen, W. (2019). A scenario generation method based on the mixture vine copula and its application in the power system with wind/hydrogen production. International Journal of Hydrogen Energy , 44 (11), 5162–5170. https://doi.org/10.1016/j.ijhydene.2018.09.179 .

Rehtanz, C., Greve, M., Häger, U., Hilbrich, D., Kippelt, S., Kubis, A., … Schwippe, J. (2014a,b). Dena ancillary services study 2030. In Security and reliability of a power supply with a high percentage of renewable energy .

Reichenberg, L., Hedenus, F., Odenberger, M., & Johnsson, F. (2018). Tailoring large-scale electricity production from variable renewable energy sources to accommodate baseload generation in europe. Renewable Energy , 129 , 334–346. https://doi.org/10.1016/j.renene.2018.05.014 .

Robles, E., Haro-Larrode, M., Santos-Mugica, M., Etxegarai, A., & Tedeschi, E. (2019). Comparative analysis of European grid codes relevant to offshore renewable energy installations. Renewable and Sustainable Energy Reviews , 102 , 171–185. https://doi.org/10.1016/j.rser.2018.12.002 .

Rothleder, M., & Loutan, C. (2017). Chapter 6 - case study–renewable integration: Flexibility requirement, potential Overgeneration, and frequency response challenges. In E. Jones (Ed.), L. e. B. t.-r. E. I , (2nd ed., pp. 69–81). Boston: Academic. https://doi.org/10.1016/B978-0-12-809592-8.00006-8 .

Ruiz-Romero, S., Colmenar-Santos, A., Mur-Pérez, F., & López-Rey, Á. (2014). Integration of distributed generation in the power distribution network: The need for smart grid control systems, communication and equipment for a smart city — Use cases. Renewable and Sustainable Energy Reviews , 38 , 223–234. https://doi.org/10.1016/j.rser.2014.05.082 .

Sajadi, A., Strezoski, L., Strezoski, V., Prica, M., & Loparo, K. A. (2019). Integration of renewable energy systems and challenges for dynamics, control, and automation of electrical power systems. Wiley Interdisciplinary Reviews: Energy and Environment , 8 (1), e321.

Sanchez-Hidalgo, M.-A., & Cano, M.-D. (2018). A survey on visual data representation for smart grids control and monitoring. Sustainable Energy, Grids and Networks , 16 , 351–369. https://doi.org/10.1016/j.segan.2018.09.007 .

Santos, R., Aguiar Costa, A., Silvestre, J. D., & Pyl, L. (2020). Development of a BIM-based environmental and economic life cycle assessment tool. Journal of Cleaner Production , 265 , 121705. https://doi.org/10.1016/j.jclepro.2020.121705 .

Sato, H., & Yan, X. L. (2019). Study of an HTGR and renewable energy hybrid system for grid stability. Nuclear Engineering and Design , 343 , 178–186. https://doi.org/10.1016/j.nucengdes.2019.01.010 .

Sawin, J. L. (2012). Renewables 2012-global status report . Paris: Renewable Energy Policy Network for the 21st Century.

Schill, W.-P., & Zerrahn, A. (2020). Flexible electricity use for heating in markets with renewable energy. Applied Energy , 266 , 114571. https://doi.org/10.1016/j.apenergy.2020.114571 .

Shayestegan, M., Shakeri, M., Abunima, H., Reza, S. M. S., Akhtaruzzaman, M., Bais, B., … Amin, N. (2018). An overview on prospects of new generation single-phase transformerless inverters for grid-connected photovoltaic (PV) systems. Renewable and Sustainable Energy Reviews , 82 , 515–530. https://doi.org/10.1016/j.rser.2017.09.055 .

Silva, N., Cunha, J. C., & Vieira, M. (2017). A field study on root cause analysis of defects in space software. Reliability Engineering & System Safety , 158 , 213–229. https://doi.org/10.1016/j.ress.2016.08.016 .

Sinsel, S. R., Riemke, R. L., & Hoffmann, V. H. (2020). Challenges and solution technologies for the integration of variable renewable energy sources—A review. Renewable Energy , 145 , 2271–2285. https://doi.org/10.1016/j.renene.2019.06.147 .

Soust-Verdaguer, B., Llatas, C., & García-Martínez, A. (2016). Simplification in life cycle assessment of single-family houses: A review of recent developments. Building and Environment , 103 , 215–227. https://doi.org/10.1016/j.buildenv.2016.04.014 .

Sovacool, B. K. (2009). The intermittency of wind, solar, and renewable electricity generators: Technical barrier or rhetorical excuse? Utilities Policy , 17 (3), 288–296. https://doi.org/10.1016/j.jup.2008.07.001 .

Spodniak, P., & Bertsch, V. (2020). Is flexible and dispatchable generation capacity rewarded in electricity futures markets? A multinational impact analysis. Energy , 196 , 117050. https://doi.org/10.1016/j.energy.2020.117050 .

Springer (2020). Publish and review Retrieved from https://www.springer.com/gp .

Stappel, M., Gerlach, A.-K., Scholz, A., & Pape, C. (2015). The European power system in 2030: Flexibility challenges and integration benefits. In An analysis with a focus on the pentalateral energy forum region agora Energiewende/Fraunhofer IWES Avaialble at http://www.agora-energiewende de Accessed Sept.

Suman, S. (2018). Hybrid nuclear-renewable energy systems: A review. Journal of Cleaner Production , 181 , 166–177. https://doi.org/10.1016/j.jclepro.2018.01.262 .

Taliotis, C., Taibi, E., Howells, M., Rogner, H., Bazilian, M., & Welsch, M. (2017). Renewable energy technology integration for the island of Cyprus: A cost-optimization approach. Energy , 137 , 31–41. https://doi.org/10.1016/j.energy.2017.07.015 .

Tareen, W. U., Mekhilef, S., Seyedmahmoudian, M., & Horan, B. (2017). Active power filter (APF) for mitigation of power quality issues in grid integration of wind and photovoltaic energy conversion system. Renewable and Sustainable Energy Reviews , 70 , 635–655. https://doi.org/10.1016/j.rser.2016.11.091 .

Telukunta, V., Pradhan, J., Agrawal, A., Singh, M., & Srivani, S. G. (2017). Protection challenges under bulk penetration of renewable energy resources in power systems: A review. CSEE Journal of Power and Energy Systems , 3 (4), 365–379.

Thellufsen, J. Z., Lund, H., Sorknæs, P., Østergaard, P. A., Chang, M., Drysdale, D., … Sperling, K. (2020). Smart energy cities in a 100% renewable energy context. Renewable and Sustainable Energy Reviews , 129 , 109922. https://doi.org/10.1016/j.rser.2020.109922 .

Twaha, S., & Ramli, M. A. M. (2018). A review of optimization approaches for hybrid distributed energy generation systems: Off-grid and grid-connected systems. Sustainable Cities and Society , 41 , 320–331. https://doi.org/10.1016/j.scs.2018.05.027 .

Ueckerdt, F., Hirth, L., Luderer, G., & Edenhofer, O. (2013). System LCOE: What are the costs of variable renewables? Energy , 63 , 61–75. https://doi.org/10.1016/j.energy.2013.10.072 .

Van Hulle, F., Holttinen, H., Kiviluoma, J., Faiella, M., Kreutzkamp, P., Cutululis, N., … Ernst, B. (2014). Grid support services by wind and solar PV: A review of system needs, technology options, economic benefits and suitable market mechanisms: Synthesis report of the REserviceS project .

Velasquez, M. A., Barreiro-Gomez, J., Quijano, N., Cadena, A. I., & Shahidehpour, M. (2019). Distributed model predictive control for economic dispatch of power systems with high penetration of renewable energy resources. International Journal of Electrical Power & Energy Systems , 113 , 607–617. https://doi.org/10.1016/j.ijepes.2019.05.044 .

von Meier, A. (2011). Integration of renewable generation in California: Coordination challenges in time and space. In 11th international conference on electrical power quality and utilisation , (pp. 1–6). https://doi.org/10.1109/EPQU.2011.6128888 .

von Meier, A. (2014). Challenges to the integration of renewable resources at high system penetration . Berkeley: California Institute for Energy and Environments.  https://escholarship.org/uc/item/81x1c1t5 .

Wang, Y., Das, R., Putrus, G., & Kotter, R. (2020). Economic evaluation of photovoltaic and energy storage technologies for future domestic energy systems – A case study of the UK. Energy , 203 , 117826. https://doi.org/10.1016/j.energy.2020.117826 .

Wong, J., Lim, Y. S., Tang, J. H., & Morris, E. (2014). Grid-connected photovoltaic system in Malaysia: A review on voltage issues. Renewable and Sustainable Energy Reviews , 29 , 535–545. https://doi.org/10.1016/j.rser.2013.08.087 .

Worighi, I., Maach, A., Hafid, A., Hegazy, O., & Van Mierlo, J. (2019). Integrating renewable energy in smart grid system: Architecture, virtualization and analysis. Sustainable Energy, Grids and Networks , 18 , 100226. https://doi.org/10.1016/j.segan.2019.100226 .

Download references

Acknowledgements

This research supported by PNBP Universitas Syiah Kuala, Research Institutions and Community Service.

About the authors

Erdiwansyah: Born in Desa Meunafa Kec. Salang, Kab. Simeulue Aceh Province at 14 March 1984. Erdiwansyah is a lecturer at the Faculty of Engineering, University Serambi Mekkah, and Banda Aceh, Indonesia since 2014 until now. In 2020 this was registered as a PhD of Engineering Student at Universitas Syiah Kuala. The Master’s degree was pursued at the Department of Electrical Engineering at Universitas Syiah Kuala, Banda Aceh, Indonesia, completed in 2016. Furthermore, the bachelor’s degree was obtained in August 2012 from the Faculty of Engineering Department, Universitas Serambi Mekkah Banda Aceh. Currently, besides studying, he also helps research professors at Universitas Syiah Kuala, Banda Aceh.

Mahidin: Born in T. Gajah Kec. Tnh. Jambo Aye at 3 April 1970, the eldest one out of 6 siblings. Finished the elementary school in SDN Lhokbeuringen T. Gajah at 1982, Junior High School at SMPN 1 and Senior High School at SMAN 1 Panton Labu, Kec. Tnh. Jambo Aye, North Aceh, in 1985 and 1988, respectively. Moreover, undergraduate degree was earn at August 1994 from Department of Chemical Engineering, Syiah Kuala University. Magister degree was pursued at Department of Chemical Engineering, ITB in October 1999, and received Doctor of Engineering in Resource and Energy Science from Graduate School of Science and Technology, Kobe University in September 2003. He was awarded a professor in chemical engineering in 2018. Fields of research are treatment and utilization of energy resources, especially renewable energy resources and mix of energy (energy diversification).

Husni Husin Ph. D, is a Professor of Chemical Reaction Engineering at Syiah Kuala University. She joined Chemical Engineering Department since December 1994; Born: 1965, Samalanga, Aceh, Indonesia; Education: Syiah Kuala University (1990); Institute Technology Bandung (2000); National Taiwan University Science and Technology (NTUST) Taiwan (2011); The title of her dissertation is “Fabrication of La-doped NaTaO3 via H2O2 Assisted Sol-gel Route and Their Photocatalytic Activity for Hydrogen Production”; Her research interests are: Nanomaterial for Clean Energy production (Photocatalytic, Solar cell, Biodiesel, Biofuel, Fuel Cell), Heterogeneous Catalyst and Application, Adsorbent and Application;

Nasaruddin received the B.Eng. degree in Electrical Engineering from Sepuluh Nopember Institute of Technology, Surabaya, Indonesia in 1997. Then he received M. Eng and D. Eng in Physical Electronics and Informatics, Graduate School of Engineering, Osaka City University, Japan, in 2006 and 2009, respectively. He is a lecturer at Electrical Engineering Department, Syiah Kuala University. He was head of master of Electrical Engineering Programme; graduate school of Syiah Kuala University. Currently, he is head of Electrical and Computer Engineering Department, Faculty of Engineering, Syiah Kuala University. He has published several papers in international journals and accredited national journals. His research interests include digital communications, information theory, optical communications and ICT applications for disaster. He is a member of IEEE and IAES.

Dr. Ir. Muhammad Zaki, M. Sc is a lecturer and researcher in Chemical Engineering Department, Faculty of Engineering, Unsyiah since 1992. Received a Bachelor degree (Ir) in Chemical Engineering Department of Unsyiah, then continued S2 (M.Sc) and S3 (Dr.) at Universiti Kebangsaan Malaysia in Chemical and Process Engineering Department.

Muhibbuddin I completed my Ph. D in Technical and Vocational in Mechanical Engineering from The State University of Padang, Indonesia, in 2016 under the supervision of Prof. Dr. Nizwardi Jalinus and finished Master of Engineering degree in Mechanical Engineering Joint Programme between Gadjah Mada University and Bandung Technology Institute, in 2012. Since 2007 worked as Traineer Machining at Sandvik Light Industrial Park PT. Freeport Indonesia Tembagapura Papua Indonesia and resigned in 2008 for graduating as civil servant. Since college, I have been interested in Energy Conversion Machines especially water turbines, windmills and applied engineering. Besides studying, I am also active in Laboratory and Micro Hydro Power Plants Development Centers and research final project Bachelor; “Design and Manufacture of Transmission System a Portable Propeller Water Turbine 4 kW Capacity for Micro Hydro Power Plants”. The Master of Engineering focuses on the research; “Study of Utilization of Bamboo Parts as Blades of Pelton Water Turbine for Enhancing Rural Energy Technology to Support the Energy Independent Village Program”. Doctoral Research; “The development of Cooperative Project-Based Learning (CPBL) models for Energy Conversion Machines in Technical Vocational Education and Training in Mechanical Engineering”. I served as Head of Devision Human Resources Teacher and Education Personnel (Echelon III) Southwest Aceh Regency Education and Culture Office from 2018 to 2019. Since October 1, 2019 until now I am joined as a lecturer in Mechanical and Industrial Engineering, Faculty of Engineering, Syiah Kuala University, Banda Aceh.

The funding of this research is the grand research of the professor with the contract number of (32/UN11.2.1/PT.01.03/PNBP/2020).

Author information

Authors and affiliations.

Doctoral Program, School of Engineering, Universitas Syiah Kuala, Banda Aceh, 23111, Indonesia

Erdiwansyah

Faculty of Engineering, Universitas Serambi Mekkah, Banda Aceh, 23245, Indonesia

Department of Chemical Engineering, Universitas Syiah Kuala, Banda Aceh, 23111, Indonesia

Mahidin, H. Husin & M. Zaki

Department of Electrical and Computer Engineering, Universitas Syiah Kuala, Banda Aceh, 23111, Indonesia

Department of Mechanical and Industrial Engineering, Universitas Syiah Kuala, Banda Aceh, 23111, Indonesia

Muhibbuddin

You can also search for this author in PubMed   Google Scholar

Contributions

1. Erdiwansyah: The first author acts as the author of all article content and data collection such as literature searches and other data that support this research. 2. Mahidin: The second author acts as the draft writer of the article and also as a review for the refinement of the article before it is sent to this journal. 3. H. Husin: The third author acts as a controller of the writing done by the first author. In addition, the third author is also tasked with analyzing the literature data collected and written by the first author. 4. Nasaruddin: The fourth author acts as a drafter and design of articles written by the first author. In addition, the fourth author is also a policy maker for this article and serves as the final review and editing of this journal. 5. M. Zaki: The fourth author acts as a contributor to research funding in addition to funding from the grand research. The fourth author also acts as analysis and refinement of the final article. 6. Muhibbuddin: This sixth author acts as a fund contributor for checking language and words and sentences for English language experts. The sixth author has also helped to revise the end of the journal jointly with all the authors in this article. The author(s) read and approved the final manuscript.

Corresponding authors

Correspondence to Erdiwansyah or Mahidin .

Ethics declarations

Competing interests.

There are no conflicts to declare.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ .

Reprints and permissions

About this article

Cite this article.

Erdiwansyah, Mahidin, Husin, H. et al. A critical review of the integration of renewable energy sources with various technologies. Prot Control Mod Power Syst 6 , 3 (2021). https://doi.org/10.1186/s41601-021-00181-3

Download citation

Received : 13 July 2020

Accepted : 12 January 2021

Published : 23 February 2021

DOI : https://doi.org/10.1186/s41601-021-00181-3

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Integration RE
• Energy source
• Technology system energy
• Power system
• Variable RE

• Reference Manager
• Simple TEXT file

People also looked at

Mini review article, a critical survey on renewable energy applications in the philippines and china: present challenges and perspectives.

• Law School, Kunming University of Science and Technology, Kunming, China

China’s Belt and Road (B&R) initiative provides new ideas and opportunities for international cooperation. Renewable energy plays a crucial role not only in the national sustainable development framework of China and the Philippines but also in bilateral cooperation between them. However, some obstacles still need to be addressed because renewable energy cooperation between China and the Philippines has not been thoroughly and comprehensively studied to date. Based on an in-depth analysis of current renewable energy cooperation between China and the Philippines, this paper employs PESTEL analysis to fully investigate the cooperative advantages and disadvantages by considering politics (P), economy (E), society (S), technology (T), environment (E), and legislation (L) and proposes several constructive suggestions. The ultimate purpose was to design feasible schemes to ensure the sufficient utilization of renewable energy and the construction of integrated power grid systems to meet shortages of electricity supply especially in the isolated small islands in the Philippines through cooperation with China. In particular, it offers valuable advice concerning the U.S.-China trade war and COVID- 19 pandemic, outlining how cooperation in the exploitation of potential renewable energy is vital.

Introduction

In response to the advantages of renewable energy ( Gullberg et al., 2014 ), many countries and regional organizations have entered into cooperative targeted renewable energy initiatives ( Anand et al., 2021 ; Mohan, 2021 ; Sasmita and Sidhartha, 2021 ). Existing research on renewable cooperation ( Feng et al., 2020 ) is mainly focused on a comprehensive analysis of the renewable energy cooperative mechanism between two countries ( Suryanarayana and Saumendra, 2020 ), a country and regional organizations ( Mehdi and Mehdi, 2020 ), and regional organizations ( Indeo, 2019 ), by forecasting the potentiality of cooperation and undertaking analysis via a mathematical model ( Satish and Vinod, 2020 ). However, three existing gaps need to be overcome.

• Most previous studies fail to comprehensively analyze the advantages and disadvantages of renewable energy cooperation between specific countries under B & R.

• Specific suggestions based on the effective factors of cooperation such as politics, economy, society, technology, environment, and legislation have not been proposed.

• The latest factors, including the COVID-19 pandemic and the United States-China trade war, have not been addressed.

This paper focuses on the exploitation of renewable energy cooperation between China and the Philippines, proposing a new perspective in response to this new context and undertakes a comprehensive investigation of a cooperative scheme between two countries. Based on a systematic overview of renewable energy systems in China and the Philippines, including the current situation, existing problems, policies, and plans, the basis and challenges for further cooperation between the two countries are explored ( Renewable Energy Development in the Philippines and Renewable Energy Development Status in China Sections).

The background informing this topic and existing renewable energy cooperation projects between China and the Philippines are addressed, and a Political, Economic, Social, Technological, Environmental, and Legal (PESTEL) analysis is adopted to illustrate the advantages and disadvantages of those factors in cooperation ( The Philippines—China Renewable Energy Cooperation Under Political, Economic, Social, Technological, Environmental, and Legal Analysis Section);

Finally, some feasible and promising suggestions are proposed to deal with emerging problems and opportunities in renewable cooperation between China and the Philippines under B&R ( Political, Economic, Social, Technological, Environmental, and Legal Recommendations Section).

Renewable Energy Development in the Philippines

Current status.

The Philippines stores rich renewable energy which also plays an important role in the energy supply of the country. As Table 1 shows, although the proportion of renewable energy in the total amount of installed capacity is only about 30% and there has been a slight downward trend in the last 3 years, the quantity produced is still steadily growing.

TABLE 1 . The Philippine installed capacity mix (MW) ( The Department of Energy, 2019 ).

Geothermal Energy

The Philippines is located in a tropical low-latitude area at the junction of Asia, Europe, and the Pacific plate, which means the country has rich geothermal energy resources. After many years of development, the installed capacity of geothermal power reached 1,944 MW in 2018, accounting for 13% of the world’s total, and ranking third after the United States and Indonesia ( Ratio et al., 2020 ).

Hydropower Energy

The Philippines has 421 rivers, numerous mountains, rugged terrain, and a rainy climate, which create abundant hydropower resources that contribute the largest portion of installed capacity generated by renewable energy. Although the Philippines already has some large-scale hydropower plants and has made achievements in the development of hydropower infrastructure, there is still 13,097 MW of undeveloped hydropower generation capacity remaining, according to an assessment by the Philippine Department of Energy ( The Department of Energy, 2019 ).

Solar Energy

With solar radiation of 4.0–6.0 kWh/m2/day, the Philippines has abundant solar energy resources which evenly distribute across the country and vary between 10 and 20% every month ( Sharma and Kolhe, 2020 ). Due to the continuous improvement of technology and efficiency of solar photovoltaic (PV) modules, the solar energy industry has achieved scale development and significantly reduced the costs of solar power generation ( Sharma and Kolhe, 2020 ). More and more residents and industrial sectors in the Philippines have started to use small-scale solar PV production.

Problem and Causes

The continuous economic expansion of the Philippines has brought serious problems in the form of insufficient energy supply ( Mondal et al., 2018 ). The Philippines’ GDP in 2018 grew by 6.2%, exceeding 6% for the seventh consecutive year ( GPD, 2019 ). However, more than 11% of the population has no electricity, and a higher proportion suffers from unreliable electricity supply ( Bertheau et al., 2020 ).

Huge reserves and the potential of renewable energy resources have not achieved a satisfying development in the Philippines.

The main reasons for the insufficient utilization of renewable energy, include the fact that the development of renewable energy requires high prepayment and technology costs ( Zafar et al., 2019 ). Moreover, hydropower and geothermal energy, which generate the most electricity, have a very long development cycle ( Barroco and Herrera, 2019 ). Moreover, the Philippines is unable to form an integrated power grid system, which impacts the sufficient transmission of electricity generated by renewable energy. The Philippine power supply system is also divided into “on-grid” and “off-grid” areas. The on-grid is supplied by two separate main power grids which lack a connection with each other. The off-grid covers these areas but suffers from insufficient power or even no power supply at all ( Bertheau et al., 2020 ).

Policies and Plans

The Philippine government has realized the importance of developing renewable energy and has formulated several policies and plans based on the focuses: 1) ensuring energy security, 2) achieving optimal energy pricing, 3) diversifying fuel sources, and 4) developing sustainable energy systems ( The Department of Energy, 2017 ). The National Renewable Energy Program (2011–2030) anticipates that the generation capacity of renewable energy will triple by 2030 ( Wang et al., 2020 ) This has lead to the development of policies including carbon taxes, the improvement of energy efficiency in both generation and consumption, diversification of the energy supply-mix ( Cabalu et al., 2015 ). Those policies and plans not only ensure energy security and reduced reliance on fossil energy they are also milestones in building a greener Philippines.

Renewable Energy Development Status in China

As the second-largest economy in the world, China has abundant renewable energy storage. By the end of 2019, the installed capacity of renewable energy in China was as high as 794.88 GW and has increased by 8.7% since 2018 ( Si et al., 2021 ). The current power generation capacity of each renewable energy source is shown in Figure 1 , and the current situation of China’s renewable energy is shown in Table 2 ( China Renewable Energy Engineering Institute, 2019 ). In 2013, China proposed the B&R initiative, which covers 65 countries in Asia, Africa, and Europe ( Wang et al., 2020 ). More importantly, promoting the green and low-carbon transformation of the energy structure of countries along the B&R is a core content of green construction in the area and a significant measure in improving the ecological environment and supporting global sustainable development ( Yang et al., 2021 ). As a key country along the Maritime Silk Road, the Philippines has also joined the Asian Infrastructure Investment Bank initiated by the Chinese government.

FIGURE 1 . Various types of power generation (A) installed capacity, and (B) proportion.

TABLE 2 . Status of types of renewable energy in China.

After decades of efforts, China has developed innovative approaches to energy and shared these experiences with other countries through the green cooperation of B&R to eliminate dependence on high-carbon growth models.

The advantages of the Chinese approach stem from it being a strong financial power. China has promoted the vigorous development of renewable energy, and in 2018 China became the world’s largest investor in renewable energy for the seventh consecutive year, an investment that accounts for almost one-third of the world’s total, reaching US $91.2 billion ( Si et al., 2021 ). Moreover, China’s renewable energy technology, manufacturing level, and high-quality production capacity have significantly improved in recent years, and a complete industrial chain with international advanced levels has been constructed in the renewable energy sector. This huge renewable energy product market has also contributed to the development of renewable energy worldwide.

In 2005, China enacted the Renewable Energy Law, quickly followed by more than 100 policies, regulating grid subsidies and special fund management measures, including guidance on promoting renewable energy consumption and other aspects as shown in Figure 2 ( China Renewable Energy Engineering Institute, 2019 ). The most important renewable energy plan of China is the 14th Five-year Plan (2021–2025). The key tasks of which include giving priority to the development of renewable energy based on market forces and low costs, systematically evaluating the development conditions and goals of various renewable energy resources, promoting renewable energy technologies and equipment to develop a relative industrial system, etc., ( Liu, 2019 ). In addition to the macro level, specific plans for different types of renewable energy exist that are international and jointly promote the construction of clean energy ( Liu, 2019 ).

FIGURE 2 . Renewable energy policy roadmap in China ( China Renewable Energy Engineering Institute, 2019 ). Abbreviations: National People’s Congress (NPC); State Council (SC); Renewable Energy (RE); Ministry of Finance (MOF); National Development and Reform Commission (NDRC); National Energy Administration (NEA); Exchange rate: 100 (CNY) = 15.4400 (USD) (Date: January 22, 2021).

The Philippines—China Renewable Energy Cooperation Under Political, Economic, Social, Technological, Environmental, and Legal Analysis

Existing cooperation.

China and the Philippines have a history of extensive cooperation in renewable energy, including hydropower, PV, biomass energy, and wind energy, as shown in Table 3 . This includes both the supply of existing equipment and Engineering Procurement Construction (EPC). This has greatly improved the utilization of hydroelectric and PV in the Philippines, and has made up for power shortages in some areas.

TABLE 3 . The Philippines—China renewable energy corporation projects.

Hydropower cooperation is the focus of the China-Philippines renewable energy cooperation agreement. Cooperative projects are mainly large-scale hydropower plants with an installed capacity of over 10 MW. Solar energy has now become the fastest-growing type of renewable energy in the Philippines, which has attracted many Chinese enterprises.

As one of the listed companies affiliated with the State Grid of China, the NARI Group owns several EPC projects of PV power stations in the Philippines. The Hengshun Group, a private company in China, signed an EPC contract of wind power and PV integration with Energy Logics Philippines, Inc. in 2016: the largest PV integration project to date in the Philippines.

Political, Economic, Social, Technological, Environmental, and Legal Analysis of Renewable Energy Cooperation

Under the intensifying forces of globalization and competition, PESTEL has recently evolved from PEST analysis, to consider the environmental and legal factors, with increased potential impact on businesses ( Thakur, 2021 ). The PESTEL analysis model is an effective tool for macro-environmental analysis that can not only analyze the external environment but also identify all forces that have an impact on the organization. This analysis mode mainly analyzes the investment environment of enterprises.

China and the Philippines have established diplomatic relations for 45 years. A mutual friendship formed after the election of Roberto Duterte to President of the Philippines in 2016. Building upon this preexisting relationship, China’s focus on green energy cooperation among countries means that it actively seeks energy cooperation partners in different regions. The Philippines is currently pursuing a green energy development model, implementing a large number of fiscal incentives to attract foreign investment in the renewable energy sector ( Cabalu et al., 2015 ).

Disadvantage

The relevant disputes between China and the Philippines in the South China Sea once froze the bilateral relationship. The current highly friendly relationship benefits from Duterte’s policy towards China, but this might change when Duterte’s term in office ends in 2022. Besides, the Philippines has serious political corruption problems and bureaucracy that may also lead to the unfair treatment of Chinese companies.

The Philippines is one of the most dynamic economies in the East Asia Pacific region. As a beneficiary of the power industry reform of the Philippines, the State Grid Corporation of China holds 40% of the National Grid Corporation of the Philippines. Meanwhile, Chinese energy enterprises have excellent brands and performance advantages. For example, as an active partner cooperating with the Philippines, China Energy Engineering Group Company has experience in power engineering projects and formed a complete industrial chain in international cooperation ( Shang et al., 2020 ).

In 2020, COVID- 19 pandemic caused a recession in the world economy and hindered international cooperation. In addition, the United States-China trade war has seriously affected the world market and greatly increased the trade barriers between economies. These international economic factors are detrimental to the cooperation between the two countries.

The overall economic level of the Philippines is not high, and the per capita GDP ranks 123rd in the world ( International Monetary Fund Philippine GDP per capita, 2019 ). Moreover, the industrial development level of the Philippines is relatively low, and public facilities such as transportation, electricity, and hydropower lag behind other countries. An out-of-date economy and lesser developed technical facilities make cooperation between the Philippines and other countries difficult.

China and the Philippines belong to the East Asian cultural circle and have a long history of cultural exchange. A Cultural Exchange Forum and a series of public welfare activities between the two countries were also held recently ( Sina News, 2018 ). After the COVID- 19 pandemic, China has repeatedly donated medical materials to the Philippines to jointly fight the epidemic.

The Philippines has an abundant labor force and a very young population structure in which the working-age population aged between 15 and 65 has reached 63.6%. In addition, English is the official language of the Philippines, and the literacy rate of Philippines residents is 96.4%, ranking among the highest in Asia ( Ministry of Commerce of the People’s Republic of China, 2019 ).

The domestic security situation of the Philippines is not favorable. There were 8,826 murders and 16,100 robberies in 2017, with 8.40 per 100,000 people ( Ministry of Commerce of the People’s Republic of China, 2019 ). There are also several armed rebel terrors groups.

The price levels and costs in the Philippines are also extremely high. The prices of vegetables and fruits, electricity, and hotel accommodation and meals are 3–4 times, 2–3 times, and 1–2 times higher than that of China, respectively ( Ministry of Commerce of the People’s Republic of China, 2019 ).

Technological

China and the Philippines are technically complementary in terms of energy development and power construction. China’s power technology is in the front ranks of the world and could help power development in the Philippines. For example, the advanced UHVDC power transmission technology could realize a sufficient power supply in the offshore islands, which is highly conducive to the formation of the power grid system in the Philippines. Meanwhile, China’s infrastructure construction, including 5G, the internet of things, and the industrial internet are also very advanced ( Yang et al., 2021 ). The Philippines also attaches great importance to the development of science and technology through active cooperation with technology-developed countries in engineering and scientific projects via higher education.

Due to the limitations of technology and financial resources, the level of large-scale projects independently constructed by the Philippines is very limited. Hence, many projects have been completed with capital and technologies from other countries. Chinese enterprises may lack the most advanced technology and experience in geothermal energy cooperation due to the lack of domestic geothermal resources.

The risks affecting electricity technical standards of design and construction cannot be ignored. The Philippines mainly adopts American standards which are different from those of China and lead to the extension of design and approval time.

Environment

China is a maritime neighbor of the Philippines, and the local time of the Philippines is consistent with Beijing time, which is convenient for cooperation and communication.

Due to its fragile climate and frequent geological disasters, the Philippines is frequently affected by natural disasters resulting in a great loss of human life and property ( Bollettino et al., 2020 ). Besides, the construction of hydropower stations could adversely affect wildlife and plants and lead to geological disasters. Local people and environmental protection organizations are very opposed to the construction of hydropower stations and the development of geothermal energy, which may greatly impact energy cooperation.

China and the Philippines issued the “Renewable Energy Law” in 2005 and 2008, respectively, to vigorously develop renewable energy and ensure energy security and the optimization of the ecological environment. Foreign investment in biomass and garbage power generation projects had a restriction of 40% lifted in November of 2019 after an announcement by the Philippine government. It is anticipated that other renewable energy projects will be further opened to foreign investment in the future ( The Department of Energy Administrative Order, 2020 ).

According to Philippine law, foreign investors are prohibited from buying land ( The Department of Energy Administrative Order, 2020 ). In addition, the Philippines has strict controls over work visas for Chinese, which is not conducive to management and technical personnel traveling there from China. Furthermore, as the main form of contracted projects between Chinese enterprises and the Philippines, government projects can only be established after being approved by the Philippine National Economic Development Agency.

Political, Economic, Social, Technological, Environmental, and Legal Recommendations

First, the Philippines and China should make the most of the existing mutual friendly diplomatic relationship to actively develop cooperation. The B&R and the China-ASEAN Free Trade Area have brought more opportunities and favorable conditions for renewable energy cooperation between the two countries. In terms of disputes in the South China Sea, it is the consensus and commitment of China and the Philippines to settle through negotiation and properly manage their relevant dispute.

Secondly, the renewable energy development strategy could be deepened in the two countries respectively. China should consider renewable energy as a new orientation of developing export trade and investment outward, and actively guide and support overseas cooperation. The Philippines could absorb advanced foreign renewable energy technologies in grid construction while mobilizing domestic resources to develop renewable energy.

With the guidance of the B&R initiative and the help from the Asian Infrastructure Investment Bank, the Philippines could actively carry out infrastructure construction to improve the business environment. In terms of offshore islands, the construction of renewable energy power plants and grids would solve electricity shortages.

Hydropower and geothermal power generation are the main areas of international cooperation in the Philippines. The EPC mode could be an ideal choice in cooperation, which is relatively fixed, and the implementation period is not long. Chinese companies could integrate the upstream and downstream of the industrial chain systematically to achieve sufficient cooperation and expand the scale and benefits of collaboration.

The two countries could continue to carry out cultural exchange under the background of B&R and promote non-government exchange. In addition, China and the Philippines always adhere to the coexistence of diversified culture, mutual learning, and cooperation for shared benefits. Therefore, Chinese companies participating in cooperation should pay attention to local cultural differences, and respect the local customs, religions, and living habits of the Philippines. Besides, the Philippine government needs to increase public security management through the reduction of crime rate, strictly control the possession of guns, and standardize its application administrative procedures.

Firstly, China is an advantageous partner in assisting the Philippines to form a complete power grid that especially aims to increase the power supply of offshore islands. To reduce the technical risk, research and exploitation in major technology should be strengthened. Making good use of a contract to constraint risk, promoting project supervision and construction quality should be the focus of project management.

Secondly, great attention should also be paid to the integration of power standards with international standards. Due to the different situations in each country, integration should not aim to achieve the unity of technical standards but to learn from the international advanced technical standards and increase public knowledge of China’s working practices to continuously optimize and update standards.

Due to the frequent occurrence of natural disasters and tropical epidemic diseases in the Philippines, contractors should pay close attention to local news and take preventive measures to prevent personnel and property losses.

Actively fulfilling social responsibility and strengthening environmental awareness is of great significance, because they develop the local economy and improve local people’s livelihoods. Through appropriate publicity in a local area, the public could be told more about the cooperative project, and gain an understanding of the fact that they will directly experience an improvement in quality of life quality from these projects. This would improve the enterprise’s local popularity and form a positive corporate image.

On the governmental level, an agreement focused on the strategic cooperation of renewable energy and based on the national strategy and security of both two countries could be reached, which may include investment, technology cooperation, grid construction, and trade. Furthermore, governments of China and the Philippines could establish a unified and effective platform to share renewable cooperative information, corresponding policies, and administrative procedures to solve the difficulty of information collection and nontransparent policies faced by potential cooperators or contractors.

In terms of enterprises, Chinese organizations need to fully understand Philippine laws and regulations to ensure they operate legally, including visas, environmental protection, land, and localized employment regulations. Moreover, the restriction of the foreign investment ratio of renewable energy projects should be studied seriously to maximize the profit of the enterprises in accordance with the laws of the Philippines.

This paper is the first to undertake a systematic study of renewable energy cooperation between China and the Philippines under B&R, and draws the following crucial conclusions:

Firstly, the cooperation between China and the Philippines in renewable energy is a mthod of building a greener Philippines and protecting the environment. The coexistence of abundant but undeveloped renewable energy resources and the shortage of electricity supply, especially in the offshore islands, requires deep cooperation with China, as it has superior technological and extensive experience in grid construction. Among various renewable energy, hydropower and geothermal powers are major cooperative areas, in terms of the status of the Philippines. How to explore and utilize renewable energy more economically and efficiently, and realize a sufficient electricity supply are important factors in alleviating dependence on imported fossil fuel energy, a will form a top priority of any cooperative agreement. In addition, the two countries can use the opportunity of renewable energy cooperation to promote cooperation in other industries and achieve mutual benefit and win-win results between the two countries.

Secondly, renewable energy cooperation is the focus of energy cooperation in any B&R initiative. Moreover, a Regional Comprehensive Economic Partnership was established in 2020 and has eliminated trade barriers between Asia-Pacific countries and ASEAN countries. The combination of these initiatives and agreements presents an unprecedented opportunity for China and the Philippines to develop renewable energy cooperation. However, the outbreak of the United States-China trade war and the ongoing COVID- 19 pandemic have brought unprecedented challenges to such potential cooperation initiatives. In response to opportunities and challenges and to achieve a win-win situation, China and the Philippines need to strengthen political and economic cooperation and promote corresponding policies.

Thirdly, a cooperative agreement focused on strategic cooperation concerning renewable energy that is based on national strategy and the security of both two countries may include investment, technology cooperation, grid construction, and trade for renewable energy infrastructure. Furthermore, the Chinese and the Philippine governments could establish a unified and effective platform to share renewable cooperative information, corresponding policies, and administrative procedures to solve the difficulties of collecting information and nontransparent policies faced by potential cooperators or contractors.

Finally, although the disputes between China and the Philippines in the South China Sea once impacted this bilateral relationship seriously, the current friendly relationship has lasted 5 years, creating a positive and timely opportunity for cooperation between the two countries.

Author Contributions

XL: Conceptualization, Writing- Reviewing and Editing. HW: Writing- Original draft preparation, Investigation. YL: Writing- Reviewing and Editing. WL: Supervision, Resources.

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher’s Note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Acknowledgments

The authors acknowledge the support of the Talents Training Program of Kunming University of Science and Technology (KKZ3201524007).

Anand, K., Md Nishat, A., and Shekhar, K. (2021). Sliding Mode Controller Design for Frequency Regulation in an Interconnected Power System. Prot. Control. Mod. Power Syst. 6 (1), 77–88. doi:10.1186/s41601-021-00183-1

Google Scholar

Barroco, J., and Herrera, M. (2019). Clearing Barriers to Project Finance for Renewable Energy in Developing Countries: A Philippines Case Study. Energy Policy. 135, 111008. doi:10.1016/j.enpol.2019.111008

CrossRef Full Text | Google Scholar

Bertheau, P., Dionisio, J., Jütte, C., and Aquino, C. (2020). Challenges for Implementing Renewable Energy in a Cooperative Driven off- Grid System in the Philippines. Environ. Innovation and Soci. Trans. 35, 333–345. doi:10.1016/j.eist.2019.03.002

Bollettino, V., Alcayna-Stevens, T., Sharma, M., Dy, P., Pham, P., and Vinck, P. (2020). Public Perception of Climate Change and Disaster Preparedness: Evidence From the Philippines. Clim. Risk Management. 30, 100250. doi:10.1016/j.crm.2020.100250

Cabalu, H., Koshy, P., Corong, E., Rodriguez, U.-P. E., and Endriga, B. A. (2015). Modelling the Impact of Energy Policies on the Philippine Economy: Carbon Tax, Energy Efficiency, and Changes in the Energy Mix. Econ. Anal. Pol. 48, 222–237. doi:10.1016/j.eap.2015.11.014

China Renewable Energy Engineering Institute (2019). China Renewable Energy Development Report. Available at: http://www.creei.cn/portal/article/index/id/25365.html. 2020 (Accessed November 26, 2020).

Feng, T. T., Gong, X. L., Guo, Y. H., Yang, Y. S., Pan, B. B., Li, S. P., et al. (2020). Electricity Cooperation Strategy Between China and ASEAN Countries Under‘ the Belt and Road’. Energy Strategy Reviews. 30, 100512. doi:10.1016/j.esr.2020.100512

GPD (2019). GDP (Current US$) – Philippine GDP . World Development Indicators database . Available at: https://www.worldbank.org/cn/country/Philippine (Accessed November 19, 2020).

Gullberg, A. T., Ohlhorst, D., and Schreurs, M. (2014). Towards a Low Carbon Energy Future - Renewable Energy Cooperation between Germany and Norway. Renew. Energ. 68, 216–222. doi:10.1016/j.renene.2014.02.001

Indeo, F. (2019). ASEAN- EU Energy Cooperation: Sharing Best Practices to Implement Renewable Energy Sources in Regional Energy Grids. Global Energy Interconnection. 5 (2), 393–401.

International Monetary Fund Philippine GDP per capita (2019). International Monetary Fund Philippine GDP Per Capita. Available at: https://www.imf.org/external/index.htm (Accessed December 20, 2020).

Liu, J. (2019). China's Renewable Energy Law and Policy: A Critical Review. Renew. Sustainable Energ. Rev. 99, 212–219. doi:10.1016/j.rser.2018.10.007

Marquardt, J., and Delina, L. L. (2019). Reimagining Energy Futures: Contributions From Community Sustainable Energy Transitions in Thailand and the Philippines. Energ. Res. Soc. Sci. 49, 91–102. doi:10.1016/j.erss.2018.10.028

Mehdi, T., and Mehdi, N. (2020). Human Reliability Analysis in Maintenance Team of Power Transmission System protection. Prot. Control. Mod. Power Syst. 5 (4), 270–282.

Ministry of Commerce of the People's Republic of China (2019). Guide for Foreign Investment and Cooperation Countries (Regions)- Philippines. Available at: http://www.mofcom.gov.cn/mofcom/typt.shtml (Accessed December 25, 2020).

Mohan, M. (2021). A Comprehensive Review of DC Fault protection Methods in HVDC Transmission Systems. Prot. Control. Mod. Power Syst. 6 (1), 1–20.

Mondal, M. A. H., Rosegrant, M., Ringler, C., Pradesha, A., and Valmonte-Santos, R. (2018). The Philippines Energy Future and Low-Carbon Development Strategies. Energy. 147, 142–154. doi:10.1016/j.energy.2018.01.039

Ratio, M. A., Gabo- Ratio, J. A., and Fujimitsu, Y. (2020). Exploring Public Engagement and Social Acceptability of Geothermal Energy in the Philippines: A Case Study on the Makiling- Banahaw Geothermal Complex. Geothermics. 85, 101774. doi:10.1016/j.geothermics.2019.101774

Sasmita, P., and Sidhartha, P. (2021). Application of a Simplified Grey Wolf Optimization Technique for Adaptive Fuzzy PID Controller Design for Frequency Regulation of a Distributed Power Generation System. Prot. Control. Mod. Power Syst. 6 (1), 21–36.

Satish, K. I., and Vinod, K. T. (2020). Optimal Integration of DGs into Radial Distribution Network in the Presence of Plug- in Electric Vehicles to Minimize Daily Active Power Losses and to Improve the Voltage Profile of the System Using Bioinspired Optimization Algorithms. Prot. Control Mod. Power Syst. 5 (1), 21–35.

Shang, T., Liu, P., and Guo, J. (2020). How to Allocate Energy-Saving Benefit for Guaranteed Savings EPC Projects? A Case of China. Energy. 191, 116499. doi:10.1016/j.energy.2019.116499

Sharma, A., and Kolhe, M. (2020). Techno- Economic Evaluation of PV Based Institutional Smart Microgrid under Energy Pricing Dynamics. J. Clean. Prod. 264, 121486. doi:10.1016/j.jclepro.2020.121486

Si, S., Lyu, M., Lin Lawell, C.-Y. C., and Chen, S. (2021). The Effects of Environmental Policies in China on GDP, Output, and Profits. Energ. Econ. 94, 105082. doi:10.1016/j.eneco.2020.105082

Sina News (2018). The Largest Non- Governmental Cultural Exchange Event in the History of China and the Philippines Former Philippine President: Thank You China!. Available at: http://k.sina.com.cn/article_3974550866_ece6d55200100bv9g.html (Accessed December 22, 2020).

Suryanarayana, G., and Saumendra, S. (2020). A Novel Complex Current Ratio- Based Technique for Transmission Line protection. Prot. Control. Mod. Power Syst. 5 (3), 239–247.

Thakur, V. (2021). Framework for PESTEL Dimensions of Sustainable Healthcare Waste Management: Learnings From CO VID- 19 Outbreak. J. Clean. Prod. 287, 125562. doi:10.1016/j.jclepro.2020.125562

PubMed Abstract | CrossRef Full Text | Google Scholar

The Department of Energy Administrative Order (2020). The Department of Energy Administrative Order. Available at: https://www.doe.gov.ph/laws- and- issuances/administrative- order (Accessed November 05, 2020).

The Department of Energy (2017). Draft National Renewable Energy Program Overview. Available at: https://www.doe.gov.ph/presentations (Accessed November 05, 2020).

The Department of Energy (2019). Biomass Sector Roadmap. Available at: https://www.doe.gov.ph/presentations (Accessed November 05, 2020).

Wang, C., Wood, J., Geng, X. R., Wang, Y. L., Q iao, C. Y., and Long, X. L. (2020). Transportation CO2 Emission Decoupling: Empirical Evidence from Countries along the belt and Road. J. Clean. Prod. 263, 121450. doi:10.1016/j.jclepro.2020.121450

Yang, B., Swe, T., Chen, Y., Zeng, C., Shu, H., Li, X., et al. (2021). Energy Cooperation between Myanmar and China under One Belt One Road: Current State, Challenges and Perspectives. Energy. 215, 119130. doi:10.1016/j.energy.2020.119130

Zafar, M. W., Shahbaz, M., Hou, F., Sinha, A., and Sinha, A. (2019). From Nonrenewable to Renewable Energy and its Impact on Economic Growth: The Role of Research & Development Expenditures in Asia-Pacific Economic Cooperation Countries. J. Clean. Prod. 212, 1166–1178. doi:10.1016/j.jclepro.2018.12.081

Keywords: the belt and road, the Philippines-China cooperation, renewable energy, PESTEL analysis, renewable energy cooperation

Citation: Li X, Wang H, Lu Y and Li W (2021) A Critical Survey on Renewable Energy Applications in the Philippines and China: Present Challenges and Perspectives. Front. Energy Res. 9:724892. doi: 10.3389/fenrg.2021.724892

Received: 15 June 2021; Accepted: 19 July 2021; Published: 30 July 2021.

Reviewed by:

Copyright © 2021 Li, Wang, Lu and Li. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Wanlin Li, [email protected]

This article is part of the Research Topic

Advanced Optimization and Control for Smart Grids with High Penetration of Renewable Energy Systems

• Original article
• Open access
• Published: 09 January 2018

A real options approach to renewable electricity generation in the Philippines

• Casper Boongaling Agaton   ORCID: orcid.org/0000-0003-1153-262X 1 &
• Helmut Karl 2  

Energy, Sustainability and Society volume  8 , Article number:  1 ( 2018 ) Cite this article

31k Accesses

21 Citations

5 Altmetric

Metrics details

The Philippines is making a significant stride to become energy independent by developing more sustainable sources of energy. However, investment in renewable energy is challenged by competitive oil prices, very high investment cost for renewable energy, and high local electricity prices. This paper evaluates the attractiveness of investing in renewable energy sources over continue using oil for electricity generation.

This paper uses the real options approach to analyze how the timing of investment in renewable energy depends on volatility of diesel price, electricity price, and externality for using oil.

The result presents a positive net present value for renewable energy investment. Under uncertainty in oil prices, dynamic optimization describes how waiting or delaying investment in renewables incurs loses. Decreasing the local electricity price and incorporating negative externality favor investment in renewable energy over continuing the use of oil for electricity generation.

Conclusions

Real options approach highlights the flexibility in the timing of making investment decisions. At the current energy regime in the Philippines, substituting renewable energy is a better option than continue importing oil for electricity generation. Policies should aim at supporting investment in more sustainable sources of energy by imposing externality for using oil or decreasing the price of electricity.

Environmental problems associated with emissions from fossil fuel, along with limited supply, volatile prices, and energy security, prompted developed and developing countries to find more reliable and sustainable sources of energy. Renewable energy (RE) sources, being abundant, inexhaustible, cleaner, and readily available, emerge as a promising alternative energy source. According to International Energy Agency (IEA), RE accounted to 13.7% of the world energy generation mix in 2015 [ 1 ]. With a rapid decline in RE costs, this percentage mix is expected to double by 2040 [ 2 ]. In the Philippines, the development and optimal use of RE resources is an essential part of the country’s low emission strategy and is vital to addressing climate change, energy security, and access to energy [ 3 ]. In 2015, renewable energy accounts to 25% of the country’s total electricity generation mix, only 1% from wind and solar energy [ 4 ]. Since the country is highly dependent on imported fossil fuels, sudden changes in the price of fuels in the world market may eventually affect the country’s energy security. Renewable energy serves as a long-term solution by introducing localized RE sources. However, despite the country’s huge potential for RE generation, investments in RE projects are challenged by competitive prices of fossil fuels, more mature technology for fossil fuels, and very high investment cost for renewable energy. These give us the motivation to make a study that analyzes the attractiveness of RE investments to address the country’s concern on energy sufficiency and sustainability.

One of the most common techniques in analyzing investment projects is the net present value (NPV). This technique is widely used by developers, financial institutions, and government agencies under the condition of definite cash flow. Since RE investment in emerging economies involves high risk from volatile energy prices and changing RE technologies, NPV undervalues investment opportunities and thus considered inappropriate for assessing RE projects in developing countries including the Philippines [ 5 ]. Real options approach (ROA) overcomes this limitation as it combines risks and uncertainties with flexibility in the timing of investment as a potential factor that gives additional value to the project [ 6 ]. Recent studies use ROA renewable energy investment particularly for wind, solar photovoltaic (PV), hydropower, concentrated solar power (CSP), and combination (hybrid) of RE with uncertainties in non-RE cost, certified emission reduction (CER), feed-in tariff (FIT), energy production, operations and maintenance (O&M) cost, research and development (R&D) grants, production tax credit (PTC), RE credit (REC), among others (see Table  1 ).

This paper contributes to the existing literature by proposing a ROA framework for analyzing RE projects for developing countries, particularly, island countries that are highly dependent on imported oil for electricity generation. While previous studies proposed a full system switch to RE [ 7 ] or applied the ROA model to large-scale RE projects [ 8 , 9 , 10 , 11 ], this study takes the case of Palawan island in the Philippines and focuses on a smaller scale project which is particularly more realistic to developing countries. Whereas previous works’ approaches used coal and gas for fuel price uncertainty [ 7 , 9 , 10 , 12 ], this work uses uncertainty in oil prices as the world energy mix is dominated by liquid fuel, more developing countries are dependent on imported oil, and that investments in renewable energy is affected more by volatility in oil prices than coal prices. Finally, this paper proposes an externality tax for using fossil fuels as it more applicable in developing countries than introducing CER price, PTC, REC, CO 2 price, and emission/externality cost as proposed in previous works [ 7 , 9 , 10 , 13 , 14 ].

Applying ROA, this study aims to evaluate whether investing in RE is a better option than continue using diesel for electricity generation by considering various uncertainties in diesel fuel price, local electricity prices, and imposing externality tax for using diesel. This finally aims to recommend various government actions to address environmental problem, supply chain, and national security regarding energy.

Real options approach

Myers [ 15 ] first referred ROA or real options valuation as the application of option pricing theory to valuate non-financial or “real” assets. Real option itself is “as the right, but not the obligation, to take an action (e.g., deferring, expanding, contracting or abandoning) at a predetermined cost, called exercise price, for a predetermined period of time – the life of the option” [ 16 ]. Investment decisions, in the real world, have main characteristics: irreversible, high risk and uncertain, and flexible [ 17 ]. These characteristics are not captured by traditional methods of valuation, such as NPV, discounted cash flow (DCF), internal rate of return (IRR), and return on investment (ROI) leading to poor policy and investment decisions. ROA, on the other hand, combines uncertainty and option flexibility which characterize many investment decisions in the energy sector.

This research applies ROA to analyze investment decisions whether to continue using diesel for electricity generation or invest in RE. We use the uncertainty in diesel prices as a main factor that affects investment decisions. Using dynamic optimization, we evaluate the maximized value of investment at each price of diesel, identify the trigger price for shifting technology from diesel-based electricity to RE, and analyze the value of waiting or delaying to invest in RE. Finally, we incorporate sensitivity analyses with respect to electricity prices and externality tax for using diesel.

• Dynamic optimization

We follow the method described by Dixit and Pindyck [ 18 ] and adopt the work of Detert and Kotani [ 7 ] on optimizing investment decision under uncertainty using dynamic programming. In this research, we describe a model of an investor that identifies the optimal value of either investing in RE or continue using diesel for electricity generation as shown in Eq.  1 (see Table  2 for the list of variables and parameters).

Using this model, we determine the option value, V D , t , by maximizing the investment at each price of diesel, D , from 0 to US$1000/barrel, for each investment period, t . We set the dynamic optimization process to 40 years which represent a situation where an investor is given a period to make an investment decision. After that period, he has no other option but to continue using diesel for electricity generation. The choice is valued for another 25 years to represent the lifetime of power plant using diesel. We set the value of T R to 25 years to represent the number of years of electricity generation using RE. Finally, we solve the problem backwards using dynamic programming from terminal period [ 7 , 19 ]. The uncertainty in diesel prices in Eqs.  2 and 3 as well as the Monte Carlo simulation in the dynamic optimization process is discussed in the next subsection.

Stochastic prices and Monte Carlo simulation

In line with the previous studies, we assume that the price of diesel is stochastic and follow geometric Brownian motion (GBM) [ 20 , 21 , 22 ]. Dixit and Pindyck [ 18 ] present the stochastic price process as

where α and σ represent the mean and volatility of diesel price, dt is the time increment, and dz is the increment of Wiener process equal to \( {\varepsilon}_t\sqrt{dt} \) such that ε t ~ N (0, 1). Using Ito’s lemma, we arrive at

We approximate Eq.  6 in discrete time as

To determine the drift and variance of P , we use the Augmented Dickey-Fuller (ADF) unit root test using the following regression equation

where \( c(1)=\left(\alpha -\frac{1}{2}{\sigma}^2\right)\Delta t \) and \( {e}_t=\sigma {\varepsilon}_t\sqrt{\Delta t} \) . We then estimate the maximum likelihood of the drift \( \alpha =\mu +\frac{1}{2}{s}^2 \) and variance σ  =  s , where α is the mean and s is the standard deviation of the series p t  −  p t  + 1 [ 23 ].

In this research, we use the annual prices of diesel from 1980 to 2016. The result of ADF test as shown in Table  2 implies that the null hypothesis that p t has a unit root at all significant levels cannot be rejected. Therefore, P conforms GBM. We estimate the parameters α  = 0.007614 and σ  = 0.358889 and use in identifying stochastic prices of diesel under GBM (Table  3 ).

We use the Monte Carlo simulation to compute the expected net present value of electricity generation using diesel in Eqs.  2 and 3 . First, we approximate a vector of potential prices of diesel using the stochastic prices of GBM as follows:

This equation illustrates that the previous price affects the current price of diesel. Second, from the initial price of diesel, P D , 0 , we estimate the succeeding prices of diesel in each period using Eq.  9 . We incorporate these prices in Eq. 2 and calculate the present values of using diesel for electricity generation. Finally, we estimate the expected net present value at each initial price node i and repeat the whole process in a sufficiently large number of J  = 10000 times and take the average as given by the equation

Trigger price of diesel

Dynamic optimization process in the previous sections generates the maximized option values of investment. From these simulation results, we identify the trigger price of diesel for switching to RE as follows

where \( {\widehat{P}}_D \) is the trigger price of diesel or the minimum price where the option value in the initial period V 0 ( P D , t ) is equal to the option value in the terminal period of investment \( {V}_{{\mathrm{T}}_R}\left({P}_{D,\mathrm{t}}\right) \) [ 7 , 18 , 24 ]. From the given equation, we define trigger price as the minimum price of diesel that maximizes the profit of shifting the source of electricity from diesel power plant to RE.

Data and scenarios

To determine a suitable set of parameter values for the baseline scenario, we use data from various sources that nearly reflects the investment environment for renewable energy project in Palawan. This is the largest island province in the Philippines composed of 1780 islands and islets that are currently not connected to the national grid and only depend on imported diesel and bunker fuel. The recent Calatagan Solar Farm project in Batangas is set as a benchmark of the data for investment in RE, as this project is the latest RE project in the Philippines and has similar geographic features with Palawan; hence, investment cost estimations are up-to-date and relatively comparable [ 25 ]. This 63.3 MW solar farm, covering a total area of 160 ha, projects to generate 88,620 MWh of electricity per year. It costs US$120 million and will operate for at least 25 years. We use the data from Palawan Electric Cooperative (PALECO) [ 26 ] to approximate the local electricity price and the quantity and costs of generating electricity from diesel.

Electricity prices in the Philippines varies from island to island depending on the source of energy, as well as various charges including the generation, transmission, distribution, metering, and loss. In Palawan, effective power rates also vary across different municipalities [ 26 ]. We employ these variations in the electricity price scenario by changing the electricity price in the baseline model. In this scenario, we aim to describe how policy in imposing electricity price ceiling or price floor affects the investment decisions particularly in introducing RE as a source for electricity generation.

Lastly, we consider the externality tax of electricity generation from diesel. This value represents the negative externality including, but not limiting to, health and environmental problems associated with combustion of diesel. We use the data of the estimated average external costs for electricity generation technologies from European Environmental Agency (EEA) [ 27 ]. For this scenario, we include externality costs, tax for estimating the net present value of using diesel in Eqs.  2 and 3 . We arbitrarily assign values, between 0 (for baseline) to US$ 80/MWh, which are lower than those reported in literature to describe a more realistic condition. We assume that RE source, particularly solar PV, produces minimal or nearly no externality.

Results and discussion

Baseline scenario.

Figure  1 and Table  4 show the result of dynamic optimization at the baseline scenario. The first point of interest is the positive net present value of RE. This implies that, using the traditional valuation method, renewable project is a good investment in the island of Palawan. This result is evident as the installation of solar energy projects grows rapidly in the recent years. In 2016, there are already 538.45 MW installed capacity of solar projects from the 4399.71 potential capacity in the whole country [ 25 ]. Caution must be applied as net present value is not the sole determinant of investment in ROA. The optimal timing that maximizes the value of investment opportunity under uncertainty must also be accounted for [ 18 ].

Option values at the baseline scenario. Legend: base_0: option values of energy investment at the initial period; base_T: option values of energy investment at the terminal period

Figure  1 shows the dynamics of the option values at different initial prices of diesel. Result shows that the option values decrease over diesel price as the cost of generating electricity increases with fuel price. The trigger price as indicated by the intersection of option value curves indicates the minimum price of diesel that maximizes the decision of shifting from diesel based to RE generation. The result in the baseline scenario at US$168/barrel is higher than the current price at US$101.6/barrel. Intuitively, this implies that waiting to invest in RE is a better option than investing at the current price of diesel. However, the value of waiting to invest as describe by the distance between option value curves from initial to terminal period is negative. As seen in Table  4 , the option value at the current price of diesel at the initial period of investment is US$141.38 million and decreases to 104.97 million at the terminal period. This results to a US$36.41 million loss from delaying or waiting to invest. This implies that waiting to invest in RE incurs losses.

Electricity price scenario

This scenario describes how adjusting the local electricity price affects the option values and the trigger price. Figures  2 and 3 show the dynamics of option values with increasing and decreasing electricity prices decreasing electricity prices (see Additional file 1 Table S2 for dynamic optimization result). Result shows that the option values shift upwards with increasing electricity prices. This shows that at higher electricity prices, the value of either renewable energy or diesel-based electricity both increases. However, the trigger prices of diesel also increase to US$172/barrel at US$220/MWh and US$185/barrel at US$250/MWh from the baseline electricity price of US$202/MWh. This suggests that increasing the electricity price encourages waiting or delaying to invest in RE.

Option values at increasing electricity price scenario. Legend: base_0: option values of energy investment at the initial period; base_T: option values of energy investment at the terminal period; elec+1_0: option values at 10% higher electricity price than the base at the initial period; elec+1_T: option values at 10% higher electricity price than the base at the terminal period; elec+2_0: option values at 25% higher electricity price than the base at the initial period; elec+2_T: option values at 25% higher electricity price than the base at the terminal period

Option values at decreasing electricity price scenario. Legend: base_0: option values of energy investment at the initial period; base_T: option values of energy investment at the terminal period; elec−1_0: option values at 10% lower electricity price than the base at the initial period; elec−1_T: option values at 10% lower electricity price than the base at the terminal period; elec−2_0: option values at 25% lower electricity price than the base at the initial period; elec−2_T: option values at 25% lower electricity price than the base at the terminal period; elec−3_0: option values at 40% lower electricity price than the base at the initial period; elec−3_T: option values at 40% lower electricity price than the base at the terminal period

On the other hand, decreasing electricity prices shifts the option value curves downwards and decreasing the trigger price of diesel. This result is apparent as decreasing electricity price results to a lower revenue and thus lower profit for both options. The trigger prices of diesel decrease to US$160/barrel at US$180/MWh, US$150/barrel at US$150/MWh, and US$139/barrel at US$120/MWh price of electricity (Figs.  3 and 4 ). This suggests that lowering the electricity price decreases the timing to invest in renewable energy. Further, the option values become negative at electricity price below US$120/MWh. This implies that policy makers or power producers must not set an electricity price below US$120/MWh, as this will result to a loss for producing electricity from diesel as well as a negative investment for RE.

Trigger prices of diesel over electricity price

Externality scenario

This scenario describes how inclusion of externality tax from combustion of diesel affects the option values and triggers prices in investment in RE projects. The result in Fig.  5 (see Additional file 1 Table S3 for dynamic optimization result) shows that option values shift to the left. First, this implies that imposing externality tax decreases the revenue from electricity generation using diesel and thus decreasing the option values. Second, the unchanged lower boundary of the curves implies externality does not affect the value of investment in renewable energy. This is due to our assumption that electricity generation from RE produces no externality.

Option values at negative externality scenario. Legend: base_0: option values of energy investment with no externality at the initial period; base_T: option values of energy investment with no externality at the terminal period; ex1_0: option values at 20$/MWh externality cost at the initial period; ex1_T: option values at 20$/MWh externality cost at the terminal period; ex2_0: option values at 40$/MWh externality cost at the initial period; ex2_T: option values at 40$/MWh externality cost at the terminal period; ex3_0: option values at 60$/MWh externality cost at the initial period; ex3_T: option values at 60$/MWh externality cost at the terminal period; ex3_0: option values at 80$/MWh externality cost at the initial period; ex4_T: option values at 80$/MWh externality cost at the terminal period

With externality, the trigger prices of diesel decrease to US$140/barrel at US$20/MWh, US$111/barrel at US$40/MWh, US$82/barrel at US$60/MWh, and US$54/barrel at US$80/MWh externality cost (Figs.  5 and 6 ). This implies that imposing externality tax for diesel makes investment in RE more optimal than continue using diesel. Finally, the threshold of externality cost is US$46.55/MWh at the current diesel price of US$101.64/barrel. This is the minimum externality cost that favors immediate investment in RE than continue using diesel.

Trigger prices of diesel over negative externality

We evaluate investment environments and decision-making process for substituting diesel power plant with RE for electricity generation in the Philippines. Using real options approach under uncertainty in diesel prices, we identify the option values, trigger prices of diesel, and value of waiting to invest in RE. We analyze the sensitivity of investment decisions with respect to various electricity prices and addition of externality tax for using diesel.

ROA highlights the flexibility in the timing of making investment decisions. Our analyses conclude that for a developing country that is highly dependent on imported fuel, shifting to RE is a better option than continue using imported diesel. Policies should aim at supporting investment in more sustainable sources of energy by imposing externality for using fossil-based fuel or decreasing the price of electricity. This may negatively affect the power producers but encourage them to shift from diesel to renewable energy.

We summarized a unique approach to energy investment by replacing diesel with RE for electricity generation. We believe that the ROA framework introduced in this research is a good benchmark for further application. First, ROA may take account of environmental and social costs. This may include the cost of deforestation for solar farm, wildlife and habitat loss, air and water pollution, damage to public health, and loss of jobs. Finally, analyzing investment decisions with several RE resources includes dynamic optimization with different scenarios of generation mix from various RE sources. We are optimistic that this research becomes one-step forward for further analysis of investment in more sustainable sources of energy.

Abbreviations

Augmented Dickey-Fuller

Certified emission reduction

Concentrated solar power

Discounted cash flow

European Environmental Agency

Feed-in tariff

Geometric Brownian motion

International Energy Agency

Internal rate of return

Net present value

Operations and maintenance

Palawan Electric Cooperative

Production tax credit

Solar photovoltaic

Research and development

• Renewable energy

Renewable energy credit

Return on investment

IEA (2017) Key world energy statistics. International Energy Agency. https://www.iea.org/publications/freepublications/publication/KeyWorld2017.pdf Accessed 12 Oct 2017

BNEF (2017) New energy outlook 2017. Bloomberg New Energy Finance. https://data.bloomberglp.com/bnef/sites/14/2017/06/BNEF_NEO2017_ExecutiveSummary.pdf?elqTrackId=431b316cc3734996abdb55ddbbca0249&elq=0714ab8b3c51467a8b29e864d6fff67a&elqaid=7785&elqat=1&elqCampaignId = Accessed 12 Oct 2017

DOE (2012) Philippine Energy Plan 2012-2030. Philippines’ Department of Energy. https://www.doe.gov.ph/sites/default/files/pdf/pep/2012-2030_pep.pdf Accessed 09 Sept 2017

DOE (2016) Philippine Power Statistics 2015. Philippines’ Department of Energy. https://www.doe.gov.ph/sites/default/files/pdf/energy_statistics/power_statistics_2015_summary.pdf Accessed 01 Jan 2017

Kim K, Park H, Kim H (2017) Real options analysis for renewable energy investment decisions in developing countries. Renew Sust Energ Rev 75:918–926. https://doi.org/10.1016/j.rser.2016.11.073

Article   Google Scholar  

Brach MA (2003) Real options in practice. John Wiley & Sons, Inc., Hoboken, New Jersey

Google Scholar  

Detert N, Kotani K (2013) A real options approach to energy investments in Mongolia. Energy Policy 56:136–150. https://doi.org/10.1016/j.enpol.2012.12.003

Weibel S, Madlener R (2015) Cost-effective design of ringwall storage hybrid power plants: a real options analysis. Energy Convers Manag 103:871–885. https://doi.org/10.1016/j.enconman.2015.06.043

Wesseh PK Jr, Lin B (2015) Renewable energy technologies as beacon of cleaner production: a real options valuation analysis for Liberia. J Clean Prod 90:300–310. https://doi.org/10.1016/j.jclepro.2014.11.062

Zhang MM, Zhou P, Zhou DQ (2016) A real options model for renewable energy investment with application to solar photovoltaic power generation in China. Energy Econ 59:213–226. https://doi.org/10.1016/j.eneco.2016.07.028

Kitzing L, Juul N, Drud N, Boomsma TK (2017) A real options approach to analyse wind energy investments under different support schemes. Appl Energy 188:83–96. https://doi.org/10.1016/j.apenergy.2016.11.104

Kim KT, Lee DJ, Park SJ (2014) Evaluation of R&D investments in wind power in Korea using real option. Renew Sust Energ Rev 40:335–347. https://doi.org/10.1016/j.rser.2014.07.165

Lee H, Park T, Kim B, Kim K, Kim H (2013) A real option-based model for promoting sustainable energy projects under the clean development mechanism. Energy Policy 54:360–368. https://doi.org/10.1016/j.rser.2014.07.165

Tian et al. (2017). The valuation of photovoltaic power generation under carbon market linkage based on real options. Appl Energy, 201:354-362. doi: https://doi.org/10.1016/j.apenergy.2016.12.092

Myers SC (1977) The determinants of corporate borrowing. J Financ Econ 5:147–175. https://doi.org/10.1016/0304-405X(77)90015-0

Copeland T, Antikarov V (2003) Real options: a practitioner’s guide. Cen gage Learning, New York

Baecker PN (2007) Real options and intellectual property: capital budgeting under imperfect patent protection. Springer Berlin Heidelberg

Bertsekas DP (2012) Dynamic programming and optimal control, Vol. 2, fourth ed. Athena Scientific.

Dixit AK, Pindyck RS (1994) Investment under uncertainty. Princeton University Press, New Jersey

Fonseca MN et al (2017) Oil price volatility: a real option valuation approach in an African oil field. J Pet Sci Eng 150:297–304. https://doi.org/10.1016/j.petrol.2016.12.024

Guedes J, Santos P (2016) Valuing an offshore oil exploration and production project through real options analysis. Energy Econ 60:377–386. https://doi.org/10.1016/j.eneco.2016.09.024

Postali FAS, Picchetti P (2006) Geometric Brownian motion and structural breaks in oil prices: a quantitative analysis. Energy Econ 28(4):506–522. https://doi.org/10.1016/j.eneco.2006.02.011

Insley M (2002) A real options approach to the valuation of a forestry investment. J Environ Econ Manag 44(3):471–492. https://doi.org/10.1006/jeem.2001.1209

Article   MATH   Google Scholar  

Davis GA, Cairns RD (2012) Good timing: the economics of optimal stopping. J Econ Dyn Control 36(2):255–265. https://doi.org/10.1016/j.jedc.2011.09.008 .

DOE (2016) Awarded Solar Grid 2016. Philippines’ Department of Energy https://www.doe.gov.ph/sites/default/files/pdf/renewable_energy/awarded_solar_grid_20160630.pdf Accessed: 16 Jan 2017

Paleco (2016) Status of electrification. Palawan Electric Cooperative Accessed: 16 Jan 2017

EEA (2010). Estimated average EU external costs for electricity generation technologies in 2005. European Environmental Agency. http://www.eea.europa.eu/data-and-maps/figures/estimated-average-eu-external-costs Accessed 20 March 2017

Abadie LM, Chamorro JM (2014) Valuation of wind energy projects: a real options approach. Energies 7:3218–3255. https://doi.org/10.3390/en7053218

Jeon C, Lee J, Shin J (2015) Optimal subsidy estimation method using system dynamics and the real option model: photovoltaic technology case. Appl Energy 142:33–43. https://doi.org/10.1016/j.apenergy.2014.12.067

Barrera GM, Ramírez CZ, González JMG (2016) Application of real options valuation for analysing the impact of public R&D financing on renewable energy projects: a company’s perspective. Renew Sust Energ Rev 63:292–301. https://doi.org/10.1016/j.rser.2016.05.073

Eryilmaz D, Homans R (2016) How does uncertainty in renewable energy policy affect decisions to invest in wind energy? Electr J 29(3):64–71. https://doi.org/10.1016/j.tej.2015.12.002

Ritzenhofen I, Spinler S (2016) Optimal design of feed-in-tariffs to stimulate renewable energy investments under regulatory uncertainty—a real options analysis. Energy Econ 53:76–89. https://doi.org/10.1016/j.eneco.2014.12.008

Download references

Acknowledgements

We acknowledge the support by the DFG Open Access Publication Funds of the Ruhr-Universität Bochum.

Author information

Authors and affiliations.

Institute of Development Research and Development Policy, Ruhr University of Bochum, Universitaetsstr. 105, 44789, Bochum, Germany

Casper Boongaling Agaton

Faculty of Management and Economics, Ruhr University of Bochum, Universitaetsstr. 150, 44801, Bochum, Germany

Helmut Karl

You can also search for this author in PubMed   Google Scholar

Contributions

CA conceptualized the research objectives and modeling scenarios. All authors contributed to the data analysis and writing of the final manuscript. All authors read and approved the manuscript.

Corresponding author

Correspondence to Casper Boongaling Agaton .

Ethics declarations

Competing interests.

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Additional file

Additional file 1:.

Table S1. ADF unit root test result of oil prices from 1981-2016. Table S2. Note: elec+2_0: option values at 25% higher electricity price than the base at the initial period; elec+2_T: option values at 25% higher electricity price than the base at the terminal period elec+1_0: option values at 10% higher electricity price than the base at the initial period; elec+1_T: option values at 10% higher electricity price than the base at the terminal period; base_0: option values of energy investment at the initial period; base_T: option values of energy investment at the terminal period; elec-1_0: option values at 10% lower electricity price than the base at the initial period; elec-1_T: option values at 10% lower electricity price than the base at the terminal period; elec-2_0: option values at 25% lower electricity price than the base at the initial period; elec-2_T: option values at 25% lower electricity price than the base at the terminal period; elec-3_0: option values at 40% lower electricity price than the base at the initial period; elec-3_T: option values at 40% lower electricity price than the base at the terminal period. Table S3. base_0: option values of energy investment with no externality at the initial period; base_T: option values of energy investment with no externality at the terminal period; ex1_0: option values at 20/ MWhexternalitycosttheinitialperiod; ex 1 T : optionvaluesat20/MWh externality cost at the terminal period; ex2_0: option values at 40/ MWhexternalitycosttheinitialperiod; ex 2 T : optionvaluesat40/MWh externality cost at the terminal period; ex3_0: option values at 60/ MWhexternalitycosttheinitialperiod;ex 3 T : optionvaluesat60/MWh externality cost at the terminal period; ex3_0: option values at 80/ MWhexternalitycosttheinitialperiod; ex 4 T : optionvaluesat80/MWh externality cost at the terminal period. (DOCX 95 kb)

Rights and permissions

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/ ), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Reprints and permissions

About this article

Cite this article.

Agaton, C.B., Karl, H. A real options approach to renewable electricity generation in the Philippines. Energ Sustain Soc 8 , 1 (2018). https://doi.org/10.1186/s13705-017-0143-y

Download citation

Received : 26 June 2017

Accepted : 14 December 2017

Published : 09 January 2018

DOI : https://doi.org/10.1186/s13705-017-0143-y

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Price uncertainty
• Externality tax

Energy, Sustainability and Society

ISSN: 2192-0567

• General enquiries: [email protected]

Create an account

Create a free IEA account to download our reports or subcribe to a paid service.

Net Zero by 2050

A Roadmap for the Global Energy Sector

This report is part of Net Zero Emissions

About this report

The number of countries announcing pledges to achieve net zero emissions over the coming decades continues to grow. But the pledges by governments to date – even if fully achieved – fall well short of what is required to bring global energy-related carbon dioxide emissions to net zero by 2050 and give the world an even chance of limiting the global temperature rise to 1.5 °C. This special report is the world’s first comprehensive study of how to transition to a net zero energy system by 2050 while ensuring stable and affordable energy supplies, providing universal energy access, and enabling robust economic growth. It sets out a cost-effective and economically productive pathway, resulting in a clean, dynamic and resilient energy economy dominated by renewables like solar and wind instead of fossil fuels. The report also examines key uncertainties, such as the roles of bioenergy, carbon capture and behavioural changes in reaching net zero.

Summary for policy makers

Reaching net zero emissions globally by 2050 is a critical and formidable goal.

The energy sector is the source of around three-quarters of greenhouse gas emissions today and holds the key to averting the worst effects of climate change, perhaps the greatest challenge humankind has faced. Reducing global carbon dioxide (CO 2 ) emissions to net zero by 2050 is consistent with efforts to limit the long-term increase in average global temperatures to 1.5˚C. This calls for nothing less than a complete transformation of how we produce, transport and consume energy. The growing political consensus on reaching net zero is cause for considerable optimism about the progress the world can make, but the changes required to reach net zero emissions globally by 2050 are poorly understood. A huge amount of work is needed to turn today’s impressive ambitions into reality, especially given the range of different situations among countries and their differing capacities to make the necessary changes. This special IEA report sets out a pathway for achieving this goal, resulting in a clean and resilient energy system that would bring major benefits for human prosperity and well-being.

The global pathway to net zero emissions by 2050 detailed in this report requires all governments to significantly strengthen and then successfully implement their energy and climate policies. Commitments made to date fall far short of what is required by that pathway. The number of countries that have pledged to achieve net zero emissions has grown rapidly over the last year and now covers around 70% of global emissions of CO 2 . This is a huge step forward. However, most pledges are not yet underpinned by near-term policies and measures. Moreover, even if successfully fulfilled, the pledges to date would still leave around 22 billion tonnes of CO 2 emissions worldwide in 2050. The continuation of that trend would be consistent with a temperature rise in 2100 of around 2.1 °C. Global emissions fell in 2020 because of the Covid-19 crisis but are already rebounding strongly as economies recover. Further delay in acting to reverse that trend will put net zero by 2050 out of reach.

In this Summary for Policy Makers, we outline the essential conditions for the global energy sector to reach net zero CO 2 emissions by 2050. The pathway described in depth in this report achieves this objective with no offsets from outside the energy sector, and with low reliance on negative emissions technologies. It is designed to maximise technical feasibility, cost-effectiveness and social acceptance while ensuring continued economic growth and secure energy supplies. We highlight the priority actions that are needed today to ensure the opportunity of net zero by 2050 – narrow but still achievable – is not lost. The report provides a global view, but countries do not start in the same place or finish at the same time: advanced economies have to reach net zero before emerging markets and developing economies, and assist others in getting there. We also recognise that the route mapped out here is a path, not necessarily the path, and so we examine some key uncertainties, notably concerning the roles played by bioenergy, carbon capture and behavioural changes. Getting to net zero will involve countless decisions by people across the world, but our primary aim is to inform the decisions made by policy makers, who have the greatest scope to move the world closer to its climate goals.

Net zero by 2050 hinges on an unprecedented clean technology push to 2030

The path to net zero emissions is narrow: staying on it requires immediate and massive deployment of all available clean and efficient energy technologies. In the net zero emissions pathway presented in this report, the world economy in 2030 is some 40% larger than today but uses 7% less energy. A major worldwide push to increase energy efficiency is an essential part of these efforts, resulting in the annual rate of energy intensity improvements averaging 4% to 2030 – about three-times the average rate achieved over the last two decades. Emissions reductions from the energy sector are not limited to CO 2 : in our pathway, methane emissions from fossil fuel supply fall by 75% over the next ten years as a result of a global, concerted effort to deploy all available abatement measures and technologies.

Ever-cheaper renewable energy technologies give electricity the edge in the race to zero. Our pathway calls for scaling up solar and wind rapidly this decade, reaching annual additions of 630 gigawatts (GW) of solar photovoltaics (PV) and 390 GW of wind by 2030, four-times the record levels set in 2020. For solar PV, this is equivalent to installing the world’s current largest solar park roughly every day. Hydropower and nuclear, the two largest sources of low-carbon electricity today, provide an essential foundation for transitions. As the electricity sector becomes cleaner, electrification emerges as a crucial economy-wide tool for reducing emissions. Electric vehicles (EVs) go from around 5% of global car sales to more than 60% by 2030.  

Priority action: Make the 2020s the decade of massive clean energy expansion

All the technologies needed to achieve the necessary deep cuts in global emissions by 2030 already exist, and the policies that can drive their deployment are already proven.

As the world continues to grapple with the impacts of the Covid-19 pandemic, it is essential that the resulting wave of investment and spending to support economic recovery is aligned with the net zero pathway. Policies should be strengthened to speed the deployment of clean and efficient energy technologies. Mandates and standards are vital to drive consumer spending and industry investment into the most efficient technologies. Targets and competitive auctions can enable wind and solar to accelerate the electricity sector transition. Fossil fuel subsidy phase-outs, carbon pricing and other market reforms can ensure appropriate price signals. Policies should limit or provide disincentives for the use of certain fuels and technologies, such as unabated coal-fired power stations, gas boilers and conventional internal combustion engine vehicles. Governments must lead the planning and incentivising of the massive infrastructure investment, including in smart transmission and distribution grids.

Electric car sales in the net zero pathway, 2020-2030

Capacity additions of solar pv and wind in the net zero pathway, 2020-2030, energy intensity of gdp in the net zero pathway, 2020-2030, net zero by 2050 requires huge leaps in clean energy innovation.

Reaching net zero by 2050 requires further rapid deployment of available technologies as well as widespread use of technologies that are not on the market yet. Major innovation efforts must occur over this decade in order to bring these new technologies to market in time. Most of the global reductions in CO 2 emissions through 2030 in our pathway come from technologies readily available today. But in 2050, almost half the reductions come from technologies that are currently at the demonstration or prototype phase. In heavy industry and long-distance transport, the share of emissions reductions from technologies that are still under development today is even higher.

The biggest innovation opportunities concern advanced batteries, hydrogen electrolysers, and direct air capture and storage. Together, these three technology areas make vital contributions the reductions in CO 2 emissions between 2030 and 2050 in our pathway. Innovation over the next ten years – not only through research and development (R&D) and demonstration but also through deployment – needs to be accompanied by the large-scale construction of the infrastructure the technologies will need. This includes new pipelines to transport captured CO 2 emissions and systems to move hydrogen around and between ports and industrial zones.

Priority action: Prepare for the next phase of the transition by boosting innovation

Clean energy innovation must accelerate rapidly, with governments putting R&D, demonstration and deployment at the core of energy and climate policy.

Government R&D spending needs to be increased and reprioritised. Critical areas such as electrification, hydrogen, bioenergy and carbon capture, utilisation and storage (CCUS) today receive only around one-third of the level of public R&D funding of the more established low-carbon electricity generation and energy efficiency technologies. Support is also needed to accelerate the roll-out of demonstration projects, to leverage private investment in R&D, and to boost overall deployment levels to help reduce costs. Around USD 90 billion of public money needs to be mobilised globally as soon as possible to complete a portfolio of demonstration projects before 2030. Currently, only roughly USD 25 billion is budgeted for that period. Developing and deploying these technologies would create major new industries, as well as commercial and employment opportunities.

Annual CO2 emissions savings in the net zero pathway, 2030 and 2050, relative to 2020

The transition to net zero is for and about people.

A transition of the scale and speed described by the net zero pathway cannot be achieved without sustained support and participation from citizens. The changes will affect multiple aspects of people’s lives – from transport, heating and cooking to urban planning and jobs. We estimate that around 55% of the cumulative emissions reductions in the pathway are linked to consumer choices such as purchasing an EV, retrofitting a house with energy-efficient technologies or installing a heat pump. Behavioural changes, particularly in advanced economies – such as replacing car trips with walking, cycling or public transport, or foregoing a long-haul flight – also provide around 4% of the cumulative emissions reductions.

Providing electricity to around 785 million people that have no access and clean cooking solutions to 2.6 billion people that lack those options is an integral part of our pathway. Emissions reductions have to go hand-in-hand with efforts to ensure energy access for all by 2030. This costs around USD 40 billion a year, equal to around 1% of average annual energy sector investment, while also bringing major co-benefits from reduced indoor air pollution.

Some of the changes brought by the clean energy transformation may be challenging to implement, so decisions must be transparent, just and cost-effective. Governments need to ensure that clean energy transitions are people-centred and inclusive. Household energy expenditure as a share of disposable income – including purchases of efficient appliances and fuel bills – rises modestly in emerging market and developing economies in our net zero pathway as more people gain access to energy and demand for modern energy services increases rapidly. Ensuring the affordability of energy for households demands close attention: policy tools that can direct support to the poorest include tax credits, loans and targeted subsidies.

Priority action: Clean energy jobs will grow strongly but must be spread widely

Energy transitions have to take account of the social and economic impacts on individuals and communities, and treat people as active participants.

The transition to net zero brings substantial new opportunities for employment, with 14 million jobs created by 2030 in our pathway thanks to new activities and investment in clean energy. Spending on more efficient appliances, electric and fuel cell vehicles, and building retrofits and energy-efficient construction would require a further 16 million workers. But these opportunities are often in different locations, skill sets and sectors than the jobs that will be lost as fossil fuels decline. In our pathway, around 5 million jobs are lost. Most of those jobs are located close to fossil fuel resources, and many are well paid, meaning structural changes can cause shocks for communities with impacts that persist over time. This requires careful policy attention to address the employment losses. It will be vital to minimise hardships associated with these disruptions, such as by retraining workers, locating new clean energy facilities in heavily affected areas wherever possible, and providing regional aid.

Global employment in energy supply in the Net Zero Scenario, 2019-2030

An energy sector dominated by renewables.

In the net zero pathway, global energy demand in 2050 is around 8% smaller than today, but it serves an economy more than twice as big and a population with 2 billion more people. More efficient use of energy, resource efficiency and behavioural changes combine to offset increases in demand for energy services as the world economy grows and access to energy is extended to all.

Instead of fossil fuels, the energy sector is based largely on renewable energy. Two-thirds of total energy supply in 2050 is from wind, solar, bioenergy, geothermal and hydro energy. Solar becomes the largest source, accounting for one-fifth of energy supplies. Solar PV capacity increases 20-fold between now and 2050, and wind power 11-fold.

Net zero means a huge decline in the use of fossil fuels. They fall from almost four-fifths of total energy supply today to slightly over one-fifth by 2050. Fossil fuels that remain in 2050 are used in goods where the carbon is embodied in the product such as plastics, in facilities fitted with CCUS, and in sectors where low-emissions technology options are scarce.

Electricity accounts for almost 50% of total energy consumption in 2050. It plays a key role across all sectors – from transport and buildings to industry – and is essential to produce low-emissions fuels such as hydrogen. To achieve this, total electricity generation increases over two-and-a-half-times between today and 2050. At the same time, no additional new final investment decisions should be taken for new unabated coal plants, the least efficient coal plants are phased out by 2030, and the remaining coal plants still in use by 2040 are retrofitted. By 2050, almost 90% of electricity generation comes from renewable sources, with wind and solar PV together accounting for nearly 70%. Most of the remainder comes from nuclear.    

Emissions from industry, transport and buildings take longer to reduce. Cutting industry emissions by 95% by 2050 involves major efforts to build new infrastructure. After rapid innovation progress through R&D, demonstration and initial deployment between now and 2030 to bring new clean technologies to market, the world then has to put them into action. Every month from 2030 onwards, ten heavy industrial plants are equipped with CCUS, three new hydrogen-based industrial plants are built, and 2 GW of electrolyser capacity are added at industrial sites. Policies that end sales of new internal combustion engine cars by 2035 and boost electrification underpin the massive reduction in transport emissions. In 2050, cars on the road worldwide run on electricity or fuel cells. Low-emissions fuels are essential where energy needs cannot easily or economically be met by electricity. For example, aviation relies largely on biofuels and synthetic fuels, and ammonia is vital for shipping. In buildings, bans on new fossil fuel boilers need to start being introduced globally in 2025, driving up sales of electric heat pumps. Most old buildings and all new ones comply with zero-carbon-ready building energy codes. 1

Priority action: Set near-term milestones to get on track for long-term targets

Governments need to provide credible step-by-step plans to reach their net zero goals, building confidence among investors, industry, citizens and other countries.

Governments must put in place long-term policy frameworks to allow all branches of government and stakeholders to plan for change and facilitate an orderly transition. Long-term national low-emissions strategies, called for by the Paris Agreement, can set out a vision for national transitions, as this report has done on a global level. These long-term objectives need to be linked to measurable short-term targets and policies. Our pathway details more than 400 sectoral and technology milestones to guide the global journey to net zero by 2050.  

There is no need for investment in new fossil fuel supply in our net zero pathway

Beyond projects already committed as of 2021, there are no new oil and gas fields approved for development in our pathway, and no new coal mines or mine extensions are required. The unwavering policy focus on climate change in the net zero pathway results in a sharp decline in fossil fuel demand, meaning that the focus for oil and gas producers switches entirely to output – and emissions reductions – from the operation of existing assets. Unabated coal demand declines by 98% to just less than 1% of total energy use in 2050. Gas demand declines by 55% to 1 750 billion cubic metres and oil declines by 75% to 24 million barrels per day (mb/d), from around 90 mb/d in 2020.

Clean electricity generation, network infrastructure and end-use sectors are key areas for increased investment. Enabling infrastructure and technologies are vital for transforming the energy system. Annual investment in transmission and distribution grids expands from USD 260 billion today to USD 820 billion in 2030. The number of public charging points for EVs rises from around 1 million today to 40 million in 2030, requiring annual investment of almost USD 90 billion in 2030. Annual battery production for EVs leaps from 160 gigawatt-hours (GWh) today to 6 600 GWh in 2030 – the equivalent of adding almost 20 gigafactories 2  each year for the next ten years. And the required roll-out of hydrogen and CCUS after 2030 means laying the groundwork now: annual investment in CO 2 pipelines and hydrogen-enabling infrastructure increases from USD 1 billion today to around USD 40 billion in 2030.

Priority action: Drive a historic surge in clean energy investment

Policies need to be designed to send market signals that unlock new business models and mobilise private spending, especially in emerging economies.

Accelerated delivery of international public finance will be critical to energy transitions, especially in developing economies, but ultimately the private sector will need to finance most of the extra investment required. Mobilising the capital for large-scale infrastructure calls for closer co operation between developers, investors, public financial institutions and governments. Reducing risks for investors will be essential to ensure successful and affordable clean energy transitions. Many emerging market and developing economies, which rely mainly on public funding for new energy projects and industrial facilities, will need to reform their policy and regulatory frameworks to attract more private finance. International flows of long-term capital to these economies will be needed to support the development of both existing and emerging clean energy technologies.

Clean energy investment in the net zero pathway, 2016-2050

An unparalleled clean energy investment boom lifts global economic growth.

Total annual energy investment surges to USD 5 trillion by 2030, adding an extra 0.4 percentage point a year to annual global GDP growth, based on our joint analysis with the International Monetary Fund. This unparalleled increase – with investment in clean energy and energy infrastructure more than tripling already by 2030 – brings significant economic benefits as the world emerges from the Covid-19 crisis. The jump in private and government spending creates millions of jobs in clean energy, including energy efficiency, as well as in the engineering, manufacturing and construction industries. All of this puts global GDP 4% higher in 2030 than it would be based on current trends.

Governments have a key role in enabling investment-led growth and ensuring that the benefits are shared by all. There are large differences in macroeconomic impacts between regions. But government investment and public policies are essential to attract large amounts of private capital and to help offset the declines in fossil fuel income that many countries will experience. The major innovation efforts needed to bring new clean energy technologies to market could boost productivity and create entirely new industries, providing opportunities to locate them in areas that see job losses in incumbent industries. Improvements in air quality provide major health benefits, with 2 million fewer premature deaths globally from air pollution in 2030 than today in our net zero pathway. Achieving universal energy access by 2030 would provide a major boost to well-being and productivity in developing economies.

New energy security concerns emerge, and old ones remain

The contraction of oil and natural gas production will have far-reaching implications for all the countries and companies that produce these fuels. No new oil and natural gas fields are needed in our pathway, and oil and natural gas supplies become increasingly concentrated in a small number of low-cost producers. For oil, the OPEC share of a much-reduced global oil supply increases from around 37% in recent years to 52% in 2050, a level higher than at any point in the history of oil markets. Yet annual per capita income from oil and natural gas in producer economies falls by about 75%, from USD 1 800 in recent years to USD 450 by the 2030s, which could have knock-on societal effects. Structural reforms and new sources of revenue are needed, even though these are unlikely to compensate fully for the drop in oil and gas income. While traditional supply activities decline, the expertise of the oil and natural gas industry fits well with technologies such as hydrogen, CCUS and offshore wind that are needed to tackle emissions in sectors where reductions are likely to be most challenging.

The energy transition requires substantial quantities of critical minerals, and their supply emerges as a significant growth area. The total market size of critical minerals like copper, cobalt, manganese and various rare earth metals grows almost sevenfold between 2020 and 2030 in the net zero pathway. Revenues from those minerals are larger than revenues from coal well before 2030. This creates substantial new opportunities for mining companies. It also creates new energy security concerns, including price volatility and additional costs for transitions, if supply cannot keep up with burgeoning demand.

The rapid electrification of all sectors makes electricity even more central to energy security around the world than it is today. Electricity system flexibility – needed to balance wind and solar with evolving demand patterns – quadruples by 2050 even as retirements of fossil fuel capacity reduce conventional sources of flexibility. The transition calls for major increases in all sources of flexibility: batteries, demand response and low-carbon flexible power plants, supported by smarter and more digital electricity networks. The resilience of electricity systems to cyberattacks and other emerging threats needs to be enhanced.

Priority action: Address emerging energy security risks now

Ensuring uninterrupted and reliable supplies of energy and critical energy-related commodities at affordable prices will only rise in importance on the way to net zero.

The focus of energy security will evolve as reliance on renewable electricity grows and the role of oil and gas diminishes. Potential vulnerabilities from the increasing importance of electricity include the variability of supply and cybersecurity risks. Governments need to create markets for investment in batteries, digital solutions and electricity grids that reward flexibility and enable adequate and reliable supplies of electricity. The growing dependence on critical minerals required for key clean energy technologies calls for new international mechanisms to ensure both the timely availability of supplies and sustainable production. At the same time, traditional energy security concerns will not disappear, as oil production will become more concentrated.

Critical minerals demand in the net zero pathway, 2020-2050

Oil supply in the net zero pathway, 2020-2050, international co-operation is pivotal for achieving net zero emissions by 2050.

Making net zero emissions a reality hinges on a singular, unwavering focus from all governments – working together with one another, and with businesses, investors and citizens. All stakeholders need to play their part. The wide-ranging measures adopted by governments at all levels in the net zero pathway help to frame, influence and incentivise the purchase by consumers and investment by businesses. This includes how energy companies invest in new ways of producing and supplying energy services, how businesses invest in equipment, and how consumers cool and heat their homes, power their devices and travel.

Underpinning all these changes are policy decisions made by governments. Devising cost-effective national and regional net zero roadmaps demands co-operation among all parts of government that breaks down silos and integrates energy into every country’s policy making on finance, labour, taxation, transport and industry. Energy or environment ministries alone cannot carry out the policy actions needed to reach net zero by 2050.

Changes in energy consumption result in a significant decline in fossil fuel tax revenues. In many countries today, taxes on diesel, gasoline and other fossil fuel consumption are an important source of public revenues, providing as much as 10% in some cases. In the net zero pathway, tax revenue from oil and gas retail sales falls by about 40% between 2020 and 2030. Managing this decline will require long-term fiscal planning and budget reforms.

The net zero pathway relies on unprecedented international co-operation among governments, especially on innovation and investment. The IEA stands ready to support governments in preparing national and regional net zero roadmaps, to provide guidance and assistance in implementing them, and to promote international co-operation to accelerate the energy transition worldwide. 

Priority action: Take international co-operation to new heights

This is not simply a matter of all governments seeking to bring their national emissions to net zero – it means tackling global challenges through co-ordinated actions.

Governments must work together in an effective and mutually beneficial manner to implement coherent measures that cross borders. This includes carefully managing domestic job creation and local commercial advantages with the collective global need for clean energy technology deployment. Accelerating innovation, developing international standards and co-ordinating to scale up clean technologies needs to be done in a way that links national markets. Co-operation must recognise differences in the stages of development of different countries and the varying situations of different parts of society. For many rich countries, achieving net zero emissions will be more difficult and costly without international co-operation. For many developing countries, the pathway to net zero without international assistance is not clear. Technical and financial support is needed to ensure deployment of key technologies and infrastructure. Without greater international co-operation, global CO 2 emissions will not fall to net zero by 2050. 

Global energy-related CO2 emissions in the net zero pathway and Low International Cooperation Case, 2010-2090

A zero-carbon-ready building is highly energy efficient and either uses renewable energy directly or uses an energy supply that will be fully decarbonised by 2050, such as electricity or district heat.

Battery gigafactory capacity assumption = 35 gigawatt-hours per year.

Reference 1

Reference 2, related net zero reports.

Related files

Executive summaries.

• English Download "English"
• Italian Download "Italian"

Full report translations

• Chinese Download "Chinese"
• Polish Download "Polish"

Additional downloads

• Launch presentation Download "Launch presentation"
• The need for net zero demonstration projects Download "The need for net zero demonstration projects"

Cite report

IEA (2021), Net Zero by 2050 , IEA, Paris https://www.iea.org/reports/net-zero-by-2050, Licence: CC BY 4.0

Share this report

• Share on Twitter Twitter
• Share on Facebook Facebook
• Share on LinkedIn LinkedIn
• Share on Email Email
• Share on Print Print

Subscription successful

Thank you for subscribing. You can unsubscribe at any time by clicking the link at the bottom of any IEA newsletter.

Information

• Author Services

Initiatives

You are accessing a machine-readable page. In order to be human-readable, please install an RSS reader.

All articles published by MDPI are made immediately available worldwide under an open access license. No special permission is required to reuse all or part of the article published by MDPI, including figures and tables. For articles published under an open access Creative Common CC BY license, any part of the article may be reused without permission provided that the original article is clearly cited. For more information, please refer to https://www.mdpi.com/openaccess .

Feature papers represent the most advanced research with significant potential for high impact in the field. A Feature Paper should be a substantial original Article that involves several techniques or approaches, provides an outlook for future research directions and describes possible research applications.

Feature papers are submitted upon individual invitation or recommendation by the scientific editors and must receive positive feedback from the reviewers.

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

Original Submission Date Received: .

• Active Journals
• Find a Journal
• Proceedings Series
• For Authors
• For Reviewers
• For Editors
• For Librarians
• For Publishers
• For Societies
• For Conference Organizers
• Open Access Policy
• Institutional Open Access Program
• Special Issues Guidelines
• Editorial Process
• Research and Publication Ethics
• Article Processing Charges
• Testimonials
• Preprints.org
• SciProfiles
• Encyclopedia

Article Menu

• Subscribe SciFeed
• Recommended Articles
• Google Scholar
• on Google Scholar
• Table of Contents

Find support for a specific problem in the support section of our website.

Please let us know what you think of our products and services.

Visit our dedicated information section to learn more about MDPI.

JSmol Viewer

Alternative heating, ventilation, and air conditioning (hvac) system considerations for reducing energy use and emissions in egg industries in temperate and continental climates: a systematic review of current systems, insights, and future directions.

1. Introduction

• What are the typical annual energy needs and the maximum thermal loads for heating and cooling caged and free-run layer hen housing systems? This research question considers the specific physiological requirements of poultry, housing characteristics, and seasonal variations across temperate and continental climates (using several locations in Canada evincing different temperate/continental climate conditions as examples) throughout the year (RQ1).
• What insights from residential and commercial alternative HVAC systems are transferable for potential application in caged and free-run poultry housing systems in temperate and continental climates? What are the limitations? This research question considers the estimated heating and cooling loads and needs from RQ1, potential energy efficiency, and environmental impacts (RQ2).
• What subset of alternative HVAC technologies could be recommended for priority consideration for application in confined poultry housing, subject to further, detailed life cycle-based sustainability assessment in order to determine potential net benefits/impacts in the context of egg production? This research question considers technological maturity, affordability, and the findings from RQ2 (RQ3).

2.1. Simulation Methodology

2.1.1. adopted simulation model, 2.1.2. theoretical layer hen house used in the simulations, 2.1.3. definition of the scenarios for the simulations, 2.2. prisma methodology, 2.2.1. search strategy and screening criteria, 2.2.2. extraction and synthesis of data, 3. results and discussion, 3.1. thermal loads and needs for conventional caged and free-run layer hen housing, 3.2. insights into the suitability of alternative hvac systems, 3.2.1. ashps for caged and free-run poultry housing applications.

3.2.2. EAHEs for Caged and Free-Run Poultry Housing Applications in Different Temperate and Continental Climates

3.2.3. GSHPs for Caged and Free-Run Poultry Housing Applications in Different Temperate and Continental Climates

3.3. affordability analysis for the application of alternative hvac systems in egg production systems, 3.3.1. technological maturity of alternative hvac systems, 3.3.2. recommendations of alternative hvac systems based on the synthesis of affordability, technological maturity, and results from rq2, 4. conclusions, future directions, and limitations.

• EAHEs are the alternative HVAC technology of highest priority for future investigation as a complementary system to reduce thermal loads and needs in poultry housing. Due to their passive nature, EAHEs were determined to have the smallest costs and potential environmental impacts. Combining EAHEs with conventional systems as a potentially economical and environmentally beneficial alternative to switching from conventional to active alternative HVAC systems would be worth future exploration, particularly for low-thermal-load and -energy-needs houses such as in mild temperate climates and free-run systems.
• GSHPs are of second priority for further investigation as stand-alone systems. Despite their high installation costs, GSHPs were determined to possibly be energy-efficient and environmentally beneficial for egg production compared to other active systems due to having low operational costs. Although GSHPs would benefit both poultry housing systems, they would be particularly advantageous for caged systems due to the high thermal load and associated operational demand. Possible future work on reducing investment costs for GSHPs would be beneficial.
• ASHPs are not recommended as a priority alternative HVAC system. Despite favourable literature findings as an affordable, energy-efficient system, many environmental impact findings were unfavourable. There is no strong indication from the literature that ASHPs would be superior in terms of environmental sustainability to conventional or GSHP systems. It is worth noting that the installation of ASHPs is usually easier. Nevertheless, further environmental impact investigation is suggested before large-scale implementations of ASHPs in livestock contexts, particularly for high-thermal-load and -energy-needs applications.
• GSAHPs and WSHPs are not recommended for priority consideration at this time. WSHPs are technologically mature but, as the literature is limited, these systems’ suitability for egg production could not be determined. Moreover, as WSHPs need access to large bodies of water, their implementation can be geographically limited. GSAHPs are not technologically mature, and the limited literature also prevents the determination of these systems’ suitability. We encourage further research on WSHPs and GSAHPs as these systems are theoretically promising but require more investigation of their potential energy efficiencies, environmental impacts, and affordability to better understand their suitability across different application contexts.

Supplementary Materials

Author contributions, institutional review board statement, informed consent statement, data availability statement, conflicts of interest, abbreviations.

• UN. Day of 8 Billion. Available online: https://www.un.org/en/dayof8billion (accessed on 9 February 2023).
• FAO. The Future of Food and Agriculture–Trends and Challenges ; FAO: Rome, Italy, 2017; Volume 4. [ Google Scholar ]
• Pelletier, N.; Tyedmers, P. Forecasting potential global environmental costs of livestock production 2000–2050. Proc. Natl. Acad. Sci. USA 2010 , 107 , 18371–18374. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Slater, J.; Yeudall, F. Sustainable Livelihoods for Food and Nutrition Security in Canada: A Conceptual Framework for Public Health Research, Policy, and Practice. J. Hunger Environ. Nutr. 2015 , 10 , 1–21. [ Google Scholar ] [ CrossRef ]
• Marques, G.M.; Teixeira, C.M.G.L.; Sousa, T.; Morais, T.G.; Teixeira, R.F.M.; Domingos, T. Minimizing direct greenhouse gas emissions in livestock production: The need for a metabolic theory. Ecol. Model. 2020 , 434 , 109259. [ Google Scholar ] [ CrossRef ]
• Steinfeld, H.; Gerber, P.; Wassenaar, T.; Castel, V.; Rosales, M.; de Haan, C. Livestock’s Long Shadow: Environmental Issues and Options ; FAO/LEAD; Food and Agriculture Organization of the United Nations: Rome, Italy, 2006. [ Google Scholar ]
• Goodland, R.; Anhang, J. Livestock and Climate Change: What if the Key Actors in Climate Change are... Cows, Pigs, and Chickens? Worldwatch Institute: Washington, DC, USA, 2009. [ Google Scholar ]
• Laca, A.; Laca, A.; Diaz, M. Chapter 4–Environmental impact of poultry farming and egg production. In Environmental Impact of Agro-Food Industry and Food Consumption ; Galanakis, C.M., Ed.; Academic Press: New York, NY, USA, 2021; pp. 81–100. ISBN 978-0-12-821363-6. [ Google Scholar ]
• Alexandratos, N.; Bruinsma, J. World Agriculture Towards 2030/2050: The 2012 Revision ; FAO: Rome, Italy, 2012. [ Google Scholar ]
• Kanani, F.; Heidari, M.D.; Gilroyed, B.H.; Pelletier, N. Waste valorization technology options for the egg and broiler industries: A review and recommendations. J. Clean. Prod. 2020 , 262 , 121129. [ Google Scholar ] [ CrossRef ]
• Ershadi, S.Z.; Dias, G.; Heidari, M.D.; Pelletier, N. Improving nitrogen use efficiency in crop-livestock systems: A review of mitigation technologies and management strategies, and their potential applicability for egg supply chains. J. Clean. Prod. 2020 , 265 , 121671. [ Google Scholar ] [ CrossRef ]
• Li, Y.; Arulnathan, V.; Heidari, M.D.; Pelletier, N. Design considerations for net zero energy buildings for intensive, confined poultry production: A review of current insights, knowledge gaps, and future directions. Renew. Sustain. Energy Rev. 2022 , 154 , 111874. [ Google Scholar ] [ CrossRef ]
• Bengtsson, J.; Seddon, J. Cradle to retailer or quick service restaurant gate life cycle assessment of chicken products in Australia. J. Clean. Prod. 2013 , 41 , 291–300. [ Google Scholar ] [ CrossRef ]
• Costantino, A.; Fabrizio, E.; Biglia, A.; Cornale, P.; Battaglini, L. Energy Use for Climate Control of Animal Houses: The State of the Art in Europe. Energy Procedia 2016 , 101 , 184–191. [ Google Scholar ] [ CrossRef ]
• Baxevanou, C.; Fidaros, D.; Bartzanas, T.; Kittas, C. Energy Consumption and Energy Saving Measures in Poultry. Energy Environ. Eng. 2017 , 5 , 29–36. [ Google Scholar ] [ CrossRef ]
• Grassauer, F.; Arulnathan, V.; Pelletier, N. Towards a net-zero greenhouse gas emission egg industry: A review of relevant mitigation technologies and strategies, current emission reduction potential, and future research needs. Renew. Sustain. Energy Rev. 2023 , 181 , 113322. [ Google Scholar ] [ CrossRef ]
• Self, S.J.; Reddy, B.V.; Rosen, M.A. Geothermal heat pump systems: Status review and comparison with other heating options. Appl. Energy 2013 , 101 , 341–348. [ Google Scholar ] [ CrossRef ]
• Sarbu, I.; Sebarchievici, C. General review of ground-source heat pump systems for heating and cooling of buildings. Energy Build. 2014 , 70 , 441–454. [ Google Scholar ] [ CrossRef ]
• Bisoniya, T.S.; Kumar, A.; Baredar, P. Experimental and analytical studies of earth–air heat exchanger (EAHE) systems in India: A review. Renew. Sustain. Energy Rev. 2013 , 19 , 238–246. [ Google Scholar ] [ CrossRef ]
• Mattinen, M.K.; Nissinen, A.; Hyysalo, S.; Juntunen, J.K. Energy Use and Greenhouse Gas Emissions of Air-Source Heat Pump and Innovative Ground-Source Air Heat Pump in a Cold Climate. J. Ind. Ecol. 2015 , 19 , 61–70. [ Google Scholar ] [ CrossRef ]
• Krommweh, M.S.; Rösmann, P.; Büscher, W. Investigation of heating and cooling potential of a modular housing system for fattening pigs with integrated geothermal heat exchanger. Biosyst. Eng. 2014 , 121 , 118–129. [ Google Scholar ] [ CrossRef ]
• Zajch, A.; Gough, W.A.; Chiesa, G. Earth–Air Heat Exchanger Geo-Climatic Suitability for Projected Climate Change Scenarios in the Americas. Sustainability 2020 , 12 , 10613. [ Google Scholar ] [ CrossRef ]
• Lim, T.H.; De Kleine, R.D.; Keoleian, G.A. Energy use and carbon reduction potentials from residential ground source heat pumps considering spatial and economic barriers. Energy Build. 2016 , 128 , 287–304. [ Google Scholar ] [ CrossRef ]
• Greening, B.; Azapagic, A. Domestic heat pumps: Life cycle environmental impacts and potential implications for the UK. Energy 2012 , 39 , 205–217. [ Google Scholar ] [ CrossRef ]
• Guinée, J.B.; Gorrée, M.; Heijungs, R.; Huppes, G.; Kleijn, R.; De Koning, A.; Van Oers, L.; Sleeswijk, A.W.; Suh, S.; Udo de Haes, H.A. Life Cycle Assessment: An Operational Guide to the ISO Standards. 2001. Available online: https://www.universiteitleiden.nl/binaries/content/assets/science/cml/publicaties_pdf/new-dutch-lca-guide/part1.pdf (accessed on 21 March 2023).
• Hauschild, M.Z.; Rosenbaum, R.K.; Olsen, S.I. Life Cycle Assessment: Theory and Practice ; Springer: New York, NY, USA, 2017; ISBN 978-3-319-56475-3. [ Google Scholar ]
• Parisi, M.L.; Douziech, M.; Tosti, L.; Pérez-López, P.; Mendecka, B.; Ulgiati, S.; Fiaschi, D.; Manfrida, G.; Blanc, I. Definition of LCA Guidelines in the Geothermal Sector to Enhance Result Comparability. Energies 2020 , 13 , 3534. [ Google Scholar ] [ CrossRef ]
• Islam, M.M.; Mun, H.-S.; Bostami, A.B.M.R.; Ahmed, S.T.; Park, K.-J.; Yang, C.-J. Evaluation of a ground source geothermal heat pump to save energy and reduce CO2 and noxious gas emissions in a pig house. Energy Build. 2016 , 111 , 446–454. [ Google Scholar ] [ CrossRef ]
• Alberti, L.; Antelmi, M.; Angelotti, A.; Formentin, G. Geothermal heat pumps for sustainable farm climatization and field irrigation. Agric. Water Manag. 2018 , 195 , 187–200. [ Google Scholar ] [ CrossRef ]
• Choi, H.C.; Salim, H.M.; Akter, N.; Na, J.C.; Kang, H.K.; Kim, M.J.; Kim, D.W.; Bang, H.T.; Chae, H.S.; Suh, O.S. Effect of heating system using a geothermal heat pump on the production performance and housing environment of broiler chickens. Poult. Sci. 2012 , 91 , 275–281. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Costantino, A.; Fabrizio, E.; Ghiggini, A.; Bariani, M. Climate control in broiler houses: A thermal model for the calculation of the energy use and indoor environmental conditions. Energy Build. 2018 , 169 , 110–126. [ Google Scholar ] [ CrossRef ]
• Wang, Y.; Li, B.; Liang, C.; Zheng, W. Dynamic simulation of thermal load and energy efficiency in poultry buildings in the cold zone of China. Comput. Electron. Agric. 2020 , 168 , 105127. [ Google Scholar ] [ CrossRef ]
• Tyris, D.; Gkountas, A.; Bakalis, P.; Panagakis, P.; Manolakos, D. A Dynamic Heat Pump Model for Indoor Climate Control of a Broiler House. Energies 2023 , 16 , 2770. [ Google Scholar ] [ CrossRef ]
• Izar, J.; Jaramillo, P.; Griffin, W.; Small, M. Impacts of projected climate change scenarios on heating and cooling demand for industrial broiler chicken farming in the Eastern U.S. J. Clean. Prod. 2020 , 255 , 120306. [ Google Scholar ] [ CrossRef ]
• Cui, Y.; Theo, E.; Gurler, T.; Su, Y.; Saffa, R. A comprehensive review on renewable and sustainable heating systems for poultry farming. Int. J. Low-Carbon Technol. 2020 , 15 , 121–142. [ Google Scholar ] [ CrossRef ]
• Giner-Santonja, G.; Georgitzikis, K.; Scalet, B.; Montobbio, P.; Roudier, S.; Sancho, L. Best Available Techniques (BAT) Reference Document for the Intensive Rearing of Poultry or Pigs. 2017. Available online: https://op.europa.eu/en/publication-detail/-/publication/f673b352-62c0-11e7-b2f2-01aa75ed71a1/language-en (accessed on 12 February 2023).
• Blanes-Vidal, V.; Fitas, V.; Torres, A. Differential pressure as a control parameter for ventilation in poultry houses: Effect on air velocity in the zone occupied by animals. Span. J. Agric. Res. 2007 , 5 , 31–37. [ Google Scholar ] [ CrossRef ]
• Kharseh, M.; Nordell, B. Sustainable heating and cooling systems for agriculture. Int. J. Energy Res. 2011 , 35 , 415–422. [ Google Scholar ] [ CrossRef ]
• Boutera, Y.; Boultif, N.; Rouag, A.; Beldjani, C.; Moummi, N. Performance of earth-air heat exchanger in cooling, heating, and reducing carbon emissions of an industrial poultry farm: A case study. Energy Sources Part Recovery Util. Environ. Eff. 2022 , 44 , 9564–9583. [ Google Scholar ] [ CrossRef ]
• ISO 13790 ; Thermal Performance of Buildings—Calculation of Energy Use for Space Heating. International Organization for Standardization: Geneva, Switzerland, 2008. Available online: https://www.iso.org/standard/41974.html (accessed on 6 May 2023).
• Costantino, A.; Fabrizio, E.; Villagrá, A.; Estellés, F.; Calvet, S. The reduction of gas concentrations in broiler houses through ventilation: Assessment of the thermal and electrical energy consumption. Biosyst. Eng. 2020 , 199 , 135–148. [ Google Scholar ] [ CrossRef ]
• Costantino, A.; Calvet, S.; Fabrizio, E. Identification of energy-efficient solutions for broiler house envelopes through a primary energy approach. J. Clean. Prod. 2021 , 312 , 127639. [ Google Scholar ] [ CrossRef ]
• Tan, H.; Yan, W.; Ren, Z.; Wang, Q.; Mohamed, M.A. Distributionally robust operation for integrated rural energy systems with broiler houses. Energy 2022 , 254 , 124398. [ Google Scholar ] [ CrossRef ]
• Costantino, A. Development, Validation, and Application of Building Energy Simulation Models for Livestock Houses: A Systematic Review. Agriculture 2023 , 13 , 2280. [ Google Scholar ] [ CrossRef ]
• Costantino, A.; Comba, L.; Cornale, P.; Fabrizio, E. Energy impact of climate control in pig farming: Dynamic simulation and experimental validation. Appl. Energy 2022 , 309 , 118457. [ Google Scholar ] [ CrossRef ]
• Costantino, A.; Comba, L.; Sicardi, G.; Bariani, M.; Fabrizio, E. Energy performance and climate control in mechanically ventilated greenhouses: A dynamic modelling-based assessment and investigation. Appl. Energy 2021 , 288 , 116583. [ Google Scholar ] [ CrossRef ]
• Michalak, P. Corrigendum to “The simple hourly method of EN ISO 13790 standard in Matlab/Simulink: A comparative study for the climatic conditions of Poland” [Energy 75 (2015) 568–578]. Energy 2014 , 88 , 973. [ Google Scholar ] [ CrossRef ]
• Pedersen, S.; Sällvik, K. 4th Report of Working Group on Climatization of Animal Houses: Heat and Moisture Production at Animal and House Levels ; Research Centre Bygholm, Danish Institute of Agricultural Sciences: Horsens, Denmark, 2002; ISBN 978-87-88976-60-1. [ Google Scholar ]
• Lohmann Breeders GmbH. Management Guide Cage Housing Systems. 2021; Cuxhaven, Germany. Available online: https://lohmann-breeders.com/management-guide/cage-housing-download/ (accessed on 21 March 2023).
• Agriculture and Agri-Food Canada. Canadian Farm Building Handbook (1988). Available online: https://publications.gc.ca/collections/collection_2014/aac-aafc/agrhist/A15-1822-1988-eng.pdf (accessed on 10 May 2023).
• Canadian Commission on Building and Fire Codes; National Research Council of Canada. National Building Code of Canada 2015. 2018, Volume 1. Available online: https://nrc.canada.ca/en/certifications-evaluations-standards/codes-canada/codes-canada-publications/national-building-code-canada-2015 (accessed on 15 May 2023).
• Zhao, Y.; Xin, H.; Shepherd, T.A.; Hayes, M.D.; Stinn, J.P. Modelling ventilation rate, balance temperature and supplemental heat need in alternative vs. conventional laying-hen housing systems. Biosyst. Eng. 2013 , 115 , 311–323. [ Google Scholar ] [ CrossRef ]
• Rosa, E.; Arriaga, H.; Calvet, S.; Merino, P. Assessing ventilation rate measurements in a mechanically ventilated laying hen facility. Poult. Sci. 2019 , 98 , 1211–1221. [ Google Scholar ] [ CrossRef ]
• Shahbandeh, M. Egg Industry: Registered Layers Canada 2021. 2022. Available online: https://www.statista.com/statistics/527646/egg-farmers-canada-laying-registered-hens-province/ (accessed on 17 January 2023).
• National Farm Animal Care Council (NFACC). Layers Code of Practice ; National Farm Animal Care Council: Lacombe, AB, Canada, 2017. [ Google Scholar ]
• Farm & Food Care. Facts and Figures about Canadian Hens and Eggs 2016. Available online: https://www.getcracking.ca/sites/default/files/media/document/Egg-Fact-Sheet.pdf (accessed on 12 May 2023).
• Chen, D.; Chen, H.W. Using the Köppen classification to quantify climate variation and change: An example for 1901–2010. Environ. Dev. 2013 , 6 , 69–79. [ Google Scholar ] [ CrossRef ]
• Siu, C.Y.; Liao, Z. Is building energy simulation based on TMY representative: A comparative simulation study on doe reference buildings in Toronto with typical year and historical year type weather files. Energy Build. 2020 , 211 , 109760. [ Google Scholar ] [ CrossRef ]
• Renné, D. Resource assessment and site selection for solar heating and cooling systems. In Advances in Solar Heating and Cooling ; Elsevier: Amsterdam, The Netherlands, 2016; pp. 13–41. ISBN 978-0-08-100301-5. [ Google Scholar ] [ CrossRef ]
• Gueymard, C. Solar Radiation Resource: Measurement, Modeling, and Methods. In Reference Module in Earth Systems and Environmental Sciences ; Elsevier: Amsterdam, The Netherlands, 2021; ISBN 978-0-12-409548-9. [ Google Scholar ]
• Hall, I.J.; Prairie, R.R.; Anderson, H.E.; Boes, E.C. Generation of a Typical Meteorological Year ; Sandia Labs.: Albuquerque, NM, USA, 1978. [ Google Scholar ]
• Hosseini, M.; Lee, B.; Vakilinia, S. Energy performance of cool roofs under the impact of actual weather data. Energy Build. 2017 , 145 , 284–292. [ Google Scholar ] [ CrossRef ]
• U.S. Department of Energy–Building Technologies Office EnergyPlus–Weather Data. Available online: https://energyplus.net/weather (accessed on 12 May 2023).
• Moher, D.; Liberati, A.; Tetzlaff, J.; Altman, D.G. Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. Ann. Intern. Med. 2009 , 151 , 264–269. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Cedar Lake Ventures, Inc. The Weather Year Round Anywhere on Earth–Weather Spark. Available online: https://weatherspark.com/ (accessed on 5 May 2023).
• Heide, V.; Thingbø, H.S.; Lien, A.G.; Georges, L. Economic and Energy Performance of Heating and Ventilation Systems in Deep Retrofitted Norwegian Detached Houses. Energies 2022 , 15 , 7060. [ Google Scholar ] [ CrossRef ]
• David, I.; Stefanescu, C.; Vlad, I. Efficiency Assessment of Ground-Source Heat Pumps in Comparison with Classical Heating System. In Proceedings of the 15th International Multidisciplinary Scientific GeoConference SGEM 2015, Albena, Bulgaria, 18–24 June 2015. [ Google Scholar ]
• Bloom, E.; Tinjum, J. Fully Instrumented Life-Cycle Analyses for a Residential Geo-Exchange System. In Proceedings of the Geo-Chicago 2016, Chicago, IL, USA, 14–18 August 2016; p. 124. [ Google Scholar ]
• Rodriguez, J.; Bangueses, I.; Castro, M. Life Cycle Analysis of a Geothermal Heatpump Installation and Comparison with a Conventional Fuel Boiler System in a Nursery School in Galicia (Spain). EPJ Web Conf. 2012 , 33 , 05003. [ Google Scholar ] [ CrossRef ]
• Government of Canada, I. Technology Readiness Level (TRL) Assessment Tool. Available online: https://ised-isde.canada.ca/site/clean-growth-hub/en/technology-readiness-level-trl-assessment-tool (accessed on 23 January 2023).
• ASHRAE handbook–Fundamentals (SI Edition) ; ASHRAE: Atlanta, GA, USA, 2017; ISBN 978-1-936504-46-6.
• Elnagar, E.; Köhler, B. Reduction of the Energy Demand with Passive Approaches in Multifamily Nearly Zero-Energy Buildings Under Different Climate Conditions. Front. Energy Res. 2020 , 8 , 545272. [ Google Scholar ] [ CrossRef ]
• Al-Shamkhee, D.; Al-Aasam, A.B.; Al-Waeli, A.H.A.; Abusaibaa, G.Y.; Moria, H. Passive cooling techniques for ventilation: An updated review. Renew. Energy Environ. Sustain. 2022 , 7 , 23. [ Google Scholar ] [ CrossRef ]
• Oropeza-Perez, I.; Østergaard, P.A. Active and passive cooling methods for dwellings: A review. Renew. Sustain. Energy Rev. 2018 , 82 , 531–544. [ Google Scholar ] [ CrossRef ]
• Kim, E.; Lee, J.; Jeong, Y.; Hwang, Y.; Lee, S.; Park, N. Performance evaluation under the actual operating condition of a vertical ground source heat pump system in a school building. Energy Build. 2012 , 50 , 1–6. [ Google Scholar ] [ CrossRef ]
• Urchueguía, J.F.; Zacarés, M.; Corberán, J.M.; Montero, Á.; Martos, J.; Witte, H. Comparison between the energy performance of a ground coupled water to water heat pump system and an air to water heat pump system for heating and cooling in typical conditions of the European Mediterranean coast. Energy Convers. Manag. 2008 , 49 , 2917–2923. [ Google Scholar ] [ CrossRef ]
• Violante, A.C.; Donato, F.; Guidi, G.; Proposito, M. Comparative life cycle assessment of the ground source heat pump vs air source heat pump. Renew. Energy 2022 , 188 , 1029–1037. [ Google Scholar ] [ CrossRef ]
• Di Perna, C.; Magri, G.; Giuliani, G.; Serenelli, G. Experimental assessment and dynamic analysis of a hybrid generator composed of an air source heat pump coupled with a condensing gas boiler in a residential building. Appl. Therm. Eng. 2015 , 76 , 86–97. [ Google Scholar ] [ CrossRef ]
• Sevindik, S.; Spataru, C. An Integrated Methodology for Scenarios Analysis of Low Carbon Technologies Uptake towards a Circular Economy: The Case of Orkney. Energies 2023 , 16 , 419. [ Google Scholar ] [ CrossRef ]
• Wu, W.; Skye, H.M. Net-zero nation: HVAC and PV systems for residential net-zero energy buildings across the United States. Energy Convers. Manag. 2018 , 177 , 605–628. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Aresti, L.; Florides, G.A.; Skaliontas, A.; Christodoulides, P. Environmental Impact of Ground Source Heat Pump Systems: A Comparative Investigation from South to North Europe. Front. Built Environ. 2022 , 8 , 914227. [ Google Scholar ] [ CrossRef ]
• Naumann, G.; Schropp, E.; Gaderer, M. Life Cycle Assessment of an Air-Source Heat Pump and a Condensing Gas Boiler Using an Attributional and a Consequential Approach. Procedia CIRP 2022 , 105 , 351–356. [ Google Scholar ] [ CrossRef ]
• Madonna, F.; Bazzocchi, F. Annual performances of reversible air-to-water heat pumps in small residential buildings. Energy Build. 2013 , 65 , 299–309. [ Google Scholar ] [ CrossRef ]
• Li, H.; Ni, L.; Yao, Y.; Sun, C. Annual performance experiments of an earth-air heat exchanger fresh air-handling unit in severe cold regions: Operation, economic and greenhouse gas emission analyses. Renew. Energy 2020 , 146 , 25–37. [ Google Scholar ] [ CrossRef ]
• Liu, X.; Hong, T. Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems. Energy Build. 2010 , 42 , 584–589. [ Google Scholar ] [ CrossRef ]
• Sevindik, S.; Spataru, C.; Domenech Aparisi, T.; Bleischwitz, R. A Comparative Environmental Assessment of Heat Pumps and Gas Boilers towards a Circular Economy in the UK. Energies 2021 , 14 , 3027. [ Google Scholar ] [ CrossRef ]
• Zhang, Z.; Wang, J.; Yang, M.; Gong, K.; Yang, M. Environmental and Economic Analysis of Heating Solutions for Rural Residences in China. Sustainability 2022 , 14 , 5117. [ Google Scholar ] [ CrossRef ]
• Aresti, L.; Christodoulides, P.; Florides, G.A. An investigation on the environmental impact of various Ground Heat Exchangers configurations. Renew. Energy 2021 , 171 , 592–605. [ Google Scholar ] [ CrossRef ]
• Sameer, H.; Behem, G.; Mostert, C.; Bringezu, S. Comparative Analysis of Resource and Climate Footprints for Different Heating Systems in Building Information Modeling. Buildings 2022 , 12 , 1824. [ Google Scholar ] [ CrossRef ]
• Ahmed, S.F.; Khan, M.M.K.; Amanullah, M.T.O.; Rasul, M.G.; Hassan, N.M.S. Thermal performance of building-integrated horizontal earth-air heat exchanger in a subtropical hot humid climate. Geothermics 2022 , 99 , 102313. [ Google Scholar ] [ CrossRef ]
• Uddin, M.S.; Ahmed, R.; Rahman, M. Performance evaluation and life cycle analysis of earth to air heat exchanger in a developing country. Energy Build. 2016 , 128 , 254–261. [ Google Scholar ] [ CrossRef ]
• Khaled, H.; Benatiallah, A.; Abdelkader, H.; Belatrache, D. Efficiency Assessment of an Earth-Air Heat Exchanger System for Passive Cooling in Three Different Regions–the Algerian Case. FME Trans. 2021 , 49 , 1035–1046. [ Google Scholar ] [ CrossRef ]
• Lee, K.H.; Strand, R.K. The cooling and heating potential of an earth tube system in buildings. Energy Build. 2008 , 40 , 486–494. [ Google Scholar ] [ CrossRef ]
• Ramírez-Dávila, L.; Xamán, J.; Arce, J.; Álvarez, G.; Hernández-Pérez, I. Numerical study of earth-to-air heat exchanger for three different climates. Energy Build. 2014 , 76 , 238–248. [ Google Scholar ] [ CrossRef ]
• Vaz, J.; Sattler, M.A.; dos Santos, E.D.; Isoldi, L.A. Experimental and numerical analysis of an earth–air heat exchanger. Energy Build. 2011 , 43 , 2476–2482. [ Google Scholar ] [ CrossRef ]
• Bisoniya, T.S.; Kumar, A.; Baredar, P. Energy metrics of earth–air heat exchanger system for hot and dry climatic conditions of India. Energy Build. 2015 , 86 , 214–221. [ Google Scholar ] [ CrossRef ]
• Rangarajan, V.; Singh, R.; Kaushal, P. Model development and performance evaluation of an earth air heat exchanger under a constrained urban environment. Model. Earth Syst. Environ. 2019 , 5 , 143–158. [ Google Scholar ] [ CrossRef ]
• Eicker, U.; Vorschulze, C. Potential of geothermal heat exchangers for office building climatisation. Renew. Energy 2009 , 34 , 1126–1133. [ Google Scholar ] [ CrossRef ]
• Grosso, M.; Chiesa, G. Horizontal Earth-to-air Heat Exchanger in Imola, Italy. A 30-Month- Long Monitoring Campaign. Energy Procedia 2015 , 78 , 73–78. [ Google Scholar ] [ CrossRef ]
• Chiesa, G.; Simonetti, M.; Grosso, M. A 3-field earth-heat-exchange system for a school building in Imola, Italy: Monitoring results. Renew. Energy 2014 , 62 , 563–570. [ Google Scholar ] [ CrossRef ]
• Bisoniya, T.; Kumar, A.; Baredar, P. Heating potential evaluation of earth-air heat exchanger system for winter season. J. Build. Phys. 2015 , 39 , 242–260. [ Google Scholar ] [ CrossRef ]
• Fazlikhani, F.; Goudarzi, H.; Solgi, E. Numerical analysis of the efficiency of earth to air heat exchange systems in cold and hot-arid climates. Energy Convers. Manag. 2017 , 148 , 78–89. [ Google Scholar ] [ CrossRef ]
• Shojaee, S.M.N.; Malek, K. Earth-to-air heat exchangers cooling evaluation for different climates of Iran. Sustain. Energy Technol. Assess. 2017 , 23 , 111–120. [ Google Scholar ] [ CrossRef ]
• Pfafferott, J. Evaluation of earth-to-air heat exchangers with a standardised method to calculate energy efficiency. Energy Build. 2003 , 35 , 971–983. [ Google Scholar ] [ CrossRef ]
• Ascione, F.; Bellia, L.; Minichiello, F. Earth-to-air heat exchangers for Italian climates. Renew. Energy 2011 , 36 , 2177–2188. [ Google Scholar ] [ CrossRef ]
• Congedo, P.M.; Lorusso, C.; De Giorgi, M.G.; Marti, R.; D’Agostino, D. Horizontal Air-Ground Heat Exchanger Performance and Humidity Simulation by Computational Fluid Dynamic Analysis. Energies 2016 , 9 , 930. [ Google Scholar ] [ CrossRef ]
• Dabaieh, M.; Serageldin, A.A. Earth air heat exchanger, Trombe wall and green wall for passive heating and cooling in premium passive refugee house in Sweden. Energy Convers. Manag. 2020 , 209 , 112555. [ Google Scholar ] [ CrossRef ]
• Abusoglu, A.; Sedeeq, M.S. Comparative exergoenvironmental analysis and assessment of various residential heating systems. Energy Build. 2013 , 62 , 268–277. [ Google Scholar ] [ CrossRef ]
• Hunter, A. Comparative Life Cycle Assessment: Ground Source Heat Pump System versus Gas Furnace and Air Conditioner System. Master’s Thesis, Ryerson University, Toronto, ON, Canada, 2017. [ Google Scholar ]
• Blomqvist, S.; La Fleur, L.; Amiri, S.; Rohdin, P.; Ödlund, L. The Impact on System Performance When Renovating a Multifamily Building Stock in a District Heated Region. Sustainability 2019 , 11 , 2199. [ Google Scholar ] [ CrossRef ]
• Wąs, K.; Radon, J.; Sadłowska-Sałęga, A. Thermal Comfort—Case Study in a Lightweight Passive House. Energies 2022 , 15 , 4687. [ Google Scholar ] [ CrossRef ]
• Borge-Diez, D.; Colmenar-Santos, A.; Pérez-Molina, C.; López-Rey, Á. Geothermal source heat pumps under energy services companies finance scheme to increase energy efficiency and production in stockbreeding facilities. Energy 2015 , 88 , 821–836. [ Google Scholar ] [ CrossRef ]
• Barbhuiya, S.; Barbhuiya, S. Reducing CO 2 Emissions in a Typical 60 Years Old Detached House in London. J. Green Build. 2013 , 8 , 3–15. [ Google Scholar ] [ CrossRef ]
• Sankelo, P.; Ahmed, K.; Mikola, A.; Kurnitski, J. Renovation Results of Finnish Single-Family Renovation Subsidies: Oil Boiler Replacement with Heat Pumps. Energies 2022 , 15 , 7620. [ Google Scholar ] [ CrossRef ]
• Cadelano, G.; Cicolin, F.; Emmi, G.; Mezzasalma, G.; Poletto, D.; Galgaro, A.; Bernardi, A. Improving the Energy Efficiency, Limiting Costs and Reducing CO2 Emissions of a Museum Using Geothermal Energy and Energy Management Policies. Energies 2019 , 12 , 3192. [ Google Scholar ] [ CrossRef ]
• Carvalho, A.D.; Mendrinos, D.; De Almeida, A.T. Ground source heat pump carbon emissions and primary energy reduction potential for heating in buildings in Europe—Results of a case study in Portugal. Renew. Sustain. Energy Rev. 2015 , 45 , 755–768. [ Google Scholar ] [ CrossRef ]
• Huang, B.; Mauerhofer, V. Life cycle sustainability assessment of ground source heat pump in Shanghai, China. J. Clean. Prod. 2016 , 119 , 207–214. [ Google Scholar ] [ CrossRef ]
• Lu, J.; Chen, M. The Analysis and Simulation on Operating Characteristics of GSHP in Summer. J. Supercond. Nov. Magn. 2010 , 23 , 1091–1093. [ Google Scholar ] [ CrossRef ]
• Luo, J.; Rohn, J.; Bayer, M.; Priess, A.; Wilkmann, L.; Xiang, W. Heating and cooling performance analysis of a ground source heat pump system in Southern Germany. Geothermics 2015 , 53 , 57–66. [ Google Scholar ] [ CrossRef ]
• Michopoulos, A.; Bozis, D.; Kikidis, P.; Papakostas, K.; Kyriakis, N.A. Three-years operation experience of a ground source heat pump system in Northern Greece. Energy Build. 2007 , 39 , 328–334. [ Google Scholar ] [ CrossRef ]
• Montagud, C.; Corberán, J.M.; Montero, Á.; Urchueguía, J.F. Analysis of the energy performance of a ground source heat pump system after five years of operation. Energy Build. 2011 , 43 , 3618–3626. [ Google Scholar ] [ CrossRef ]
• Szreder, M. A field study of the performance of a heat pump installed in a low energy house. Appl. Therm. Eng. 2014 , 71 , 596–606. [ Google Scholar ] [ CrossRef ]
• Zhai, X.Q.; Yang, Y. Experience on the application of a ground source heat pump system in an archives building. Energy Build. 2011 , 43 , 3263–3270. [ Google Scholar ] [ CrossRef ]
• Zhai, X.Q.; Cheng, X.W.; Wang, R.Z. Heating and cooling performance of a minitype ground source heat pump system. Appl. Therm. Eng. 2017 , 111 , 1366–1370. [ Google Scholar ] [ CrossRef ]
• Saner, D.; Juraske, R.; Kübert, M.; Blum, P.; Hellweg, S.; Bayer, P. Is it only CO 2 that matters? A life cycle perspective on shallow geothermal systems. Renew. Sustain. Energy Rev. 2010 , 14 , 1798–1813. [ Google Scholar ] [ CrossRef ]
• Smith, M.; Bevacqua, A.; Tembe, S.; Lal, P. Life cycle analysis (LCA) of residential ground source heat pump systems: A comparative analysis of energy efficiency in New Jersey. Sustain. Energy Technol. Assess. 2021 , 47 , 101364. [ Google Scholar ] [ CrossRef ]
• Chang, Y.; Gu, Y.; Zhang, L.; Wu, C.; Liang, L. Energy and environmental implications of using geothermal heat pumps in buildings: An example from north China. J. Clean. Prod. 2017 , 167 , 484–492. [ Google Scholar ] [ CrossRef ]
• İnallı, M.; Esen, H. Experimental thermal performance evaluation of a horizontal ground-source heat pump system. Appl. Therm. Eng. 2004 , 24 , 2219–2232. [ Google Scholar ] [ CrossRef ]
• Lee, J.-U.; Kim, T.; Leigh, S.-B. Thermal performance analysis of a ground-coupled heat pump integrated with building foundation in summer. Energy Build. 2013 , 59 , 37–43. [ Google Scholar ] [ CrossRef ]
• Naili, N.; Hazami, M.; Attar, I.; Farhat, A. Assessment of surface geothermal energy for air conditioning in northern Tunisia: Direct test and deployment of ground source heat pump system. Energy Build. 2016 , 111 , 207–217. [ Google Scholar ] [ CrossRef ]
• Widiatmojo, A.; Uchida, Y.; Fujii, H.; Kosukegawa, H.; Takashima, I.; Shimada, Y.; Chotpantarat, S.; Charusiri, P.; Tran, T.T. Numerical simulations on potential application of ground source heat pumps with vertical ground heat exchangers in Bangkok and Hanoi. Energy Rep. 2021 , 7 , 6932–6944. [ Google Scholar ] [ CrossRef ]
• Esen, H.; Inalli, M.; Esen, M. Technoeconomic appraisal of a ground source heat pump system for a heating season in eastern Turkey. Energy Convers. Manag. 2006 , 47 , 1281–1297. [ Google Scholar ] [ CrossRef ]
• Neves, R.; Cho, H.; Zhang, J. Techno-economic analysis of geothermal system in residential building in Memphis, Tennessee. J. Build. Eng. 2020 , 27 , 100993. [ Google Scholar ] [ CrossRef ]
• Blumsack, S.; Brownson, J.; Witmer, L. Efficiency, Economic and Environmental Assessment of Ground Source Heat Pumps in Central Pennsylvania. In Proceedings of the 2009 42nd Hawaii International Conference on System Sciences, Waikoloa, HI, USA, 5–8 January 2009; pp. 1–7. [ Google Scholar ]
• Sivasakthivel, T.; Murugesan, K.; Sahoo, P.K. Study of technical, economical and environmental viability of ground source heat pump system for Himalayan cities of India. Renew. Sustain. Energy Rev. 2015 , 48 , 452–462. [ Google Scholar ] [ CrossRef ]
• Wang, Z.; Zhang, L.; Jiang, C.; Xiao, C.; Wang, L.; Hu, W.; Yu, M. On the use of techno-economic evaluation on typical integrated energy technologies matching different companies. J. Eng. 2021 , 2021 , 534–540. [ Google Scholar ] [ CrossRef ]
• D’Arpa, S.; Colangelo, G.; Starace, G.; Petrosillo, I.; Bruno, D.E.; Uricchio, V.; Zurlini, G. Heating requirements in greenhouse farming in southern Italy: Evaluation of ground-source heat pump utilization compared to traditional heating systems. Energy Effic. 2016 , 9 , 1065–1085. [ Google Scholar ] [ CrossRef ]
• Sadeghi, H.; Ijaz, A.; Singh, R.M. Current status of heat pumps in Norway and analysis of their performance and payback time. Sustain. Energy Technol. Assess. 2022 , 54 , 102829. [ Google Scholar ] [ CrossRef ]
• Wu, W.; Skye, H.M.; Domanski, P.A. Selecting HVAC systems to achieve comfortable and cost-effective residential net-zero energy buildings. Appl. Energy 2018 , 212 , 577–591. [ Google Scholar ] [ CrossRef ]
• Widiatmojo, A.; Chokchai, S.; Takashima, I.; Uchida, Y.; Yasukawa, K.; Chotpantarat, S.; Charusiri, P. Ground-Source Heat Pumps with Horizontal Heat Exchangers for Space Cooling in the Hot Tropical Climate of Thailand. Energies 2019 , 12 , 1274. [ Google Scholar ] [ CrossRef ]
• Wang, H.; Dai, Y.; Yang, S.; Li, T.; Luo, J.; Sun, B.; Duan, M.; Ma, J.; Yin, Z.; Huang, Y. Predicting climate anomalies: A real challenge. Atmos. Ocean. Sci. Lett. 2022 , 15 , 100115. [ Google Scholar ] [ CrossRef ]
• Shah, V.P.; Debella, D.C.; Ries, R.J. Life cycle assessment of residential heating and cooling systems in four regions in the United States. Energy Build. 2008 , 40 , 503–513. [ Google Scholar ] [ CrossRef ]
• Cheng, M.-Y.; Chiu, K.-C.; Lien, L.-C.; Wu, Y.-W.; Lin, J.-J. Economic and energy consumption analysis of smart building—MEGA house. Build. Environ. 2016 , 100 , 215–226. [ Google Scholar ] [ CrossRef ]
• Zhou, Y.; Ni, M. Feasibility study on applications of solar chimney and earth tube systems for BEAM/LEED assessment. Int. J. Energy Res. 2016 , 40 , 1207–1220. [ Google Scholar ] [ CrossRef ]
• Aira, R.; Fernández-Seara, J.; Diz, R.; Pardiñas, Á.Á. Experimental analysis of a ground source heat pump in a residential installation after two years in operation. Renew. Energy 2017 , 114 , 1214–1223. [ Google Scholar ] [ CrossRef ]
• Ristimäki, M.; Säynäjoki, A.; Heinonen, J.; Junnila, S. Combining life cycle costing and life cycle assessment for an analysis of a new residential district energy system design. Energy 2013 , 63 , 168–179. [ Google Scholar ] [ CrossRef ]
• Abdel-Salam, M.R.H.; Zaidi, A. Field study of cooling performance of two ground-source heat pumps in Canadian single-family houses. Appl. Therm. Eng. 2021 , 184 , 116294. [ Google Scholar ] [ CrossRef ]
• Bakirci, K. Evaluation of the performance of a ground-source heat-pump system with series GHE (ground heat exchanger) in the cold climate region. Energy 2010 , 35 , 3088–3096. [ Google Scholar ] [ CrossRef ]
• De Carli, M.; Galgaro, A.; Pasqualetto, M.; Zarrella, A. Energetic and economic aspects of a heating and cooling district in a mild climate based on closed loop ground source heat pump. Appl. Therm. Eng. 2014 , 71 , 895–904. [ Google Scholar ] [ CrossRef ]
• Koroneos, C.J.; Nanaki, E.A. Environmental impact assessment of a ground source heat pump system in Greece. Geothermics 2017 , 65 , 1–9. [ Google Scholar ] [ CrossRef ]
• Zhai, Y.; Zhang, T.; Tan, X.; Wang, G.; Duan, L.; Shi, Q.; Ji, C.; Bai, Y.; Shen, X.; Meng, J.; et al. Environmental impact assessment of ground source heat pump system for heating and cooling: A case study in China. Int. J. Life Cycle Assess. 2022 , 27 , 395–408. [ Google Scholar ] [ CrossRef ]
• Minea, V. Ground-source heat pumps: Energy efficiency for two Canadian schools. ASHRAE J. 2006 , 48 , 28–38. [ Google Scholar ]
• Wang, W.; Feng, Y.C.; Zhu, J.H.; Li, L.T.; Guo, Q.C.; Lu, W.P. Performances of air source heat pump system for a kind of mal-defrost phenomenon appearing in moderate climate conditions. Appl. Energy 2013 , 112 , 1138–1145. [ Google Scholar ] [ CrossRef ]
• Felius, L.C.; Hamdy, M.; Dessen, F.; Hrynyszyn, B.D. Upgrading the Smartness of Retrofitting Packages towards Energy-Efficient Residential Buildings in Cold Climate Countries: Two Case Studies. Buildings 2020 , 10 , 200. [ Google Scholar ] [ CrossRef ]
• Congedo, P.M.; Baglivo, C.; Bonuso, S.; D’Agostino, D. Numerical and experimental analysis of the energy performance of an air-source heat pump (ASHP) coupled with a horizontal earth-to-air heat exchanger (EAHX) in different climates. Geothermics 2020 , 87 , 101845. [ Google Scholar ] [ CrossRef ]
• Bonamente, E.; Aquino, A. Life-Cycle Assessment of an Innovative Ground-Source Heat Pump System with Upstream Thermal Storage. Energies 2017 , 10 , 1854. [ Google Scholar ] [ CrossRef ]
• Hepbasli, A. Performance evaluation of a vertical ground-source heat pump system in Izmir, Turkey. Int. J. Energy Res. 2002 , 26 , 1121–1139. [ Google Scholar ] [ CrossRef ]
• Hepbasli, A.; Akdemir, O.; Hancioglu, E. Experimental study of a closed loop vertical ground source heat pump system. Energy Convers. Manag. 2003 , 44 , 527–548. [ Google Scholar ] [ CrossRef ]
• Hepbasli, A.; Akdemir, O. Energy and exergy analysis of a ground source (geothermal) heat pump system. Energy Convers. Manag. 2004 , 45 , 737–753. [ Google Scholar ] [ CrossRef ]
• Seo, Y.; Seo, U.-J. Ground source heat pump (GSHP) systems for horticulture greenhouses adjacent to highway interchanges: A case study in South Korea. Renew. Sustain. Energy Rev. 2021 , 135 , 110194. [ Google Scholar ] [ CrossRef ]
• Latorre-Biel, J.-I.; Jimémez, E.; García, J.L.; Martínez, E.; Jiménez, E.; Blanco, J. Replacement of electric resistive space heating by an air-source heat pump in a residential application. Environmental amortization. Build. Environ. 2018 , 141 , 193–205. [ Google Scholar ] [ CrossRef ]
• Spitler, J.D.; Gehlin, S. Measured Performance of a Mixed-Use Commercial-Building Ground Source Heat Pump System in Sweden. Energies 2019 , 12 , 2020. [ Google Scholar ] [ CrossRef ]
• Xiao, B.; He, L.; Zhang, S.; Kong, T.; Hu, B.; Wang, R.Z. Comparison and analysis on air-to-air and air-to-water heat pump heating systems. Renew. Energy 2020 , 146 , 1888–1896. [ Google Scholar ] [ CrossRef ]
• Bahlawan, H.; Poganietz, W.-R.; Spina, P.R.; Venturini, M. Cradle-to-gate life cycle assessment of energy systems for residential applications by accounting for scaling effects. Appl. Therm. Eng. 2020 , 171 , 115062. [ Google Scholar ] [ CrossRef ]
• Slorach, P.C.; Stamford, L. Net zero in the heating sector: Technological options and environmental sustainability from now to 2050. Energy Convers Manag. 2021 , 230 , 113838. [ Google Scholar ] [ CrossRef ]
• Hong, T.; Kim, J.; Chae, M.; Park, J.; Jeong, J.; Lee, M. Sensitivity Analysis on the Impact Factors of the GSHP System Considering Energy Generation and Environmental Impact Using LCA. Sustainability 2016 , 8 , 376. [ Google Scholar ] [ CrossRef ]
• Gan, G. Simulation of dynamic interactions of the earth–air heat exchanger with soil and atmosphere for preheating of ventilation air. Appl. Energy 2015 , 158 , 118–132. [ Google Scholar ] [ CrossRef ]
• Li, Y.; Liu, M.; Tang, Y.; Jia, Y.; Wang, Q.; Ma, Q.; Hong, J.; Zuo, J.; Yuan, X. Life cycle impact of winter heating in rural China from the perspective of environment, economy, and user experience. Energy Convers. Manag. 2022 , 269 , 116156. [ Google Scholar ] [ CrossRef ]
• Gan, G. Impacts of dynamic interactions on the predicted thermal performance of earth–air heat exchangers for preheating, cooling and ventilation of buildings. Int. J. Low-Carbon. Technol. 2015 , 12 , ctv029. [ Google Scholar ] [ CrossRef ]
• Hegazi, A.A.; Abdelrehim, O.; Khater, A. Parametric optimization of earth-air heat exchangers (EAHEs) for central air conditioning. Int. J. Refrig. 2021 , 129 , 278–289. [ Google Scholar ] [ CrossRef ]
• Soni, S.K.; Pandey, M.; Bartaria, V.N. Energy metrics of a hybrid earth air heat exchanger system for summer cooling requirements. Energy Build. 2016 , 129 , 1–8. [ Google Scholar ] [ CrossRef ]
• 172. Wang, C.; Xu, A.; Jiao, S.; Zhou, Z.; Zhang, D.; Liu, J.; Ling, J.; Gao, F.; Rameezdeen, R.; Wang, L.; et al. Environmental impact assessment of office building heating and cooling sources: A life cycle approach. J. Clean. Prod. 2020 , 261 , 121140. [ Google Scholar ] [ CrossRef ]
• Benzaama, M.H.; Menhoudj, S.; Lekhal, M.C.; Mokhtari, A.; Attia, S. Multi-objective optimisation of a seasonal solar thermal energy storage system combined with an earth—Air heat exchanger for net zero energy building. Sol. Energy 2021 , 220 , 901–913. [ Google Scholar ] [ CrossRef ]
• Ghosal, M.K.; Tiwari, G.N.; Das, D.K.; Pandey, K.P. Modeling and comparative thermal performance of ground air collector and earth air heat exchanger for heating of greenhouse. Energy Build. 2005 , 37 , 613–621. [ Google Scholar ] [ CrossRef ]
• Al-Ajmi, F.; Loveday, D.L.; Hanby, V.I. The cooling potential of earth–air heat exchangers for domestic buildings in a desert climate. Build. Environ. 2006 , 41 , 235–244. [ Google Scholar ] [ CrossRef ]
• Blum, P.; Campillo, G.; Münch, W.; Kölbel, T. CO 2 savings of ground source heat pump systems—A regional analysis. Renew. Energy 2010 , 35 , 122–127. [ Google Scholar ] [ CrossRef ]
• Hwang, Y.; Lee, J.-K.; Jeong, Y.-M.; Koo, K.-M.; Lee, D.-H.; Kim, I.-K.; Jin, S.-W.; Kim, S.H. Cooling performance of a vertical ground-coupled heat pump system installed in a school building. Renew. Energy 2009 , 34 , 578–582. [ Google Scholar ] [ CrossRef ]
• Chel, A.; Tiwari, G.N. Performance evaluation and life cycle cost analysis of earth to air heat exchanger integrated with adobe building for New Delhi composite climate. Energy Build. 2009 , 41 , 56–66. [ Google Scholar ] [ CrossRef ]
• Pulat, E.; Coskun, S.; Unlu, K.; Yamankaradeniz, N. Experimental study of horizontal ground source heat pump performance for mild climate in Turkey. Energy 2009 , 34 , 1284–1295. [ Google Scholar ] [ CrossRef ]
• Gheysari, A.F.; Holländer, H.M.; Maghoul, P.; Shalaby, A. Sustainability, climate resiliency, and mitigation capacity of geothermal heat pump systems in cold regions. Geothermics 2021 , 91 , 101979. [ Google Scholar ] [ CrossRef ]
• Man, Y.; Yang, H.; Wang, J.; Fang, Z. In situ operation performance test of ground coupled heat pump system for cooling and heating provision in temperate zone. Appl. Energy 2012 , 97 , 913–920. [ Google Scholar ] [ CrossRef ]
• Ozyurt, O.; Ekinci, D.A. Experimental study of vertical ground-source heat pump performance evaluation for cold climate in Turkey. Appl. Energy 2011 , 88 , 1257–1265. [ Google Scholar ] [ CrossRef ]
• D’Agostino, D.; Minichiello, F.; Valentino, A. Contribution of Low Enthalpy Geothermal Energy in the Retrofit of a Single-Family House: A Comparison between Two Technologies. J. Adv. Therm. Sci. Res. 2020 , 7 , 30–39. [ Google Scholar ] [ CrossRef ]
• Abid, M.; Hewitt, N.; Huang, M.-J.; Wilson, C.; Cotter, D. Performance Analysis of the Developed Air Source Heat Pump System at Low-to-Medium and High Supply Temperatures for Irish Housing Stock Heat Load Applications. Sustainability 2021 , 13 , 11753. [ Google Scholar ] [ CrossRef ]
• Kharseh, M.; Al-Khawaja, M.; Suleiman, M.T. Potential of ground source heat pump systems in cooling-dominated environments: Residential buildings. Geothermics 2015 , 57 , 104–110. [ Google Scholar ] [ CrossRef ]
• Zhu, N.; Hu, P.; Wang, W.; Yu, J.; Lei, F. Performance analysis of ground water-source heat pump system with improved control strategies for building retrofit. Renew. Energy 2015 , 80 , 324–330. [ Google Scholar ] [ CrossRef ]
• Karabacak, R.; Güven Acar, Ş.; Kumsar, H.; Gökgöz, A.; Kaya, M.; Tülek, Y. Experimental investigation of the cooling performance of a ground source heat pump system in Denizli, Turkey. Int. J. Refrig. 2011 , 34 , 454–465. [ Google Scholar ] [ CrossRef ]
• Naili, N.; Attar, I.; Hazami, M.; Farhat, A. First in situ operation performance test of ground source heat pump in Tunisia. Energy Convers. Manag. 2013 , 75 , 292–301. [ Google Scholar ] [ CrossRef ]
• Naili, N.; Hazami, M.; Kooli, S.; Farhat, A. Energy and exergy analysis of horizontal ground heat exchanger for hot climatic condition of northern Tunisia. Geothermics 2015 , 53 , 270–280. [ Google Scholar ] [ CrossRef ]
• Yasukawa, K.; Takashima, I.; Uchida, Y.; Tenma, N.; Lorphensri, O. Geothermal heat pump application for space cooling in Kamphaengphet, Thailand. Bull. Geol. Surv. Jpn. 2009 , 60 , 491–501. [ Google Scholar ] [ CrossRef ]
• De Swardt, C.A.; Meyer, J.P. A performance comparison between an air-source and a ground-source reversible heat pump. Int. J. Energy Res. 2001 , 25 , 899–910. [ Google Scholar ] [ CrossRef ]
• Ozgener, O.; Hepbasli, A. Modeling and performance evaluation of ground source (geothermal) heat pump systems. Energy Build. 2007 , 39 , 66–75. [ Google Scholar ] [ CrossRef ]
• Jenkins, D.P.; Tucker, R.; Rawlings, R. Modelling the carbon-saving performance of domestic ground-source heat pumps. Energy Build. 2009 , 41 , 587–595. [ Google Scholar ] [ CrossRef ]
• Lo Russo, S.; Boffa, C.; Civita, M.V. Low-enthalpy geothermal energy: An opportunity to meet increasing energy needs and reduce CO 2 and atmospheric pollutant emissions in Piemonte, Italy. Geothermics 2009 , 38 , 254–262. [ Google Scholar ] [ CrossRef ]
• Chai, L.; Ma, C.; Ni, J.-Q. Performance evaluation of ground source heat pump system for greenhouse heating in northern China. Biosyst. Eng. 2012 , 111 , 107–117. [ Google Scholar ] [ CrossRef ]
• Emmi, G.; Zarrella, A.; De Carli, M.; Moretto, S.; Galgaro, A.; Cultrera, M.; Di Tuccio, M.; Bernardi, A. Ground source heat pump systems in historical buildings: Two Italian case studies. Energy Procedia 2017 , 133 , 183–194. [ Google Scholar ] [ CrossRef ]
• Ascione, F.; D’Agostino, D.; Marino, C.; Minichiello, F. Earth-to-air heat exchanger for NZEB in Mediterranean climate. Renew. Energy 2016 , 99 , 553–563. [ Google Scholar ] [ CrossRef ]
• Khabbaz, M.; Benhamou, B.; Limam, K.; Hollmuller, P.; Hamdi, H.; Bennouna, A. Experimental and numerical study of an earth-to-air heat exchanger for air cooling in a residential building in hot semi-arid climate. Energy Build. 2016 , 125 , 109–121. [ Google Scholar ] [ CrossRef ]
• Menhoudj, S.; Mokhtari, A.-M.; Benzaama, M.-H.; Maalouf, C.; Lachi, M.; Makhlouf, M. Study of the energy performance of an earth—Air heat exchanger for refreshing buildings in Algeria. Energy Build. 2018 , 158 , 1602–1612. [ Google Scholar ] [ CrossRef ]
• Darkwa, J.; Kokogiannakis, G.; Magadzire, C.L.; Yuan, K. Theoretical and practical evaluation of an earth-tube (E-tube) ventilation system. Energy Build. 2011 , 43 , 728–736. [ Google Scholar ] [ CrossRef ]
• Iglesias, M.; Rodriguez, J.; Franco, D. Monitoring of Building Heating and Cooling Systems Based on Geothermal Heat Pump in Galicia (Spain). EPJ Web Conf. 2012 , 33 , 05004. [ Google Scholar ] [ CrossRef ]
• Noorollahi, Y.; Bigdelou, P.; Pourfayaz, F.; Yousefi, H. Numerical modeling and economic analysis of a ground source heat pump for supplying energy for a greenhouse in Alborz province, Iran. J. Clean. Prod. 2016 , 131 , 145–154. [ Google Scholar ] [ CrossRef ]
• Kelly, J.A.; Fu, M.; Clinch, J.P. Residential home heating: The potential for air source heat pump technologies as an alternative to solid and liquid fuels. Energy Policy 2016 , 98 , 431–442. [ Google Scholar ] [ CrossRef ]
• Garber-Slaght, R.; Peterson, R. Can Ground Source Heat Pumps Perform Well in Alaska? In Proceedings of the 2017 Proceedings of the IGSHPA Technical/Research Conference and Expo, Denver, CO, USA, 14–16 March 2017. [ Google Scholar ] [ CrossRef ]
• Liu, X.; Malhotra, M.; Walburger, A. Performance Analysis of Ground Source Heat Pump Demonstration Projects in the United States…|ORNL 2016. Available online: https://www.ornl.gov/publication/performance-analysis-ground-source-heat-pump-demonstration-projects-united-states (accessed on 5 April 2023).
• Gehlin, S.; Spitler, J.D.; Larsson, A.; Annsberg, Å. Measured performance of the University of Stockholm Studenthuset ground source heat pump system. In Proceedings of the 14th International Conference on Energy Storage, Adana, Turkey, 25–28 April 2018. [ Google Scholar ]
• Sivasakthivel, T.; Murugesan, K.; Sahoo, P.K. Potential Reduction in CO 2 Emission and Saving in Electricity by Ground Source Heat Pump System for Space Heating Applications-A Study on Northern Part of India. Procedia Eng. 2012 , 38 , 970–979. [ Google Scholar ] [ CrossRef ]
• Thiers, S.; Peuportier, B. Thermal and environmental assessment of a passive building equipped with an earth-to-air heat exchanger in France. Sol. Energy 2008 , 82 , 820–831. [ Google Scholar ] [ CrossRef ]
• Chen, C.; Sun, F.; Feng, L.; Liu, M. Underground water-source loop heat-pump air-conditioning system applied in a residential building in Beijing. Appl. Energy 2005 , 82 , 331–344. [ Google Scholar ] [ CrossRef ]
• Woodson, T.; Coulibaly, Y.; Traore, E.S. Earth Air Heat Exchangers for Passive Air Conditioning: Case Study Burkina Faso. Sud. Sci. Technol. 2009 , 17 , 54–64. [ Google Scholar ]
• Bansal, V.; Misra, R.; Agrawal, G.D.; Mathur, J. Performance evaluation and economic analysis of integrated earth–air–tunnel heat exchanger–evaporative cooling system. Energy Build. 2012 , 55 , 102–108. [ Google Scholar ] [ CrossRef ]
• Shukla, A.; Tiwari, G.N.; Sodha, M.S. Parametric and experimental study on thermal performance of an earth–air heat exchanger. Int. J. Energy Res. 2006 , 30 , 365–379. [ Google Scholar ] [ CrossRef ]
• Belatrache, D.; Bentouba, S.; Bourouis, M. Numerical analysis of earth air heat exchangers at operating conditions in arid climates. Int. J. Hydrogen Energy 2017 , 42 , 8898–8904. [ Google Scholar ] [ CrossRef ]
• Sanusi, A.N.Z.; Shao, L.; Ibrahim, N. Passive ground cooling system for low energy buildings in Malaysia (hot and humid climates). Renew. Energy 2013 , 49 , 193–196. [ Google Scholar ] [ CrossRef ]
• Xamán, J.; Hernández-López, I.; Alvarado-Juárez, R.; Hernández-Pérez, I.; Álvarez, G.; Chávez, Y. Pseudo transient numerical study of an earth-to-air heat exchanger for different climates of México. Energy Build. 2015 , 99 , 273–283. [ Google Scholar ] [ CrossRef ]
• Do, S.L.; Baltazar, J.-C.; Haberl, J. Potential cooling savings from a ground-coupled return-air duct system for residential buildings in hot and humid climates. Energy Build. 2015 , 103 , 206–215. [ Google Scholar ] [ CrossRef ]
• Lu, Q.; Narsilio, G.A.; Aditya, G.R.; Johnston, I.W. Economic analysis of vertical ground source heat pump systems in Melbourne. Energy 2017 , 125 , 107–117. [ Google Scholar ] [ CrossRef ]
• Hakkaki-Fard, A.; Eslami-Nejad, P.; Aidoun, Z.; Ouzzane, M. A techno-economic comparison of a direct expansion ground-source and an air-source heat pump system in Canadian cold climates. Energy 2015 , 87 , 49–59. [ Google Scholar ] [ CrossRef ]
• Pedinotti-Castelle, M.; Astudillo, M.F.; Pineau, P.-O.; Amor, B. Is the environmental opportunity of retrofitting the residential sector worth the life cycle cost? A consequential assessment of a typical house in Quebec. Renew. Sustain. Energy Rev. 2019 , 101 , 428–439. [ Google Scholar ] [ CrossRef ]
• Kegel, M.; Tamasauskas, J.; Sunye, R.; Langlois, A. Assessment of a Solar Assisted Air Source and a Solar Assisted Water Source Heat Pump System in a Canadian Household. Energy Procedia 2012 , 30 , 654–663. [ Google Scholar ] [ CrossRef ]
• Udovichenko, A.; Zhong, L. Techno-economic analysis of air-source heat pump (ASHP) technology for single-detached home heating applications in Canada. Sci. Technol. Built Environ. 2020 , 26 , 1352–1370. [ Google Scholar ] [ CrossRef ]
• Rad, F.M.; Fung, A.S.; Leong, W.H. Feasibility of combined solar thermal and ground source heat pump systems in cold climate, Canada. Energy Build. 2013 , 61 , 224–232. [ Google Scholar ] [ CrossRef ]
• Dû, M.; Dutil, Y.; Rousse, D.R.; Paradis, P.-L.; Groulx, D. Economic and Energy Analysis of Domestic Ground Source Heat Pump Systems in four Canadian Cities. J. Renew. Sustain. Energy 2015 , 7 , 053113. [ Google Scholar ] [ CrossRef ]
• Chae, H.; Nagano, K.; Katsura, T.; Sakata, Y.; Serageldin, A.A. Life cycle cost analysis of ground source heat pump system based on multilayer thermal response test. Energy Build. 2022 , 261 , 111427. [ Google Scholar ] [ CrossRef ]
• Zheng, X.; Li, H.-Q.; Yu, M.; Li, G.; Shang, Q.-M. Benefit analysis of air conditioning systems using multiple energy sources in public buildings. Appl. Therm. Eng. 2016 , 107 , 709–718. [ Google Scholar ] [ CrossRef ]
• Luo, L.; Lu, L.; Xu, R.; Chen, J.; Wang, Y.; Shen, X.; Luo, Q. Environmental and economic analysis of renewable heating and cooling technologies coupled with biomethane utilization: A case study in Chongqing. Sustain. Energy Technol. Assess. 2023 , 56 , 102992. [ Google Scholar ] [ CrossRef ]
• Dong, Z.; Boyi, Q.; Pengfei, L.; Zhoujian, A. Comprehensive evaluation and optimization of rural space heating modes in cold areas based on PMV-PPD. Energy Build. 2021 , 246 , 111120. [ Google Scholar ] [ CrossRef ]
• Liu, Z.; Yu, Z.; Yang, T.; Li, S.; El Mankibi, M.; Roccamena, L.; Qin, D. Experimental investigation of a vertical earth-to-air heat exchanger system. Energy Convers. Manag. 2019 , 183 , 241–251. [ Google Scholar ] [ CrossRef ]
• Yu, W.; Chen, X.; Qingsong, M.; Gao, W.; Wei, X. Modeling and assessing earth-air heat exchanger using the parametric performance design method. Energy Sources Part Recovery Util. Environ. Eff. 2022 , 44 , 7873–7894. [ Google Scholar ] [ CrossRef ]
• Ma, Y.; Li, Y.Y.; Ma, Y.C.; Hu, X.F.; Hu, G.H. The Energy, Environmental and Economic Benefits Analysis of Ground-Source Heat Pump in Wuhan Region of Summer Condition. Appl. Mech. Mater. 2013 , 253–255 , 701–704. [ Google Scholar ] [ CrossRef ]
• Lei, Y.; Tan, H.; Wang, L. Post-evaluation of a ground source heat pump system for residential space heating in Shanghai China. IOP Conf. Ser. Earth Environ. Sci. 2017 , 93 , 012053. [ Google Scholar ] [ CrossRef ]
• Hu, X.F.; Li, Y.Y.; Ma, Y.; Hu, G.H.; Tang, Q. Analysis of Energy and Environmental Benefits about Ground-Source Heat Pump under Heating Conditions in Wuhan Region. Adv. Mater. Res. 2013 , 608–609 , 974–978. [ Google Scholar ] [ CrossRef ]
• Macenić, M.; Kurevija, T.; Kapuralić, J. Heat pump system efficiency comparison of different renewable energy sources—A family house case study in Zagreb city area. Rud. Geolosko Naft. Zb. 2018 , 43 , 13–25. [ Google Scholar ] [ CrossRef ]
• Cardoza, Y.; Francia, G.; Martinez, L. Assessment of the Potential of Installing Space Cooling-Only Ground Source Heat Pumps in a Tropical Country. In Proceedings of the ASME 2011 5th International Conference on Energy Sustainability, Washington, DC, USA, 7–10 August 2011. [ Google Scholar ] [ CrossRef ]
• Rivoire, M.; Casasso, A.; Piga, B.; Sethi, R. Assessment of Energetic, Economic and Environmental Performance of Ground-Coupled Heat Pumps. Energies 2018 , 11 , 1941. [ Google Scholar ] [ CrossRef ]
• Saari, A.; Kalamees, T.; Jokisalo, J.; Michelsson, R.; Alanne, K.; Kurnitski, J. Financial viability of energy-efficiency measures in a new detached house design in Finland. Appl. Energy 2012 , 92 , 76–83. [ Google Scholar ] [ CrossRef ]
• Hamdy, M.; Mauro, G.M. Multi-Objective Optimization of Building Energy Design to Reconcile Collective and Private Perspectives: CO 2 -eq vs. Discounted Payback Time. Energies 2017 , 10 , 1016. [ Google Scholar ] [ CrossRef ]
• Paiho, S.; Pulakka, S.; Knuuti, A. Life-cycle cost analyses of heat pump concepts for Finnish new nearly zero energy residential buildings. Energy Build. 2017 , 150 , 396–402. [ Google Scholar ] [ CrossRef ]
• Blum, P.; Campillo, G.; Kölbel, T. Techno-economic and spatial analysis of vertical ground source heat pump systems in Germany. Energy 2011 , 36 , 3002–3011. [ Google Scholar ] [ CrossRef ]
• Badescu, V. Economic aspects of using ground thermal energy for passive house heating. Renew. Energy 2007 , 32 , 895–903. [ Google Scholar ] [ CrossRef ]
• Misra, A.K.; Gupta, M.; Lather, M.; Garg, H. Design and performance evaluation of low cost Earth to air heat exchanger model suitable for small buildings in arid and semi arid regions. KSCE J. Civ. Eng. 2015 , 19 , 853–856. [ Google Scholar ] [ CrossRef ]
• Biglarian, H.; Saidi, M.H.; Abbaspour, M. Economic and environmental assessment of a solar-assisted ground source heat pump system in a heating-dominated climate. Int. J. Environ. Sci. Technol. 2019 , 16 , 3091–3098. [ Google Scholar ] [ CrossRef ]
• Mostafaeipour, A.; Goudarzi, H.; Khanmohammadi, M.; Jahangiri, M.; Sedaghat, A.; Norouzianpour, H.; Chowdhury, S.; Techato, K.; Issakhov, A.; Almutairi, K.; et al. Techno-economic analysis and energy performance of a geothermal earth-to-air heat exchanger (EAHE) system in residential buildings: A case study. Energy Sci. Eng. 2021 , 9 , 1807–1825. [ Google Scholar ] [ CrossRef ]
• Farzanehkhameneh, P.; Soltani, M.; Moradi Kashkooli, F.; Ziabasharhagh, M. Optimization and energy-economic assessment of a geothermal heat pump system. Renew. Sustain. Energy Rev. 2020 , 133 , 110282. [ Google Scholar ] [ CrossRef ]
• Noorollahi, Y.; Ghasemi, G.; Kowsary, F.; Roumi, S.; Jalilinasrabady, S. Modelling of heat supply for natural gas pressure reduction station using geothermal energy. Int. J. Sustain. Energy 2019 , 38 , 773–793. [ Google Scholar ] [ CrossRef ]
• Yousefi, H.; Noorollahi, Y.; Abedi, S.; Panahian, K.; MirAbadi, A.H.; Abedi, S. Economic and Environmental Feasibility Study of Greenhouse Heating and Cooling using Geothermal Heat Pump in Northwest Iran. In Proceedings of the World Geothermal Congress, Melbourne, Australia, 31 January 2014. [ Google Scholar ]
• Yousefi, H.; Ármannsson, H.; Roumi, S.; Tabasi, S.; Mansoori, H.; Hosseinzadeh, M. Feasibility study and economical evaluations of geothermal heat pumps in Iran. Geothermics 2018 , 72 , 64–73. [ Google Scholar ] [ CrossRef ]
• Abu-Rumman, M.; Hamdan, M.; Ayadi, O. Performance enhancement of a photovoltaic thermal (PVT) and ground-source heat pump system. Geothermics 2020 , 85 , 101809. [ Google Scholar ] [ CrossRef ]
• Seo, Y.; Seo, U.-J.; Kim, J.-H. Economic feasibility of ground source heat pump system deployed in expressway service area. Geothermics 2018 , 76 , 220–230. [ Google Scholar ] [ CrossRef ]
• Gabrielli, L.; Bottarelli, M. Financial and economic analysis for ground-coupled heat pumps using shallow ground heat exchangers. Sustain. Cities Soc. 2016 , 20 , 71–80. [ Google Scholar ] [ CrossRef ]
• Risinggård, V.K.; Sivertsen, O.; Thisted, U.; MidttØmme, K. Performance study and life-cycle cost analysis of a ground-source heat-pump system in a commercial building in Norway. Sci. Technol. Built Environ. 2023 , 29 , 131–145. [ Google Scholar ] [ CrossRef ]
• Gradziuk, P.; Siudek, A.; Klepacka, A.M.; Florkowski, W.J.; Trocewicz, A.; Skorokhod, I. Heat Pump Installation in Public Buildings: Savings and Environmental Benefits in Underserved Rural Areas. Energies 2022 , 15 , 7903. [ Google Scholar ] [ CrossRef ]
• Gradziuk, P.; Gradziuk, B. Economic Efficiency of Applying a Heat Pump System in Heating Based on The Example of The Ruda-Huta Commune Experience. Rocz. Nauk. Stowarzyszenia Ekon. Rol. Agrobiznesu. 2019 , XXI , 88–96. [ Google Scholar ] [ CrossRef ]
• Nikitin, A.; Deymi-Dashtebayaz, M.; Muraveinikov, S.; Nikitina, V.; Nazeri, R.; Farahnak, M. Comparative study of air source and ground source heat pumps in 10 coldest Russian cities based on energy-exergy-economic-environmental analysis. J. Clean. Prod. 2021 , 321 , 128979. [ Google Scholar ] [ CrossRef ]
• Alshehri, F.; Beck, S.; Ingham, D.; Ma, L.; Pourkashanian, M. Techno-economic analysis of ground and air source heat pumps in hot dry climates. J. Build. Eng. 2019 , 26 , 100825. [ Google Scholar ] [ CrossRef ]
• Alshehri, F.; Beck, S.; Ingham, D.; Ma, L.; Pourkashanian, M. Technico-economic modelling of ground and air source heat pumps in a hot and dry climate. Proc. Inst. Mech. Eng. Part J. Power Energy 2021 , 235 , 1225–1239. [ Google Scholar ] [ CrossRef ]
• Yoon, S.; Lee, S.-R. Life cycle cost analysis and smart operation mode of ground source heat pump system. Smart Struct. Syst. 2015 , 16 , 743–758. [ Google Scholar ] [ CrossRef ]
• Sim, M.; Suh, D. A heuristic solution and multi-objective optimization model for life-cycle cost analysis of solar PV/GSHP system: A case study of campus residential building in Korea. Sustain. Energy Technol. Assess. 2021 , 47 , 101490. [ Google Scholar ] [ CrossRef ]
• Dinh, B.H.; Kim, Y.-S.; Yoon, S. Experimental and numerical studies on the performance of horizontal U-type and spiral-coil-type ground heat exchangers considering economic aspects. Renew. Energy 2022 , 186 , 505–516. [ Google Scholar ] [ CrossRef ]
• Ramos-Escudero, A.; García-Cascales, M.S.; Urchueguía, J.F. Evaluation of the Shallow Geothermal Potential for Heating and Cooling and Its Integration in the Socioeconomic Environment: A Case Study in the Region of Murcia, Spain. Energies 2021 , 14 , 5740. [ Google Scholar ] [ CrossRef ]
• Jalilzadehazhari, E.; Pardalis, G.; Vadiee, A. Profitability of Various Energy Supply Systems in Light of Their Different Energy Prices and Climate Conditions. Buildings 2020 , 10 , 100. [ Google Scholar ] [ CrossRef ]
• Kul, O.; Uğural, M.N. Comparative Economic and Experimental Assessment of Air Source Heat Pump and Gas-fired boiler: A Case Study from Turkey. Sustainability 2022 , 14 , 14298. [ Google Scholar ] [ CrossRef ]
• Seker, U.E.; Efe, S. Comparative economic analysis of air conditioning system with groundwater source heat pump in general-purpose buildings: A case study for Kayseri. Renew. Energy 2023 , 204 , 372–381. [ Google Scholar ] [ CrossRef ]
• Esen, H.; Inalli, M.; Esen, M. A techno-economic comparison of ground-coupled and air-coupled heat pump system for space cooling. Build. Environ. 2007 , 42 , 1955–1965. [ Google Scholar ] [ CrossRef ]
• Fernández, J.C.R. Integration capacity of geothermal energy in supermarkets through case analysis. Sustain. Energy Technol. Assess. 2019 , 34 , 49–55. [ Google Scholar ] [ CrossRef ]
• Ghaith, F.; Alsouda, F. Enhancing the performance of the building’s vapor compression air cooling system using earth-air heat exchanger. In Proceedings of the ASME 2017 11th International Conference on Energy Sustainability, Charlotte, NC, USA, 26–30 June 2017. [ Google Scholar ]
• Zhu, Y.; Tao, Y.; Rayegan, R. A comparison of deterministic and probabilistic life cycle cost analyses of ground source heat pump (GSHP) applications in hot and humid climate. Energy Build. 2012 , 55 , 312–321. [ Google Scholar ] [ CrossRef ]
• O’Neill, Z.D.; Spitler, J.D.; Rees, S. Performance analysis of standing column well ground heat exchanger systems. ASHRAE Trans. 2006 , 112 , 633–644. [ Google Scholar ]
• Bolling, A.; James, M. Investigation of Optimal Heating and Cooling Systems in Residential Buildings. ASHRAE Trans. 2008 , 114 , 128–139. [ Google Scholar ]
• Najib, A.; Zarrella, A.; Narayanan, V.; Bourne, R.; Harrington, C. Techno-economic parametric analysis of large diameter shallow ground heat exchanger in California climates. Energy Build. 2020 , 228 , 110444. [ Google Scholar ] [ CrossRef ]
• Honari, H.; Makhyoun, M.; Sridhar, V.; Hoover, K. Economic analysis of ground source heat pumps in North Carolina. ASHRAE Trans. 2014 , 120 , SE-14-C004. [ Google Scholar ]
• Kim, H.; Junghans, L. Integrative economic framework incorporating the Emission Trading Scheme (ETS) for U.S. Residential energy systems. Energy Convers. Manag. X 2022 , 14 , 100197. [ Google Scholar ] [ CrossRef ]

Share and Cite

Vanbaelinghem, L.; Costantino, A.; Grassauer, F.; Pelletier, N. Alternative Heating, Ventilation, and Air Conditioning (HVAC) System Considerations for Reducing Energy Use and Emissions in Egg Industries in Temperate and Continental Climates: A Systematic Review of Current Systems, Insights, and Future Directions. Sustainability 2024 , 16 , 4895. https://doi.org/10.3390/su16124895

Vanbaelinghem L, Costantino A, Grassauer F, Pelletier N. Alternative Heating, Ventilation, and Air Conditioning (HVAC) System Considerations for Reducing Energy Use and Emissions in Egg Industries in Temperate and Continental Climates: A Systematic Review of Current Systems, Insights, and Future Directions. Sustainability . 2024; 16(12):4895. https://doi.org/10.3390/su16124895

Vanbaelinghem, Leandra, Andrea Costantino, Florian Grassauer, and Nathan Pelletier. 2024. "Alternative Heating, Ventilation, and Air Conditioning (HVAC) System Considerations for Reducing Energy Use and Emissions in Egg Industries in Temperate and Continental Climates: A Systematic Review of Current Systems, Insights, and Future Directions" Sustainability 16, no. 12: 4895. https://doi.org/10.3390/su16124895

Article Metrics

Article access statistics, supplementary material.

ZIP-Document (ZIP, 333 KiB)

Further Information

Mdpi initiatives, follow mdpi.

Subscribe to receive issue release notifications and newsletters from MDPI journals

Search the United Nations

• What Is Climate Change
• Myth Busters
• Renewable Energy
• Finance & Justice
• Initiatives
• Sustainable Development Goals
• Paris Agreement
• Climate Ambition Summit 2023
• Climate Conferences
• Press Material
• Communications Tips

Causes and Effects of Climate Change

Fossil fuels – coal, oil and gas – are by far the largest contributor to global climate change, accounting for over 75 per cent of global greenhouse gas emissions and nearly 90 per cent of all carbon dioxide emissions.

As greenhouse gas emissions blanket the Earth, they trap the sun’s heat. This leads to global warming and climate change. The world is now warming faster than at any point in recorded history. Warmer temperatures over time are changing weather patterns and disrupting the usual balance of nature. This poses many risks to human beings and all other forms of life on Earth.

Causes of Climate Change

Generating power

Generating electricity and heat by burning fossil fuels causes a large chunk of global emissions. Most electricity is still generated by burning coal, oil, or gas, which produces carbon dioxide and nitrous oxide – powerful greenhouse gases that blanket the Earth and trap the sun’s heat. Globally, a bit more than a quarter of electricity comes from wind, solar and other renewable sources which, as opposed to fossil fuels, emit little to no greenhouse gases or pollutants into the air.

Manufacturing goods

Manufacturing and industry produce emissions, mostly from burning fossil fuels to produce energy for making things like cement, iron, steel, electronics, plastics, clothes, and other goods. Mining and other industrial processes also release gases, as does the construction industry. Machines used in the manufacturing process often run on coal, oil, or gas; and some materials, like plastics, are made from chemicals sourced from fossil fuels. The manufacturing industry is one of the largest contributors to greenhouse gas emissions worldwide.

Cutting down forests

Cutting down forests to create farms or pastures, or for other reasons, causes emissions, since trees, when they are cut, release the carbon they have been storing. Each year approximately 12 million hectares of forest are destroyed. Since forests absorb carbon dioxide, destroying them also limits nature’s ability to keep emissions out of the atmosphere. Deforestation, together with agriculture and other land use changes, is responsible for roughly a quarter of global greenhouse gas emissions.

Using transportation

Most cars, trucks, ships, and planes run on fossil fuels. That makes transportation a major contributor of greenhouse gases, especially carbon-dioxide emissions. Road vehicles account for the largest part, due to the combustion of petroleum-based products, like gasoline, in internal combustion engines. But emissions from ships and planes continue to grow. Transport accounts for nearly one quarter of global energy-related carbon-dioxide emissions. And trends point to a significant increase in energy use for transport over the coming years.

Producing food

Producing food causes emissions of carbon dioxide, methane, and other greenhouse gases in various ways, including through deforestation and clearing of land for agriculture and grazing, digestion by cows and sheep, the production and use of fertilizers and manure for growing crops, and the use of energy to run farm equipment or fishing boats, usually with fossil fuels. All this makes food production a major contributor to climate change. And greenhouse gas emissions also come from packaging and distributing food.

Powering buildings

Globally, residential and commercial buildings consume over half of all electricity. As they continue to draw on coal, oil, and natural gas for heating and cooling, they emit significant quantities of greenhouse gas emissions. Growing energy demand for heating and cooling, with rising air-conditioner ownership, as well as increased electricity consumption for lighting, appliances, and connected devices, has contributed to a rise in energy-related carbon-dioxide emissions from buildings in recent years.

Consuming too much

Your home and use of power, how you move around, what you eat and how much you throw away all contribute to greenhouse gas emissions. So does the consumption of goods such as clothing, electronics, and plastics. A large chunk of global greenhouse gas emissions are linked to private households. Our lifestyles have a profound impact on our planet. The wealthiest bear the greatest responsibility: the richest 1 per cent of the global population combined account for more greenhouse gas emissions than the poorest 50 per cent.

Based on various UN sources

Effects of Climate Change

Hotter temperatures

As greenhouse gas concentrations rise, so does the global surface temperature. The last decade, 2011-2020, is the warmest on record. Since the 1980s, each decade has been warmer than the previous one. Nearly all land areas are seeing more hot days and heat waves. Higher temperatures increase heat-related illnesses and make working outdoors more difficult. Wildfires start more easily and spread more rapidly when conditions are hotter. Temperatures in the Arctic have warmed at least twice as fast as the global average.

More severe storms

Destructive storms have become more intense and more frequent in many regions. As temperatures rise, more moisture evaporates, which exacerbates extreme rainfall and flooding, causing more destructive storms. The frequency and extent of tropical storms is also affected by the warming ocean. Cyclones, hurricanes, and typhoons feed on warm waters at the ocean surface. Such storms often destroy homes and communities, causing deaths and huge economic losses.

Increased drought

Climate change is changing water availability, making it scarcer in more regions. Global warming exacerbates water shortages in already water-stressed regions and is leading to an increased risk of agricultural droughts affecting crops, and ecological droughts increasing the vulnerability of ecosystems. Droughts can also stir destructive sand and dust storms that can move billions of tons of sand across continents. Deserts are expanding, reducing land for growing food. Many people now face the threat of not having enough water on a regular basis.

A warming, rising ocean

The ocean soaks up most of the heat from global warming. The rate at which the ocean is warming strongly increased over the past two decades, across all depths of the ocean. As the ocean warms, its volume increases since water expands as it gets warmer. Melting ice sheets also cause sea levels to rise, threatening coastal and island communities. In addition, the ocean absorbs carbon dioxide, keeping it from the atmosphere. But more carbon dioxide makes the ocean more acidic, which endangers marine life and coral reefs.

Loss of species

Climate change poses risks to the survival of species on land and in the ocean. These risks increase as temperatures climb. Exacerbated by climate change, the world is losing species at a rate 1,000 times greater than at any other time in recorded human history. One million species are at risk of becoming extinct within the next few decades. Forest fires, extreme weather, and invasive pests and diseases are among many threats related to climate change. Some species will be able to relocate and survive, but others will not.

Not enough food

Changes in the climate and increases in extreme weather events are among the reasons behind a global rise in hunger and poor nutrition. Fisheries, crops, and livestock may be destroyed or become less productive. With the ocean becoming more acidic, marine resources that feed billions of people are at risk. Changes in snow and ice cover in many Arctic regions have disrupted food supplies from herding, hunting, and fishing. Heat stress can diminish water and grasslands for grazing, causing declining crop yields and affecting livestock.

More health risks

Climate change is the single biggest health threat facing humanity. Climate impacts are already harming health, through air pollution, disease, extreme weather events, forced displacement, pressures on mental health, and increased hunger and poor nutrition in places where people cannot grow or find sufficient food. Every year, environmental factors take the lives of around 13 million people. Changing weather patterns are expanding diseases, and extreme weather events increase deaths and make it difficult for health care systems to keep up.

Poverty and displacement

Climate change increases the factors that put and keep people in poverty. Floods may sweep away urban slums, destroying homes and livelihoods. Heat can make it difficult to work in outdoor jobs. Water scarcity may affect crops. Over the past decade (2010–2019), weather-related events displaced an estimated 23.1 million people on average each year, leaving many more vulnerable to poverty. Most refugees come from countries that are most vulnerable and least ready to adapt to the impacts of climate change.

Learn more about...

• What is climate change?

Our climate 101 offers a quick take on the how and why of climate change.

What is “net zero”, why is it important, and is the world on track to reach it?

Initiatives for action

Read about global initiatives aimed at speeding up the pace of climate action.

Facts and figures

• Causes and effects
• Myth busters

Cutting emissions

• Explaining net zero
• High-level expert group on net zero
• Checklists for credibility of net-zero pledges
• Greenwashing
• What you can do

Clean energy

• Renewable energy – key to a safer future
• What is renewable energy
• Five ways to speed up the energy transition
• Why invest in renewable energy
• Clean energy stories
• A just transition

Adapting to climate change

• Climate adaptation
• Early warnings for all
• Youth voices

Financing climate action

• Finance and justice
• Loss and damage
• $100 billion commitment
• Why finance climate action
• Biodiversity
• Human Security

International cooperation

• What are Nationally Determined Contributions
• Acceleration Agenda
• Climate Ambition Summit
• Climate conferences (COPs)
• Youth Advisory Group
• Action initiatives
• Secretary-General’s speeches
• Press material
• Fact sheets
• Communications tips

Environment

Apple 2030 a plan as innovative as our products., a detailed approach. from design to disassembly..

Design our products with recycled and renewable materials. 1

Our Approach

Recycled and renewable materials often carry a lighter footprint than mined materials. By sourcing more recycled and renewable content, we can help to one day end our reliance on mining.

Our Progress

22% of the materials we shipped in Apple products came from recycled and renewable sources. 2

Source all manufacturing electricity from clean energy.

Most of our carbon footprint comes from the electricity used to manufacture our products. So our suppliers are transitioning to electricity generated from solar, wind, and other renewable sources.

Over 320 of our suppliers have already committed to using 100% renewable electricity by 2030. 3

Package and ship our products with less emissions.

We’re eliminating plastic from our packaging and making it more compact. 4 And we’re prioritizing low-carbon shipping methods such as ocean, rail, and electric vehicles.

More than 97% of our packaging is now fiber based. 5

Match 100% of our products’ energy use with clean electricity. 6

We’re investing in global renewable energy projects that help address the electricity our products use. And we’re making these products even more energy efficient.

We’re matching 100% of the expected electricity use for Apple Watch models by investing in projects like the IP Radian Solar project. 7

Maximize the materials we recover from recycled products.

We’re creating technologies, such as our disassembly robot Daisy, to recover critical materials so they can be recycled and reused. 8

In 2023, we recycled nearly 40,000 metric tons of electronic materials. 9

Our progress by the numbers.

We introduced our most significant product emissions reductions to date with the 2023 Apple Watch lineup. 10

Over 55% reduction in CO₂e emissions across our carbon footprint since 2015.

18.5M metric tons of CO₂e emissions avoided through our Supplier Clean Energy Program in 2023.

22% of materials shipped in our products came from recycled and renewable sources in 2023.

12.8M devices and accessories sent to new owners for reuse in 2023.

20% reduction in product transportation emissions compared to 2022.

The proof is in our products.

The same innovative thinking that goes into creating the products you love goes into our environmental initiatives. And as we design our products, we’re also using smarter chemistry to make sure they’re safer for everyone who assembles, uses, and recycles them.

MacBook Air 15‑inch (M3 chip)

MacBook Air is now halfway there.

Of all our products, MacBook Air leads the way in total recycled content. It’s made with 50% recycled materials, 11 including:

• 100% recycled cobalt in the battery 12 and MagSafe connector magnets.
• 100% recycled gold in the plating of multiple printed circuit boards.
• 100% recycled rare earth elements in all magnets.

Aluminum that goes around. And around. And around.

Moving toward low‑carbon shipping.

Apple Watch Series 9

A major step toward 2030.

Apple Watch is a milestone on our journey to 2030. 10 It shows that we can design, make, and ship great products with the planet in mind.

Apple Watch Series 9 is:

• designed with 30% recycled materials. 14
• made with 100% renewable electricity.
• shipped 50% or more without airplanes. 15

A best-case scenario.

Package and Ship

Good things come in small, 100% fiber‑based packages.

More recycled materials. From the outside in.

To reach our goal of making products with only recycled and renewable content, we’ve prioritized 15 materials — including cobalt, tungsten, and gold — based on their high environmental and social impacts. These 15 materials account for over 87% of the total mass of the products we ship.

In iPhone 15, we’re using:

• 100% recycled cobalt in the battery, a first for Apple. 12
• 100% recycled tungsten in the Taptic Engine, which creates your devices’ notification vibrations.
• 100% recycled gold in the wire of all cameras, the plating of multiple printed circuit boards, and the USB‑C connector.

Daisy gets the most out of your old iPhone.

A luxurious textile that’s lighter on the planet.

View all product innovations

Partnerships that do a world of good.

Doing right by the planet means doing right by the people who live on it — especially those most impacted by environmental risks. So we’re supporting partners and communities worldwide. Because we can achieve more together than we can alone.

Carbon removal. It’s in our nature.

As we continue to reduce our footprint, we’re also investing in high-quality, nature-based carbon removal projects to balance the emissions we can’t yet avoid.

Partnering with Goldman Sachs and Conservation International, we created a first-of-its-kind initiative called the Restore Fund. It aims to remove carbon emissions from the atmosphere by investing in projects that restore forests, wetlands, and grasslands — while offering a financial return. We expect to exceed our goal of removing 1 million metric tons of carbon dioxide from the air by 2025 from this first fund.

The Restore Fund has invested in three high-quality forestry managers. Our first project is in Paraguay through an investment in Arbaro Advisors. We’re supporting their efforts to develop sustainably certified working forests while creating opportunities for local communities. We’re also partnering with Symbiosis to help them grow native hardwood trees and restore biodiversity in Brazil’s Atlantic Forest. And with BTG Pactual Timberland Investment Group, we’re supporting their efforts to restore forests and protect natural ecosystems in Brazil.

In 2023, we announced an expansion of the Restore Fund with up to an additional $200 million committed to Climate Asset Management — a joint venture between HSBC and Pollination. And in 2024, we added another $80 million commitment from key manufacturing partners Taiwan Semiconductor Manufacturing Company and Murata Manufacturing.

Climate solutions that champion social change.

Communities of color are most impacted by environmental risks. And they’ve historically been denied the opportunity to be part of the solution.

As part of Apple’s Racial Equity and Justice Initiative (REJI), our Impact Accelerator program supports and champions Black-, Hispanic/Latinx-, and Indigenous-owned businesses at the cutting edge of green technology and clean energy.

In 2023, our third cohort featured 12 entrepreneurs committed to energy efficiency, water stewardship, and recycling innovation. And many of them focused on bringing clean energy and opportunities to underserved communities. By championing their growth, we can help dismantle systemic barriers and create change that promotes social and economic equity.

Learn more about Impact Accelerator

Conserving water like the earth depends on it.

Water is among the planet’s most precious resources. So to protect it, we’re going beyond our corporate footprint, across our supply chain, and into the communities and watersheds where we operate.

Our supply chain accounts for 99% of our total water footprint. Through our Clean Water Program, we help train our suppliers to better reuse and recycle water. Thanks to this partnership, our participating suppliers are now reusing and recycling water in their factories at an average rate of 42%, which reduces the amount of freshwater we withdraw by billions of gallons every year.

In addition, five of our data centers — in Prineville, Oregon; Reno, Nevada; Mesa, Arizona; Maiden, North Carolina; and Viborg, Denmark — as well as 20 of our supplier facilities, have achieved certification to the Alliance for Water Stewardship Standard for leading water management practices in their regions.

More renewable electricity. More readily available.

We’re actively working to democratize access to renewable electricity around the globe. Because clean energy benefits all of us, our communities, and the environment.

Our Power for Impact initiative gives local communities and organizations access to cost-effective energy while supporting their economic growth and championing social impact. Solar projects in 20 countries, including South Africa, the Democratic Republic of Congo, and the Philippines, help provide clean energy to the communities that need it most.

In 2018, we launched the China Clean Energy Fund to accelerate renewable progress in China. Together with our suppliers, we’ve invested in 1,000 megawatts of clean energy.

Additionally, through the RE100 initiative, we partner with the world’s most influential businesses that have committed to using 100% renewable electricity. And by forming groups like the Asia Clean Energy Coalition, we’re using our voice to support laws and policies that promote more renewable energy across Asia.

Help make Mother Nature proud.

There are many small actions you can take to make a big difference for the planet.

Trade in your device for credit. Or recycle it for free.

It’s good for you and the planet.

Learn more about Apple Trade In

Perform your own repairs with Apple parts, tools, and manuals.

Learn more about Self Service Repair

Charge your iPhone when your local grid is cleaner. 17

Learn more about Clean Energy Charging

View cleaner times to use electricity in your area. 18

Learn more about Grid Forecast

Designed with the earth in mind.

Learn more about the progress of your Apple devices with our product environmental reports.

iPhone 15 Pro and iPhone 15 Pro Max

iPhone 15 and iPhone 15 Plus

iPhone 14 and iPhone 14 Plus

iPhone SE (3rd generation)

iPad Pro 11-inch and 13-inch (M4)

iPad Air 11-inch and 13-inch (M2)

iPad (10th generation)

iPad mini (6th generation)

Apple Watch

Apple Watch Ultra 2 — Carbon Neutral

Apple Watch Series 9 — Carbon Neutral

Apple Watch Series 9

Apple Watch SE — Carbon Neutral

Apple Watch Bands — Carbon Neutral

MacBook Pro 16-inch (M3 Pro or M3 Max chip)

MacBook Pro 14-inch (M3, M3 Pro, or M3 Max chip)

MacBook Air 13-inch and 15-inch (M3 chip)

MacBook Air 13-inch (M2 chip)

Studio Display

Pro Display XDR

Apple Vision Pro

HomePod (2nd generation)

HomePod mini

Apple TV 4K (3rd generation)

Archived reports

iPhone 14 Pro Max

iPhone 14 Pro

iPhone 13 Pro Max

iPhone 13 Pro

iPhone 13 mini

iPhone SE (2nd generation)

iPhone 12 Pro Max

iPhone 12 Pro

iPhone 12 mini

iPhone 11 Pro Max

View (2019 PDF)

iPhone 11 Pro

iPhone X S Max

View (2018 PDF)

View (2017 PDF)

iPhone 8 Plus

View (2016 PDF)

iPhone 7 Plus

iPhone SE (1st generation)

iPhone 6s Plus

View (2015 PDF)

View (2014 PDF)

View (2013 PDF)

View (2012 PDF)

View (2010 PDF)

View (2009 PDF)

iPad Pro 12.9‑inch (6th generation)

iPad Pro 11‑inch (4th generation)

iPad Air (5th generation)

iPad (9th generation)

iPad Pro 12.9-inch (5th generation)

iPad Pro 11-inch (3rd generation)

iPad Air (4th generation)

iPad (8th generation)

iPad Pro 12.9-inch (4th generation)

View (2020 PDF)

iPad Pro 11-inch (2nd generation)

iPad (7th generation)

iPad mini (5th generation)

iPad Air (3rd generation)

iPad Pro 12.9-inch (3rd generation)

iPad Pro 11-inch (1st generation)

iPad (6th generation)

iPad Pro 12.9-inch (2nd generation)

iPad (5th generation)

iPad Pro 10.5-inch

iPad Pro 9.7-inch

iPad Pro 12.9-inch

iPad mini 4

iPad mini 3

iPad mini 2

iPad (4th generation)

iPad (3rd generation)

View (2011 PDF)

Apple Watch Ultra (GPS + Cellular)

Apple Watch Series 8

Apple Watch Series 7 (GPS + Cellular, GPS)

View (2021 PDF)

Apple Watch Series 6 (GPS + Cellular, GPS)

Apple Watch SE (GPS + Cellular, GPS)

Apple Watch Series 5 (GPS + Cellular, GPS)

Apple Watch Series 4 (GPS + Cellular)

Apple Watch Series 4 (GPS)

Apple Watch Series 3 (GPS + Cellular)

Apple Watch Series 3 (GPS)

Apple Watch Series 2

Apple Watch Series 1

View (September 2015 PDF)

View (April 2015 PDF)

MacBook Air 15-inch (M2 chip)

View (2023 PDF)

MacBook Pro 16-inch (M2 Pro or M2 Max chip)

MacBook Pro 14-inch (M2 Pro or M2 Max chip)

MacBook Pro 13-inch (M2 chip)

View (2022 PDF)

MacBook Pro 16-inch

View (October 2021 PDF)

MacBook Pro 14-inch

MacBook Pro 13-inch

View (November 2020 PDF)

MacBook Air 13-inch (M1 chip)

MacBook Air 13-inch with Retina display

View (March 2020 PDF)

MacBook Pro 13-inch with Thunderbolt 3

View (May 2020 PDF)

View (July 2019 PDF)

MacBook Pro 15-inch with Thunderbolt 3

View (May 2019 PDF)

MacBook Air 13-inch

View (June 2017 PDF)

MacBook Pro 13-inch with Thunderbolt

MacBook Pro 15-inch with Thunderbolt

MacBook Pro 13-inch with Retina display

MacBook Pro 15-inch with Retina display

MacBook Air 11-inch

11-inch MacBook Air

13-inch MacBook Air

13-inch MacBook Pro

15-inch MacBook Pro

View (October 2011 PDF)

17-inch MacBook Pro

View (February 2011 PDF)

24-inch iMac

27-inch iMac with Retina 5K

21.5-inch iMac

21.5-inch iMac with Retina 4K

27-inch iMac with Retina 5K display

27-inch iMac

Mac mini with OS X Server

Mac mini with Lion Server

Mac mini with Snow Leopard Server

Apple Thunderbolt Display

27-inch Apple LED Cinema Display

24-inch Apple LED Cinema Display

View (2008 PDF)

View (January 2018 PDF)

Apple TV 4K (2nd generation)

Apple TV HD

Apple TV 4K

Apple TV (4th generation)

Apple TV (3rd generation)

iPod shuffle

iPod touch 32GB/64GB

iPod touch 16GB

iPod classic

View previous reports

An even closer look at our progress.

Learn more about our latest efforts to fight climate change and support equity.

2023 Progress Report

2022 Progress Report

2021 Progress Report

2020 Progress Report

2019 Progress Report

2018 Progress Report

2017 Progress Report

2016 Progress Report

2015 Progress Report

2014 Progress Report

2013 Progress Report

2012 Progress Report

2011 Progress Report

2010 Progress Report

2009 Progress Report

2008 Progress Report

Additional Reports and Resources

Circular economy.

Our aim is to make products using only recycled or renewable materials — so we prioritize, responsibly source, and recover materials.

• Learn how we prioritize materials with our Material Impact Profiles (PDF)
• Read our white paper on Apple’s Paper and Packaging Strategy (PDF)
• Read our Responsible Fiber Specification (PDF)
• Read our white paper on expanding access to service and repairs (PDF)
• Learn how to trade in or recycle your device
• Learn more about disassembly for professional recyclers

Smarter Chemistry

Apple has a rigorous program to ensure the safety of chemicals used in our products. Learn about Apple’s strict standards, detailed toxicological assessments, and methodology for assessing chemicals of concern.

• Read the Regulated Substances Specification (PDF)
• Read our white paper on Integrating Toxicological Assessments in Material Selection for Apple Products (PDF)
• Read our Protocol for Prioritizing Chemicals of Concern in the Electronics Industry (PDF)
• Read about Apple’s commitment to phasing out per- and polyfluoroalkyl substances (PFAS) (PDF)

Climate Change

Climate change is a defining issue of our time. View detailed updates on our progress.

• Read Apple’s 2023 CDP Climate Change response (PDF)
• Read our white paper on Apple’s Carbon Removal Strategy (PDF)

People and Environment in Our Supply Chain

We hold ourselves and our suppliers to the highest standards of labor and human rights, health and safety in the workplace, environmental practices, and the responsible sourcing of materials.

Visit the Supply Chain Innovation site

Frequently Asked Questions

Find answers to common questions about Apple and the environment.

Read the FAQs

More from Apple on the environment.

Our values lead the way., accessibility.

Our built-in accessibility features are designed to work the way you do.

We design every product and service to keep your data safe and secure.

Racial Equity and Justice Initiative

We’re addressing systemic racism by expanding opportunities for communities of color globally.

Supply Chain Innovation

We prioritize providing safe, respectful, supportive workplaces for everyone.

Inclusion and Diversity

We’re holding ourselves accountable for creating a culture where everyone belongs.

We empower students and educators to learn, create, and define their own success.

• Server: PR07  
• Printable Version
• Funding Opportunity
• Teaming Partner List
• Funding Archive
• Questions and Answers
• User Guides

Clean Energy Infrastructure Funding Opportunity Announcements

FOA Number   FOA Title   Announcement Type   Office   LOI Deadline   CP Deadline   FA Deadline   Loading… June 2024 Sun Mon Tue Wed Thu Fri Sat 22 26 27 28 29 30 31 1 23 2 3 4 5 6 7 8 24 9 10 11 12 13 14 15 25 16 17 18 19 20 21 22 26 23 24 25 26 27 28 29 27 30 1 2 3 4 5 6 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec DE-FO2-0003126: Wholesale Electricity Market Studies and Engagements The U.S. Department of Energy (DOE) is issuing, on behalf of the Grid Deployment Office (GDO), this Funding Opportunity Announcement (FOA). Awards made under this FOA will be funded, in whole or in part, with funds authorized under the Consolidated Appropriations Act, 2023 (Public Law 117-328). Creating more efficient and flexible wholesale markets that will support a more resilient and reliable grid will be critical as new load and generation come online. Functioning wholesale markets provide a platform for energy trading and the integration of electric resources into the grid. Efficient, fair, and transparent market constructs are thus foundational to transitioning to a clean, reliable, equitable electric grid. This FOA will assist applicants—States, ISOs/RTOs, and domestic entities that have partnered with States and/or ISOs/RTOs — that have formed partnerships with or otherwise include States, ISOs/RTOs to perform analytical studies on critical market issues or convene stakeholders to address issues facing developing or existing wholesale markets. GDO suggests five (5) broad priorities for proposed projects: 1) seams between markets, 2) regional resource adequacy, 3) market design and price formation, 4) regional footprint studies, and 5) integrated regional planning approaches. Please see the full FOA document in the Documents section below. Questions regarding the FOA must be submitted to [email protected]. The required Concept Paper due date for this FOA is 06/13/2024 at 5PM ET. The Full Application due date for this FOA is 08/22/2024 at 5PM ET. In the event that an Applicant experiences technical difficulties with a submission, the Applicant should contact the eXCHANGE helpdesk for assistance ([email protected]). Application Forms and Templates The following forms and templates may be used as part of the application submission. Note that these forms and templates do not necessarily constitute all the documents required for a complete application. Please refer to the 'Application and Submission Information' of the published announcement to learn more about the required application content requirements. Full Application Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. View all journals Explore content About the journal Publish with us Sign up for alerts Perspective Open access Published: 28 May 2024 Alternative protein sources: science powered startups to fuel food innovation Elena Lurie-Luke 1   Nature Communications volume  15 , Article number:  4425 ( 2024 ) Cite this article 2434 Accesses 24 Altmetric Metrics details Agriculture Tissue engineering Harnessing the potential of considerable food security efforts requires the ability to translate them into commercial applications. This is particularly true for alternative protein sources and startups being on the forefront of innovation represent the latest advancements in this field. Similar content being viewed by others The microbial food revolution Edible mycelium bioengineered for enhanced nutritional value and sensory appeal using a modular synthetic biology toolkit From sustainable feedstocks to microbial foods Introduction. In 2022 almost 735 million people, 9.2% of the global population, were undernourished 1 and as we are entering the second quarter of this century, the world faces a formidable task of feeding a growing population projected to reach 10 billion by 2050 2 . It is further aggravated by substantial food losses due to climate change and crop diseases 3 . To address this task requires a 50% increase in global food production in the next 25 years 2 and the significance of food innovation becoming increasingly evident in order to create solutions tackling the urgency and scale of this food security challenge. The World Resources Report ‘Creating a Sustainable Food Future’ 4 identified 22 solutions to address this need, which were grouped into five categories: (1) reduction of growth in demand for food and other agricultural products; (2) increase in food production without expanding agricultural land; (3) protection and restoration of natural ecosystems; (4) increase in fish supply; and (5) reduction of greenhouse gasses emissions from agricultural production. To implement these solutions, supporting the sustainable development goals 4 and also addressing the food security challenge, require new technologies and product innovations, i.e., it is essential to find innovative ways to produce and distribute food more efficiently and sustainably. Achieving this goal can involve developing novel farming techniques (precision agriculture), exploring alternative protein sources, or implementing smart technologies to reduce waste and optimise food supply chains. Considerable efforts have been put in place to address this challenge ranging from precision agriculture to food innovation (Fig.  1 ). This involves truly cross disciplinary innovation efforts for example, genetic modifications to increase crops’ resilience 5 , different antibacterial strategies to improve food security 6 , sensors 7 and big data advances for precision farming 8 , artificial intelligence (AI) and block chain technologies to manage food supply 9 , advancement in material science to develop functional packaging materials 10 , tissue engineering in the development of alternative protein sources 11 etc. Multidisciplinary approaches are required to effectively address the Food Security Challenge which result in innovation technologies and approaches, e.g., advancement in genetic engineering to develop high-yield and disease resistant crops; using drones and big data analytics for precision farming; expanding use of 3D bioprinting to produce non-animal based meat alternatives. Note: the diagram aims to provide an overview of innovation examples across different scientific areas rather to list all scientific fields involved in the Food Security area . However, harnessing the potential of such technologies for food security requires the ability to translate them into commercial and scalable applications. In many cases, the first step of this translation is done by startups and/or university spins outs. This is particularly true for the development of alternative protein sources, which has been selected as a topic for this review. Alternative protein sources are used to substitute animal source protein-rich foods and form an integral part of sustainable food systems to meet protein demands that are projected to nearly double by 2050 12 . Two opposing protein transition trends are taking place: low-income populations shift from plant to animal protein sources while high income populations are looking to substitute animal protein sources 13 . Multiple factors are driving this transition including economic growth in lower income countries and having more animal products in their diet 13 , while the raising environmental and health concerns have led to dietary changes in higher income countries 13 . However, it is important to note that these are not conflicting trends, i.e., it is possible to reduce the consumption of meat in high income countries and at the same time increase animal-based protein consumption among the socio-demographic groups for which more protein in their diet would be beneficial 14 . The current review aims to bring together the latest advancements in the alternative protein sources research and insights into their translation into product applications, i.e., their impact outcomes to address the food security challenge. Startups eco-system Data source. Startups, which are positioned at the forefront of technological innovation and aim to turn groundbreaking research into product applications and creating new solutions, present a good indicator of the latest technology and research advancements and as such were used as a data source for this review. Due to their agile and lean structure, they can rapidly pivot and iterate to drive technological progress that in many cases are further strengthened by their collaborations and partnerships with academia, established companies and other organisations. Eco-system design Most of reviews dedicated to the development of alternative food sources are structured around the production method 15 , 16 , 17 , 18 , e.g. cell-cultured products, precision fermentation, insect proteins etc and/or a specific source of alternative proteins 19 , 20 , 21 , 22 . The current eco-system was designed based on an innovation strategy to address a problem – finding an alternative to animal/fish-based proteins. When it comes to finding an alternative, there are three main options to consider: (1) using a replacement, (2) modifying existing non-animal/non-fish sources of proteins, and (3) making an alternative source of proteins (Fig. 2 ). Replace: this option involves using a readily available substitute for the target compound, e.g., current vegetarian diet options. Modify: this option looks in modifying existing non-animal/non-fish sources of proteins to substitute the target compound, e.g., insect-based protein. Make: This option comes from a product innovation standpoint, providing the most potential, while holding the biggest challenges. It includes using novel technological processes to make proteins, e.g. 3D bioprinting, cell-cultured products, precision fermentation etc. A problem-solving innovation strategy approach was used to design the startups eco-system. The problem to solve is to find an alternative to animal/fish-based proteins and when it comes to finding an alternative, there are three main options to consider: (1) using a replacement, (2) modifying existing non-animal/non-fish sources of proteins, and (3) making an alternative source of proteins. (1) Replace: this option involves using a readily available substitute for the target compound, e.g., current vegetarian diet options. (2) Modify: this option looks at modifying existing non-animal/non-fish sources of proteins to substitute the target compound, e.g., insect-based protein. (3) Make: This option comes from a product innovation standpoint, providing the most potential, while holding the biggest challenges. It includes using novel technological processes to make proteins, e.g. 3D bioprinting, cell-cultured products, precision fermentation etc. In terms of the market penetration, scalability and cost were main differentiating parameters between these three options (Fig.  3 ). Assuming the same consumer perception of different alternative proteins products, their market penetration would primarily depend on their scalability (ability to move from niche to mass market without compromising quality) and cost (at least parity to the animal/fish-based protein products). These two parameters were used to map market the penetration potential of different alternative protein options using current market examples. Note: products examples are intended to illustrate a relative position and presented in a non-scale format. Eco-system composition For illustrative purposes, 33 startups have been selected to provide a representative sample of the alternative protein startups eco-system (Table  1 ). The selection process was based on (i) sources of alternative proteins: insects, plant and cells; (ii) technology approach used e.g., extrusion, precision fermentation, 3D bioprinting, cell culture and (iii) the a type of alternative product, e.g. alternative meat, fish, chicken, protein, milk etc. The startups selection was rendered based on them (i) having an alternative protein product offering; (ii) representing some of the main trends and (iii) being active, i.e. website news posting in 2023. (Fig.  4 ). Startups eco-system is designed based on innovation strategy approach used to produce alternative proteins that forms three main pillars of the eco-system: (1) Replace, (2) Modify and (3) Make. Each pillar has 2–3 levels with one-to-two levels specific to each pillar. The specific levels were designed to represent specific features of each pillar, e.g. the first level in the make pillar is the type of manufacturing method/technology approach used to make alternative proteins while in the replacement pillar, it is based on different sources of the alternative proteins (insects, plants, fungi). The second level deals with product’s types, e.g. chicken, beef, salmon, snacks. The last level provides examples of startups selected based on them (i) having an alternative protein product offering; (ii) representing some of the main trends and (iii) being active, i.e. website news posting in 2023 and presented for illustrative purposes only. These companies have been reviewed across three main vectors: (1) scientific insight behind the technology; (2) product development stage and (3) key challenges. Alternative protein sources Replace (meat protein replacement). This option deals with using existing non-animal-derived ingredients to substitute proteins from animals and fish. While from a product innovation standpoint, it may not be considered significantly innovative, the process of considering replacement options utilises the latest developments in computer – digital databases and machine learning. A significant amount of data including food composition, nutritional composition and recipes is publicly available 23 , 24 , 25 . It provides a fruitful ground to utilise machine and deep learning approaches for food design 26 . Taking this approach, Eatkind Technologies Private Limited (India) has developed an AI-based tool (EatKind 27 ) to replace meat, egg and dairy ingredients in a recipe for a plant-based one. The EatKind site turns any recipe into a plant-based one by posting it in the site’s search box. Modify (non-meat source of proteins) The next option is using existing sources of proteins, such as insects and plants, as non-animal or/and fish protein s sources. Insect based Entomophagy, the consumption of insects as food, has been a common practice in many cultures for centuries 28 . Insects have great potential as a sustainable animal protein source due to their low impact on resources, e.g. emitting less greenhouse gases, requiring less water and space 29 . The data from various comparative analyses 30 , 31 , 32 of the protein and other nutrients content in edible insects and animal-derived meat have demonstrated that both edible insects and animal-derived meat have varied nutritional content with more profound variations in edible insects 30 . The latter was considered to be due to the diversity of individual species 32 . Edible insects have a higher protein content than animal meat 31 , ranging from 23.1 g to 35.2 g per 100 g among edible insect species and 19.2 g to 21.5 per 100 g in different types of meat 31 . In regard to the nutrition value, it seems that it is not possible to explicitly state that edible insects would have a higher nutritional value than animal-derived meat, because of the differences in the content of individual nutrients in edible insects and animal-derived meat 30 , 31 . In addition to this, this analysis would be impacted by using different nutrient profiling models 30 . An estimated 2 billion people 33 across Africa, Asia, Central and South America, and Australia consume insects and there is an increased interest in Western countries in insects as a potential source of food. The Edible Insects Market size is estimated at USD 3.20 billion in 2023, and is expected to reach USD 7.60 billion by 2028, growing at a compound annual growth rate of 18.89% in 2023-2028 34 . Two main factors contribute to this trend: (1) the growing acceptance of insect-based food in Western societies 35 and (2) their lower environmental impact to address the food security challenge. This rapid growth is supported by increasing investments. While the edible insects’ market is highly fragmented 34 , it has attracted more than USD 1.3 billion in funding to date with more than half of it in the past couple of years 36 . Increasing investment in the startups’ research and development (R&D) also comes from partnerships with existing companies. For example, Protirax announced a strategic partnership with Tyson Foods, one of the world’s largest food companies 37 , Ÿnsect launched a dog feed brand in the US in collaboration with Pure Ultra Simple LLS, a dog food start-up (US) 38 . To help scale up the edible insect-based business globally, many government organisations are developing programmes and initiatives including a collaboration between the Australian Centre for International Agricultural Research (ACIAR), AgriFutures Australia and the International Centre for Insect Physiology and Ecology (ICIPE) resulting in the creation of the Emerging Insect Technology Hub (EIT-Hub) that aims to bring together industry stakeholders, scientists and investors to discuss issues linked to emerging insect technologies around insects as food, animal feed and fertiliser 39 . The other example is the ‘Insectrial Revolution’ project which received USD 7.5 million from the UK government’s Industrial Strategy Challenge Fund (ISCF). This project focusses on the construction of the country’s first large-scale industrial insect farm run on food waste. It is being led by led by the insect-farming company Entocycle (UK) and brings together a consortium of 15 partners providing their diverse expertise and ranging from academic partners and multinational companies, e.g. insects technology expertise (BetaBugs, Better Origin, Fera); science (Durham University, University of Stirling, University of Warwick, Scottish Aquaculture Innovation Centre); waste management (not-for-profit environmental organisation Zero Waste Scotland) and a multinational company (Tesco) 40 . Following the development of relevant regulatory frameworks and legislations covering edible insects, the companies (examples are given in Table  1 ) were able to place their product in the market, making them available to consumers. For example, in the United States, edible insects and insect-based food products must comply with the Federal Food, Drug, and Cosmetic Act (FD&C Act) 41 , in the European Union all insect-based products (whole insects, their parts or extracts) meant for human consumption have fallen under the novel food regulation EU 2015/2283 41 and in the United Kingdom the Food Standards Agency (FSA) is now requiring insect companies to submit dossiers of evidence of safety 42 . Insect-based food startups’ activities range from harvesting the insects to producing food products (examples are given in Table  1 ). These companies’ development is a result of a multi-disciplinary effort encompassing entomology (various rearing techniques), together with food and nutritional science (product formulation and processing methods). For example, Ÿnsect 43 , a French startup, has the largest vertical farm in the world and its recent innovation is a genotyping chip Axiom® YNS_Mol1 for insect breeding aid selection of larvae lines to produce insect-based proteins. This chip has been made available for companies and the scientific community. Big data genome analytics, RNAi and CRISPR are used by Beta 44  to customise their insects 44 . Other startups are working to integrate insect powders into the Western world diet by developing products palatable to the Western taste preferences, e.g., protein bars, chocolates, and beetle-based meats by Hey Planet 45 and/or YumBug 46 opening an insect food-based restaurant. The farming of insects for feed and the production of insect-based foods are relatively recent and bring both benefits and challenges. As with other foods, potential food hazards 41 , 42 of insects-based food could include biological agents (bacterial, viral, fungal, parasitic), chemical contaminants (pesticides, toxic metals, flame retardants), potential allergic reaction, in particular in individuals with crustaceans’ allergies to allergen cross-reactivity. The high nutritional content and the low carbon, water and ecological footprints associated with insect production, as compared to those of other livestock species, make them an attractive protein replacement option for a healthy diet both for animals and humans. However, further studies and monitoring will be required to determine their quality and safety 41 . From the companies’ perspectives more efforts will be required to increase broader consumers’ acceptability of insect-based food and address the current key barriers dealing with neophobia and repulsion (the yuck factor) with insect food 47 . The main focus areas to address these barriers include information dissemination about benefits and how to incorporate the insect-based food and improving sensorial experience by developing appealing products. Plant based Humans have consumed plant-based protein food since ancient times. Records of using soybean in ancient kitchens to produce soybean milk as well as preparing tofu from coagulated soybean milk go back to the Han Dynasty in China 48 . Advancements in processing technology 19 , in particular, sheer cell, extrusion, structuring processes aiming to develop a fibrous structure, the development textured vegetable proteins, as well as ability to address environmental and food security challenges, have resulted in a significant increase in the consumption of plant-based foods. These methods also enable better mimicking of animal source foods by plant-based meat analogues/alternatives (PBMA) and plant-based dairy analogues/alternatives (PBDA). Currently, there are more than one thousand companies operating in this space with 40% of them focussing on PBMAs and PBDAs food production 49 . Over the last decade there has been a rapid rise in the number of PBMA and PBDA startups with 80% of the current companies in this sector being established during this period 49 . The same trend is also observed across different players ranging from academia research to large food companies. It is becoming a subject of numerous articles and review papers 19 that look at different aspects of producing PBMA and PBDA food including technological developments, life cycle impact assessments to evaluate the sustainability of plant-based meat products, the health benefits, consumers’ perceptions etc. Large food companies recognise the importance of alternative proteins and are increasing their investment as well launching plant-based version of their popular products including dairy-free Philadelphia cream cheese by Kraft Heinz and Mondelez International, Kellogg’s plant-based chicken waffle Eggo sandwich and Burger King’s Impossible burgers 50 . The presence of large food companies has a profound effect on the plant-based alternative market and is driving its consolidation, e.g. The Kellogg Company, Maple Leaf Foods and Conagra Brands taking nearly 70% of the plant-based meat sales in the US with the Kellogg Company accounting for almost 50% of the total sales 51 . Plant-based meat, seafood, eggs, and dairy companies attracted USD 1.2 billion investment in 2022 and the number of unique investors in plant-based companies grew by 17 percent and reached more than 1500 investors 50 . Similarly, to the edible insect category, the plant-based meat alternatives receive significant support from the public sector, e.g. the German government’s promise to invest USD 41 million in plant-based foods and alternative proteins 52 . Denmark, Sweden, and Switzerland committed to invest more than USD 150 million into plant-based protein R&D 50 . The newest versions of PBMA have similar textures, comparable smells, and appearance to help mimic animal meat. The Spanish startup, Novameat 53 uses 3D bioprinting to create fibres and microfibres that unlock the texture of meat and provide versatility to develop a range of PBMA products. To solve the texture challenge, the Israeli startup MeatTheEnd 54 has developed a proprietary technique to incorporate a unique pre-treatment step prior to extrusion to produce texturized protein ingredients. In combination with extrusion technology that is used in mass-scale production, this method results in a cost-effective solution for PBMA companies that seeks to improve the texture of their products. Lypid (US) is looking to address the sensorial and nutritional challenges of PBMA by providing plant-based fats. It uses encapsulation technique to produce emulsion of plant oils (‘alternative fat’) that behaves like animal fat 55 . Another source of alternative proteins are fungi that includes microorganisms such as yeasts and moulds with mushrooms being the most familiar form. A number of startup companies use filamentous fungi as a source of microproteins. For example, Revo Foods (Austria) has developed a proprietary extrusion process and fibrous protein matrix from filamentous fungi to produce 3D-printed salmon-like fillet on a commercial scale 56 while Mycorena (Sweden) is using a liquid fermentation process to produce fungi-based protein food ingredient and also fungi-stabilised fat that can be used to improve the sensorial performance of PBMA products 57 . A cross-sectional analysis 58 of more than 200 products in each product category, PBM and meat, demonstrated that PBM products had significantly lower protein content than meat products, for example, mean protein content per 100 g in meat sausages was 15 g and 12.1 g in PBM sausages; in meat burgers 19.9 g in PBM burgers and 23.3 g in plain chicken and 18.7 g in plant-based chicken. However, according to the UK’s Nutritional Profiling Model, more PBM products were classified as healthier than meat products, i.e. 14% of PBM and 40% of meat products were classified as ‘less healthy’ ( p  < 0.001) 58 . Future studies are needed to better understand how the presence and absence of metabolites and nutrients in plant-based meat alternatives and meat impacts short- and long-term consumer health. Technological advances have enabled the field to address a range of critical issues; however, there are still a number of challenges including scalability and cost that remain. The main challenges around PBMAs include allergy concerns associated with soy and wheat; requiring additional flavouring ingredients to achieve the meaty flavour; ability to incorporate fat into the product and potentially a higher risk than meat products of microbial growth due to high-moisture environments with a neutral pH 59 . In terms of PBDAs, they have some performance issues dealing with stability and removal of off flavours, e.g. a beany flavour, bitter taste, and astringency. In addition to the above, there is limited scientific data related to the safety of PBMAs and PBDAs. Make (made/produced protein sources: lab grown meat) Creating a meat substitute is perhaps the most challenging option as it involves the production of meat in vitro. The foresight of growing meat outside an animal environment in 1931 when in his speech ‘Fifty Years Hence’, Winston Churchill said ‘We shall escape the absurdity of growing a whole chicken in order to eat the breast or wing, by growing these parts separately under a suitable medium.’ 60 The latest progress in cross disciplinary efforts including tissue engineering, stem cell biology, bioprocess engineering has made this feat possible. There are currently more than 150 companies 20 working to produce lab grown meat, which typically follow one of the following technologies routes: (1) processing cell cultures grown in bioreactors; (2) 3D-bioprinting or (3) precision fermentation (Fig.  4 ). Processed cell cultures Harrison’s pioneering work 20 in 1907 led to the development of the cell culture techniques. The progress made in more than 100 years of research in this field resulted into it becoming a widely used research tool 21 as well as a wide range of biotechnology applications including the tissue engineering, regeneration medicine, cells for vaccine and cell therapy. ‘Cultured meat’ presents one of the latest developments in the field of cell culture. The approach relies on growing and expanding animal stem cells inside a bioreactor and then using them to produce cultivated meat. In the early 2000s the first world’s research institute dedicated to cultured animal products was formed and it took just over 20 years from a cultured meat concept to a cultured meat product on the market. In recent years there has been a considerable rise of cultured meat startups with 156 companies operating in this space by in 2022 and USD 2.8 billion all-time investment in cultivated meat and seafood companies 12 . Their products range from common meat such as chicken (Upside Food 61 (US), GoodMeat/Eat Just 62 (US)), beef (Aleph Farms 63 (Israel)), pork (Meatable 64 (Netherlands)) to seafood (Wildtype 65 (US), Avant Meat 66 (China) and high-end food including foie gras (Gourmey 67 (France)). In the 2016-2022 period, the cultivated meat and seafood companies attracted USD 2.78 billion 12 . The funding streams include unique investors reaching 679 investors 12 , strategic partnerships between cultivated meat companies and major food companies with at least 35 major partnerships 12 including established companies like Nestlé, Merck KGaA, Mitsubishi, JBS, Kerry, and CP Kelco 12 and public funding. For example, Singapore’s government launched a number of programmes to support alternative protein startups and accelerate innovation including building the world’s first hybrid innovation centre dedicated to cultivated and plant-based meat products 68 . The development and manufacturing of alternative proteins, including cultivated meat, is a part of the UK Government £2 billion National Vision for Engineering Biology plan 69 . Cultured meat is still not widely available, and a number of hurdles 22 need to be overcome before it will become a product that is readily available to the masses. These challenges include the lack of regulatory guidelines: regulatory approvals are required to sell a product and many countries do not have established protocols for certifying cultured meat. The startups are navigating the current regulatory landscape, e.g., Singapore was the first country that approved cultivated chicken for public sale in 2020 70 , since then two startups, Upside Foods and Eat Just, received FDA’s approval 61 , 62 for their lab-grown chicken. Aleph Farms is seeking regulatory approval to sell its beefsteak in the UK and Switzerland 63 . To help facilitate the development of regulatory protocols, more understanding would be required to assess potential risks of microbial contamination, genetically engineered starting materials etc to address any food safety concerns. The other challenges include sensorial and visual acceptance and cost. For example, to develop a satisfying prototype version that could match the delicate flavour and creamy texture of foie gras, Gourmey tested 600 to 650 different compound interactions. Its product will be marketed as a “poultry delicacy as it cannot be called foie gras” in France. Wildtype is another startup that successfully managed the sensorial challenge and created sushi-grade salmon by cultivating cells extracted from salmon eggs and it has been reported that the resulting tastes like conventional sushi-grade salmon 65 . However, it comes at a cost - the 127 g (4.5 ounce) portion cost about USD 150 in food costs alone (USD 533 per 450 g (1 pound)). Limited information is available about the protein content in cultured meat 22 and according to morphological observations, there are indications that the current cultured meat with most of the cytoskeletal proteins is in the same range as traditional meat 71 . The cost represents another challenge of cultivated meat, which will decrease as technology improves to enable scale up. There is already evidence on making scalable beef cell lines using CRISPR by SciFi Foods 72 , a US based cultivated meat startup, which aims to eventually reach USD $1 per burger at a commercial scale. SCiFi noted that their technology allowed the cost reduction of cultivated meat by more than 1000 times compared to current production costs and less than USD 10 cost for its blended burger, part plant-based and part cultivated meat, that is 33,000 times less than the first cultivated burger developed by Mark Post and Peter Verstrate less than a decade ago that had a production cost of USD 330,000 73 . 3D bioprinting Additive manufacturing, the process of joining materials to make objects from computer-aided design model data, such as 3D printing, have opened tremendous opportunities in a broad spectrum of applications in several industry sectors. The integration of 3D printing into tissue engineering provides opportunities for many innovation solutions including regeneration medicine, in-vitro models, pharmaceutical and food industries and healthcare challenges and heralds’ new frontiers in medicine, pharmaceutical, and food industries 74 . Scientists from Osaka University used this method to print Wagyu beef 75 that resembles the real pieces of meat and reproduces its complex structure formed by muscle fibres, fat, and blood vessels. The fibres fabricated from stem cells using bioprinting were then arranged in 3D to reproduce the structure of the real Wagyu meat and sliced perpendicularly, like the traditional Japanese candy Kintaro-ame. Tendon-gel-integrated bioprinting used for the fibre cells’ fabrication could expand a culture meat toolbox and provide a valuable approach for constructing engineered steak-like meat. Precision fermentation The advancements in genome-based technologies enabled a transformation of the traditional fermentation process and development of precision fermentation that uses microbial hosts as ‘cell factories’ for producing specific functional ingredients 18 . This process has been used to produce animal-based proteins and can save water and land compared to traditional livestock farming with the added benefit of zero methane gas emission. For example, startups Perfect Day (US) 76 and Eden Brew (Australia) 77 use this approach to produce the same proteins found in cow milk and create synthetic milk that have similar taste, look, and feel to dairy milk. While the technology has significant potential to address environmental challenges, there is an on-going discussion of its downsides, for example, in the case of synthetic milk, its potential impact on to the dairy industry and conventional agriculture and the prospect of pushing out low-tech or small-scale dairy farms. However, to do so, the industry must grow exponentially and build new manufacturing infrastructure (e.g., fermentation tanks, bioreactors) that would require a considerable amount of investment. Another startup that uses precision fermentation is Air Protein (US) 78 . It uses microbes to transform carbon dioxide from air into meat that originates from the 1970s space programme where NASA scientists explored a way to feed astronauts on long space journeys by transforming elements in the air that the astronauts breathed into proteins 79 . The end fermentation product is a versatile protein-rich flour, which has a similar amino acid profile as meat protein and can be turned into any food using a combination of pressure, temperature, and other technologies. The manufacturing process has climate-saving potential: it is carbon-negative and compared to beef, uses 1.5 million times less land and reduces water usage 15,000 times. Like with other cultured meat challenges, the most crucial aspect is making the process cost competitive. Published techno-economic analysis indicated a production range in a hypothetical commercial-scale facility ranging from USD 17 to USD 65 per kilogram where the largest cost drivers include culture media, bioreactors, and labour 12 . New technologies and discoveries continue to fuel the field of alternative protein sources. Alternative protein sources used to fabricate meat, fish and diary food products can help to address food security challenges and mitigate environmental issues, by significantly reducing emissions and requiring far less land. For example, based on a life cycle assessment, plant-based meat can cut emissions by 90 percent, and use 99 percent less land and water compared to conventional meat 80 . The current alternative proteins sources include insect-, fungi- and plant-based proteins and cell-based proteins grown from animal cells in the form of cultivated meat and fish. Producing food from alternative proteins has made a big leap forward in the past decade with plant-, fungi- and insect-based food available in grocery shops and food made from meat substitutes being served in restaurants. However, there are still a number of challenges to overcome before these products will become a commodity accessible to everyone. The main challenges (Fig.  5 ) include consumer acceptance driven by their ability to mimic traditional food in terms of texture, taste and appearance; affordability due to high cost associated with a complex technological process and its scalability as well as raw materials cost and a development of regulatory framework to enable market accessibility that requires more research to demonstrate their long-term safety profile and potential health risks. The main challenges for alternative proteins food to become a commodity could be divided into three groups: (1) Affordability, (2) Acceptability and (3) Accessibility that form 3As framework. Affordability challenge is driven by high cost associated with a complex technological process and its scalability as well as raw materials cost. Acceptability challenge deals with consumer acceptance of alternative protein proteins products and their ability to mimic traditional food in terms of texture, taste, and appearance. Accessibility challenge is ability to place these products on the market and rely on a regulatory framework that is in a development stage and requires more research to demonstrate their long-term safety profile and potential health risks. Multi-dimensional efforts are being put in place to address these challenges that include interdisciplinary and integrated research, new partnerships and global alliances and continuous investment from both private and public sources. Specific examples of these activities are presented for each of the 3As challenges. Interdisciplinary and integrated research, new partnerships and global alliances and continuous investment from both private and public sources 81 will enable these issues to be addressed. The Importance of alternative protein sources to achieve national economic growth, sustainability and food production objectives have been recognised by both government and non-government organisations including forming cross-stakeholders’ partnerships, e.g. the U.S.-based Alliance for Meat, Poultry, and Seafood Innovation, the APAC Society for Cellular Agriculture, and Cellular Agriculture Europe launched a new global alliance to collaborate on regulatory work, consumer research, and nomenclature 12 . The above creates fertile ground for startups in this sector to continue evolving and to deliver breakthrough innovation by bringing fresh perspectives, creativity, a willingness to take risks, targeting niche issues (in particularly, sensorial perception barriers) and their ability to bridge between the latest advancements in academic research and the go-to-market resources of large companies. Prevalence of undernourishment worldwide 2005-2022. Statista https://www.statista.com/statistics/264901/proportion-of-starving-people-in-the-world-population/#:~:text=Prevalence%20of%20undernourishment%20worldwide%202005%2D2022&text=After%20the%20share%20of%20people,were%20undernourished%20worldwide%20that%20year (2023). Ranganathan, J., Waite, R., Searchinger, T. & Hanson, C. World Resources Report: Creating a Sustainable Food Future https://www.wri.org/insights/how-sustainably-feed-10-billion-people-2050-21-charts (2018). Savary, S. et al. The global burden of pathogens and pests on major food crops. Nat. Ecol. Evol. 3 , 430–439 (2019). Article   PubMed   Google Scholar   Creating a Sustainable Food Future: A Menu of Solutions. https://www.wri.org/research/creating-sustainable-food-future (2019). Kumar, K. et al. Genetically modified crops: current status and future prospects. Planta 251 , 91 (2020). Article   CAS   PubMed   Google Scholar   Dai, J., Bai, M., Li, C., Cui, H. & Lin, L. Advances in the mechanism of different antibacterial strategies based on ultrasound technique for controlling bacterial contamination in food industry. Trends Food Sci. Technol. 105 , 211–222 (2020). Article   CAS   Google Scholar   Reyns, P. et al. A review of combine sensors for precision farming. Precis. Agric. 3 , 169–182 (2002). Article   ADS   Google Scholar   Sourav, A. & Emanuel, A. W. R. Recent trends of big data in precision agriculture: a review. IOP Conf. Ser.: Mater. Sci. Eng. 1096 , 012081 (2021). Article   Google Scholar   Kamilaris, A., Fonts, A. & Prenafeta-Boldύ, F. X. The rise of blockchain technology in agriculture and food supply chains. Trends Food Sci. Technol. 91 , 640–652 (2019). Drago, E., Campardelli, R., Pettinato, M. & Perego, P. Innovations in smart packaging concepts for food: an extensive review. Foods 9 , 1628 (2020). Article   CAS   PubMed   PubMed Central   Google Scholar   Ben-Ary, T., &. Levenber, S. Tissue engineering for clean meat production. Front. Sustain. Food https://doi.org/10.3389/fsufs.2019.00046 . (2019). Good Food Institute State of the Industry Report ‘Cultivated meat and seafood’ https://gfi.org/wp-content/uploads/2023/01/2022-Cultivated-Meat-State-of-the-Industry-Report-2-1.pdf . (2022). The GFI report provides a comprehensive overview of the science of cultivated meat and challenges that must be addressed for its commercialisation as well as its current development status . Andreoli, V., Bagliani, M., Corsi, A. & Frontuto, V. Drivers of protein consumption: a cross-country analysis. Sustainability 13 , 7399 (2021). The paper explores the relationship between per capita income and animal and vegetal protein consumption . Béné, C. & Lundy, M. Political economy of protein transition: battles of power, framings and narratives around a false wicked problem. Front. Sustain. 4 , 1098011 (2023). Wood, P. & Tavan, M. A review of the alternative protein industry. Curr. Opin. Food Sci. 47 , 100869 (2022). Lima, M., Costa, R., Rodrigues, I., Lameiras, J. & Botelho, G. A narrative review of alternative protein sources: highlights on meat, fish, egg and dairy analogues. Foods 11 , 2053 (2022). Munialo, C. D. A review of alternative plant protein sources, their extraction, functional characterisation, application, nutritional value and pinch points to being the solution to sustainable food production. Int J. Food Sci. Technol. https://doi.org/10.1111/ijfs.16467 (2023). Netsanet Shiferaw Terefe, N. S. Food Engineering Innovations Across the Food Supply Chain . 89-106 (ed. Juliano, P., et al.) (Academic Press, 2022). He, J., Evans, N. M., Liu, H. & Shao, S. A review of research on plant-based meat alternatives: driving forces, history, manufacturing, and consumer attitudes. Compr. Rev. Food Sci. Saf. 19 , 2639–2656 (2020). Jedrzejczak-Silicka, M. History of cell culture. new insights into cell culture technology. InTech https://doi.org/10.5772/66905 (2017). Edelman, P. D., McFarland, D. C., Mironov, V. A. & Matheny, J. G. Commentary: In vitro-cultured meat production. Tissue Eng. 11 , 659–662 (2005). PMID: 15998207. Broucke, K., Els Van Pamel, E., Van Coillie, E., Herman, L. & Van Royen, G. Cultured meat and challenges ahead: A review on nutritional, technofunctional and sensorial properties, safety and legislation. Meat Sci. 195 , 109006 (2023). FoodData Central (an integrated data system that provides expanded nutrient profile data and links to related agricultural and experimental research). https://fdc.nal.usda.gov/ (2023). FooDB (a web-based resource on food constituents, chemistry and biology and provides information on both macronutrients and micronutrients). https://foodb.ca/ (2022). Malaysian Food Composition Database (FCD): the database provides food composition and nutrients of food materials. https://myfcd.moh.gov.my/ (2015). Al-Sarayreh, A. Inverse design and AI/Deep generative networks in food design: a comprehensive review. Trends Food Sci. Technol. 138 , 215–228 (2023). Anything you eat, you can eat vegan! https://www.eatkind.co/GB (Woodhead Publishing, 2023). Meyer-Rochow, V. Can insects help to ease the problem of world food shortage. Search 6 , 261–262 (1975). Google Scholar   Akhtar, Y., & Isman, M. B. In Woodhead Publishing Series in Food Science, Technology and Nutrition. Proteins in Food Processing (Second Edition). (ed. Rickey Y. Yada) 263-288. https://doi.org/10.1016/B978-0-08-100722-8.00011-5 (2018). Weru, J. et al. Comparison of healthfulness of conventional meats and edible insects in Sub-Saharan Africa using three nutrient profiling models. Bull. Natl Res Cent. 46 , 43 (2022). Orkusz, A. Edible Insects versus Meat-Nutritional Comparison: Knowledge of Their Composition Is the Key to Good Health. Nutrients 13 , 1207 (2021). This article compares the nutritional value of edible insects and meat and shows that the content of individual nutrients in both insects and meat varies significantly . Payne, C. L., Scarborough, P., Rayner, M. & Nonaka, K. Are edible insects more or less ‘healthy’ than commonly consumed meats? A comparison using two nutrient profiling models developed to combat over- and undernutrition. Eur. J. Clin. Nutr. 70 , 285–291 (2016). Kim, T. K., Yong, H. I., Kim, Y. B., Kim, H. W. & Choi, Y. S. Edible insects as a protein source: a review of public perception, processing technology, and research trends. Food Sci. Anim. Resour. 39 , 521–540 (2019). Article   PubMed   PubMed Central   Google Scholar   Edible Insects Market Size & Share Analysis - Growth Trends & Forecasts (2023 - 2028). Mordor Intelligence Report https://www.mordorintelligence.com/industry-reports/edible-insects-market (2023). Kröger, T., Dupont, J., Büsing, L. & Fiebelkorn, F. Acceptance of insect-based food products in western societies: a systematic review. Front. Nutr. (Lausanne) 8 , 759885–759885 (2022). Glasne, J. Surprisingly Large Sums Have Gone Into Bug Farming Startups. https://news.crunchbase.com/venture/foodtech-bug-farming-startups/ (2023). Tyson Foods Announces Partnership with Protix for More Sustainable Protein Production. https://protix.eu/wp-content/uploads/TysonFoodsAndProtixPartnership.pdf (2023). Ÿnsect launches its first product in the US with partner pure simple true LLC. https://www.ynsect.com/2021/11/09/ynsect-launches-its-first-product-in-the-us-with-partner-pure-simple-true-llc/ (2021). Insect industry abuzz with new knowledge sharing hub. https://www.aciar.gov.au/media-search/news/insect-industry-abuzz-new-knowledge-sharing-hub (2022). Insectrial Revolution: Shaping the future of sustainable protein. https://iuk.ktn-uk.org/casestudy/shaping-the-future-of-sustainable-protein/ (2021). Food and Agriculture Organisation of United Nation Report ‘Looking at edible insects from a food safety perspective. Challenges and opportunities for the sector’ https://doi.org/10.4060/cb4094en (2021). The report provides an overview of the various food safety issues associated with edible insects and the regulatory frameworks and highlights major challenges that would need to overcome to have a more global reach . Food Standard Agency Report ‘Technical Report Risk Profile on Edible Insects’ https://www.food.gov.uk/research/edible-insects-summary (2022). World-first: Ÿnsect reveals the first high-density genotyping chip for insect breeding. https://www.ynsect.com/2023/06/06/world-first-ynsect-reveals-the-first-high-density-genotyping-chip-for-insect-breeding/ (2023). From data farm to bug farm. https://betahatch.com/innovation/ (2023). Shop Hey Planet. https://www.hey-planet.com/collections/webshop (2024). We’ve opened a permanent bug-restaurant! https://www.yumbug.com/book-table (2024). Karin, M. E., Wendin, M., Nyberg, E. Factors influencing consumer perception and acceptability of insect-based foods. Current Opinion in Food Science, 40, 67-71 https://doi.org/10.1016/j.cofs.2021.01.007 (2021). This paper presents different factors influencing consumer perception and acceptability of insect-based foods and their complexity in influencing consumers’ perceptions and acceptability of insects as food . Bei-Zhong Han, B. Z., Rombouts, F. M. & Nout, M. J. R. A Chinese fermented soybean food. Int. J. Food Microbiol. 65 , 1–10 (2001). Alternative protein manufacturers and brands. https://gfi.org/resource/alternative-protein-company-database/#manufacturers-and-brands (2024). Good Food Institute State of the Industry Report ‘Pant-based meat, seafood, egg and dairy.’ https://gfi.org/wp-content/uploads/2023/01/2022-Plant-Based-State-of-the-Industry-Report.pdf (2022) The GFI report in-depth understanding of the plant-based protein market, issues, and opportunities and details some of the promising developments . FWW analysis of ‘Top Meat Substitute Makers (Refrigerated/ Frozen), 2019.’ (eds. Burton, Virgil L. and Robert S. Lazich). Market Share Reporter. 31st edn. Detroit: Gale (2021). Clark, D. Germany Unveils ‘Groundbreaking’ Investment In Plant-Based Food. https://plantbasednews.org/culture/law-and-politics/germany-investment-plant-based-future/ (2023). Biomimicry is our engine. https://www.novameat.com/our-technology (2023). Our Extrusion: Putting the Tech in Texture. https://www.meattheend.tech/our-technology (2021). Watson, E. Meet the founders: Lypid tackles fat, the final frontier for alt meat. https://agfundernews.com/meet-the-founders-lypid-tackles-fat-the-final-frontier-for-alt-meat (2023). Vegan Salmon Filet becomes first 3D printed product available in supermarkets. https://www.revo-foods_1.prowly.com/260307-vegan-salmon-filet-becomes-first-3d-printed-product-available-in-supermarkets (2023). Creating unique fungi solutions. https://mycorena.com/technology (2024). Alessandrini, R., Brown, M. K., Pombo-Rodrigues, S., Bhageerutty, S., He, F. J. & MacGregor, G. A. Nutritional quality of plant-based meat products available in the UK: a cross-sectional survey. Nutrients 13 , 4225 (2021). Elhalis, H., See, X. Y., Osen, R., Chin, X. H. & Chow, Y. Significance of fermentation in plant-based meat analogs: a critical review of nutrition, and safety-related aspects. Foods 12 , 3222 (2023). Fifty Years Hence. https://www.nationalchurchillmuseum.org/fifty-years-hence.html (1931). Cultivated meat. It’s science (but not rocket science). https://upsidefoods.com/innovation (2024). GOOD Meat Gets Full Approval in the U.S. for Cultivated Meat. https://www.goodmeat.co/all-news/good-meat-gets-full-approval-in-the-us-for-cultivated-meat (2023). Doenecke, P. Aleph Farms Seeks Swiss Regulatory Approval for Cultivated Meat. https://www.bloomberg.com/news/articles/2023-07-27/aleph-farms-seeks-swiss-regulatory-approval-for-cultivated-meat-lkleralp (2023). Meatable reveals its groundbreaking pork sausages product for the first time. https://meatable.com/news-room/ (2022). Kateman, B. Cell-Cultured Seafood Isn’t just An Idea; It’s A Reality. https://www.forbes.com/sites/briankateman/2022/06/06/cell-cultured-seafood-isnt-just-an-idea-its-a-reality/?sh=328115b3146d (2022). The Journey of Avant Meats. https://www.avantmeats.com/about-us (2024). Kahn, J. French startup promises cruelty-free foie gras, grown in a lab. https://fortune.com/2021/07/14/foie-gras-lab-grown-gourmey-startup-ethical-food/ (2021). World’s first hybrid meat innovation centre to open in Singapore in 2023. https://www.edb.gov.sg/en/business-insights/insights/world-s-first-hybrid-meat-innovation-centre-to-open-in-singapore-in-2023.html (2022). National Vision for Engineering Biology. https://assets.publishing.service.gov.uk/media/656de8030f12ef07a53e01ac/national_vision_for_engineering_biology.pdf (2023). Kessler, J. Singapore approves sale of lab-grown meat in world first. https://www.standard.co.uk/news/singapore-lab-grown-meat-chicken-nuggets-b141083.html (2020). Post, M. J.& Hocquette, J. F. Chapter 16 - New Sources of Animal Proteins: Cultured Meat, Editor(s): Peter P. Purslow, In Woodhead Publishing Series in Food Science, Technology and Nutrition, New Aspects of Meat Quality, Woodhead Publishing. Pages 425–441 (2017). Poinski, M. SCiFi Foods reduces the cost of cell-based beef 1000-fold. https://www.fooddive.com/news/scifi-foods-cell-based-cultivated-beef-1000-cost-reduction/627122/ (2022). Baker, A. The Cow That Could Feed the Planet. https://time.com/6109450/sustainable-lab-grown-mosa-meat/ (2021). Ramadan, Q. & Zourob, M. 3D bioprinting at the frontier of regenerative medicine, pharmaceutical, and food industries. Front. Med. Technol. 2 , 607648 (2021). Kang, D. H., Louis, F. & Liu, H. et al. Engineered whole cut meat-like tissue by the assembly of cell fibers using tendon-gel integrated bioprinting. Nat. Commun. 12 , 5059 (2021). Article   ADS   CAS   PubMed   PubMed Central   Google Scholar   Championing a more resilient future. https://perfectday.com/precision-fermentation-alliance/ (2023). Partnering with nature to meet dairy protein demand sustainably. https://www.edenbrew.com.au/product (2023). Lev-Ram, M. Meet Lisa Dyson, who looked to the space program for new ways to create nutritional food. https://fortune.com/2023/08/10/lisa-dyson-founders-forum-2023/ (2023). Carbon Capture Process Makes Sustainable Oil. https://spinoff.nasa.gov/Spinoff2019/ee_4.html (2019). Heller, M. C. & Keoleian, G. A. Beyond Meat’s Beyond Burger Life Cycle Assessment: A detailed comparison between a plant-based and an animal-based protein source. CSS Report, University of Michigan: Ann Arbor 1-38 (2018). https://hdl.handle.net/2027.42/192044 . A deeper dive into alternative protein investments in 2022: The case for optimism. https://gfi.org/blog/alternative-protein-investments-update-and-outlook/ (2023). Download references Author information Authors and affiliations. Department of Biosciences, Durham University, DH1 3LE, Durham, UK Elena Lurie-Luke You can also search for this author in PubMed   Google Scholar Contributions E.L.L. conceptualised the manuscript and was responsible for all aspects of its preparation. Corresponding author Correspondence to Elena Lurie-Luke . Ethics declarations Competing interests. The author declares no competing interests. Peer review Peer review information. Nature Communications thanks Federico Casanova and Marcelle Machluf for their contribution to the peer review of this work. Additional information Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Rights and permissions Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ . Reprints and permissions About this article Cite this article. Lurie-Luke, E. Alternative protein sources: science powered startups to fuel food innovation. Nat Commun 15 , 4425 (2024). https://doi.org/10.1038/s41467-024-47091-0 Download citation Received : 18 December 2023 Accepted : 20 March 2024 Published : 28 May 2024 DOI : https://doi.org/10.1038/s41467-024-47091-0 Share this article Anyone you share the following link with will be able to read this content: Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative By submitting a comment you agree to abide by our Terms and Community Guidelines . If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate. Quick links Explore articles by subject Guide to authors Editorial policies Sign up for the Nature Briefing: Translational Research newsletter — top stories in biotechnology, drug discovery and pharma. 423 COMMENTS Full article: A review of renewable energy sources, sustainability The aim of the paper is to ascertain if renewable energy sources are sustainable and examine how a shift from fossil fuel-based energy sources to renewable energy sources would help reduce climate change and its impact. ... Research into alternate sources of energy dated back in the late 90s when the world started receiving shock from ... A comprehensive study of renewable energy sources: Classifications The aim of this review paper is to understand and study further the current RE technologies such as solar energy, hydro energy, wind energy, bioenergy, geothermal energy, and hydrogen energy. ... Hydrogen energy sustainable since it can be generated from renewable and non-renewable energy sources [245], thus can be utilized in various sectors ... Towards Sustainable Energy: A Systematic Review of Renewable Energy The use of renewable energy resources, such as solar, wind, and biomass will not diminish their availability. Sunlight being a constant source of energy is used to meet the ever-increasing energy need. This review discusses the world's energy needs, renewable energy technologies for domestic use, and highlights public opinions on renewable energy. A systematic review of the literature was ... (PDF) The Need For Renewable Energy Sources The major sources of renewable. energy include solar, wind, biomass, geothermal, hydropower. and tidal energy. Non renewable energy, such as coal, natural. gas and oil, require costly explorations ... Clean energy can fuel the future More energy efficiency means less pollution, and energy efficiency has increased by around 2% annually in the past few years. But meeting the target for 2030 — to double the rate of the 1990 ... The role of renewable energy in the global energy transformation The energy transition must reduce emissions substantially, while ensuring that sufficient energy is available for economic growth. The analysis shows that the CO 2 emissions intensity of global economic activity needs to be reduced by 85% between 2015 and 2050, and CO 2 emissions need to decline by more than 70% compared to the Reference Case in 2050. . The result is an annual decline of ... (PDF) Renewable Energy Sources fuel and two-third of the global energy demand is fulfilled by renewable energy sources. According to a report by Bloomberg New Energy Finance, b y 2050 about 50% of the. global energy demand is ... A Global Assessment: Can Renewable Energy Replace Fossil Fuels ... Our study evaluated the effectiveness of using eight pathways in combination for a complete to transition from fossil fuels to renewable energy by 2050. These pathways included renewable energy development; improving energy efficiency; increasing energy conservation; carbon taxes; more equitable balancing of human wellbeing and per capita energy use; cap and trade systems; carbon capture ... Renewable energy A large-scale analysis, comprising 1 million water bodies worldwide, shows that floating photovoltaics could contribute 16%, on average, of the electricity demands of some countries. R. Iestyn ... Towards Sustainable Energy: A Systematic Review of Renewable Energy About other renewable energy sources, Turkey had the largest share in generating energy from wind and solar energy, with an annual growth rate of (88.03%, 98.22%), respectively. Frontiers Energy security and sustainability are undeniably the main concerns in combatting climate change. While an immediate call for all-green and renewable energy seems to be impossible due to huge financial implications and inadequate supporting energy structure, an alternative to fossil fuels needs to be established. Natural gas, a naturally occurring fossil gas is a cleaner energy source option ... Advances in Alternative Sources of Energy Worldwide, energy is harnessed from fossil fuels as well as from alternative sources of energy. However, for energy generation, fossil fuels are exploited at a larger scale, and the role of alternative energy sources is not substantial. In future, the contribution of renewable energy sources will be crucial for energy sustainability. Renewable energy as an alternative source for energy management in This paper comprehensively reviews and explores renewable energy as an alternative energy source for efficient energy management in the agricultural sector. ... Renewable energy sources like wind and solar can be used to power farm vehicles in a way that is good for the economy ... Sardar Patel Renewable Energy Research Institute, Vallabh ... PDF A Review of Renewable Energy Supply and Energy Efficiency Technologies Research published in this series may include views on policy, but the institute itself takes no institutional policy positions. ... accident was a turning point in the call for alternative energy sources. Renewable energy is ... In this paper, we discuss alternative technologies for enhancing renewable energy deployment and energy use efficiency. Alternative Energy Sources in Developing and Developed Regions Resources is an international peer-reviewed open access monthly journal published by MDPI. Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. A critical review of the integration of renewable energy sources with Wind power, solar power and water power are technologies that can be used as the main sources of renewable energy so that the target of decarbonisation in the energy sector can be achieved. However, when compared with conventional power plants, they have a significant difference. The share of renewable energy has made a difference and posed various challenges, especially in the power ... Climate change impacts on renewable energy supply The increase in renewable energy use leads to a decline in fossil fuel and nuclear energy use in most of the regions, resulting in a 1-2% reduction in cumulative CO 2 emissions (2015-2100). In ... Renewable energy for sustainable development in India: current status Gross electricity generation from renewable energy—according to sources. Table 16 shows the gross electricity generation from renewable energy—source-wise. It can be concluded from the table that the wind-based energy generation as per 2017-2018 is most prominent with 51.71%, followed by solar energy (25.40%), Bagasse (11.63%), small ... Frontiers Introduction. In response to the advantages of renewable energy (Gullberg et al., 2014), many countries and regional organizations have entered into cooperative targeted renewable energy initiatives (Anand et al., 2021; Mohan, 2021; Sasmita and Sidhartha, 2021).Existing research on renewable cooperation (Feng et al., 2020) is mainly focused on a comprehensive analysis of the renewable energy ... A real options approach to renewable electricity generation in the The Philippines is making a significant stride to become energy independent by developing more sustainable sources of energy. However, investment in renewable energy is challenged by competitive oil prices, very high investment cost for renewable energy, and high local electricity prices. This paper evaluates the attractiveness of investing in renewable energy sources over continue using oil ... Do alternative energy sources displace fossil fuels? Electricity production from non-fossil-fuel sources has a significant coefficient of −0.079, very similar to what was found in model 1. This coefficient indicates that close to 13 kWh (1/0.079 ... Net Zero by 2050 Instead of fossil fuels, the energy sector is based largely on renewable energy. Two-thirds of total energy supply in 2050 is from wind, solar, bioenergy, geothermal and hydro energy. Solar becomes the largest source, accounting for one-fifth of energy supplies. Solar PV capacity increases 20-fold between now and 2050, and wind power 11-fold. A review on alternative fuels in future energy system The transition toward a 100% Renewable Energy System is a complex process with different technical and economic challenges. In order to achieve predetermined goals, several steps should be carried out simultaneously, including increment of energy efficiency, savings in primary energy consumption, and finally, deployment of variable renewable energy sources (VRES) [1]. Sustainability A large share of non-renewable energy use in egg production is due to the operation of heating, ventilation, and air conditioning (HVAC) systems. ... this paper, along with the future research opportunities it provides, will be valuable to egg farmers, renewable energy industries, and HVAC engineers. ... Energy Sources Part Recovery Util ... Causes and Effects of Climate Change Globally, a bit more than a quarter of electricity comes from wind, solar and other renewable sources which, as opposed to fossil fuels, emit little to no greenhouse gases or pollutants into the ... Environment In 2018, we launched the China Clean Energy Fund to accelerate renewable progress in China. Together with our suppliers, we've invested in 1,000 megawatts of clean energy. Additionally, through the RE100 initiative, we partner with the world's most influential businesses that have committed to using 100% renewable electricity. Search Results Renewable energy. Reducing transport emissions. Energy data. Energy efficiency. Energy markets. Energy programs. Energy security. Energy supply. Energy workforce. ... Science and research Undertaking research and collecting data to support informed decisions and policies. Climate change. Australia's biological resources ... Infrastructure eXCHANGE: Funding Opportunity The required Concept Paper due date for this FOA is 06/13/2024 at 5PM ET. ... lowered energy burdens, increased access to renewable energy, improved air quality, increased public participation in energy decision-making processes, and improved quality of life for local residents. ... over a 5-year period from FY 2022 through 2026 to develop ... Renewable energy present status and future potentials in India: An The renewable energy sources is renewed and environmental friendly in nature. ... All authors of this research paper have directly participated in the planning, execution, or analysis of this study. ... International Journal of Renewable Energy Research, 9 (1) (2019), pp. 309-342. Google Scholar. Charles et al., 2019a. Alternative protein sources: science powered startups to fuel food When it comes to finding an alternative, there are three main options to consider: (1) using a replacement, (2) modifying existing non-animal/non-fish sources of proteins, and (3) making an ... assignment essay homework paper phd report resume review speech thesis