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This paper is the editorial for the virtual special issue (VSI) of Renewable and Sustainable Energy Reviews (RSER) dedicated to three Sustainable Development of Energy Water and Environment Systems (SDEWES) Conferences held in 2022, namely: (i) the 5th South East European Conference SEESDEWES 2022 held from May 22 to 26, 2022 in Vlore, Albania; (ii) the 3rd Latin American LASDEWES 2022 held from July 24 to 28, 2022 in Sao Paulo, Brazil and (iii) the 17th SDEWES 2022 held from November 6 to 10, 2022 in Paphos, Cyprus. The VSI collected both high quality review papers and original research articles presented at these conferences, aligning with the aims and scope of RSER. Following a rigorous peer review process, seventeen articles were accepted and published. These articles explore techniques and technologies essential for advancing feasible Renewable and Sustainable Energy Systems. Spanning multidisciplinary topics, many of them address almost all the Sustainable Development Goals, offering feasible solutions for much-needed decarbonization pathways. • The VSI SDEWES 2022 presents the ready solutions for Renewable and Sustainable Energy Systems. • Five clusters for presenting the Renewable and Sustainable energy cutting edge solutions. • The positioning in the scientific context of the Renewable and Sustainable Energy Systems. • Feasible solutions for much-needed decarbonization pathways. [ABSTRACT FROM AUTHOR]

Rapid growth in population and economic development in Iran and its neighboring countries has resulted in a dramatic increase in electricity demand over the past few years. A substantial amount of electricity must be produced to meet this growing demand in this region. By installing conventional fossil power plants, using renewable energy, and interconnecting with neighboring countries, this growing demand can be accomplished. The main aim of this research is to identify prospects and challenges in the electrical sector around Iran. To this end, this paper evaluates the existing and future state of the electrical sector in Iran and its neighboring countries. Despite the fact that there is still a long way to go in terms of renewable energy in this region, there are some promising targets for the future that will allow fossil fuels to be replaced effectively. Notwithstanding this, we should point out that a number of cross-border interconnection projects are being pursued by Iran and its neighbors in order to integrate their networks and supply this growing demand. Finally, this study presents an overview of the future prospects and challenges of electricity capacity expansion, cross-border interconnections, and electricity transmission corridors in this region. The review results provide comprehensive background knowledge to all the researchers in order to investigate further into the field. This paper assists energy policy makers regarding the development of sustainable energy planning. • •In addition to providing a general overview of the geographical location, population growth, and economic indicators of Iran and its neighboring countries, this paper presents the current state of the Iranian electricity sector and its neighboring countries in light of the trends in electricity production, energy mix, price, and exports and imports. • •This paper explores the existing and future states of electricity capacity expansion in the region, specifically focusing on renewable energy sources. • •The existing and future states of cross-border electricity interconnections are examined to present a comprehensive overview of the cross-border interconnections in this region. • •This region's potential electricity transmission corridors are proposed to create the opportunity to transmit electricity across countries. [ABSTRACT FROM AUTHOR]

Wind energy is a promising and efficient renewable energy source for electrical energy production. Globally, there has been a significant increase in the development of wind energy conversion systems (WECS). The world is interested in grid codes applying for facing various problems because of large capacity WECS integration with the grid, including the stability and reliability of electrical grid and power quality. Low voltage ride through (LVRT) capability is an important requirement of grid codes. LVRT means that the wind turbine is still connected to the grid during grid voltage sags. This is essential for ensuring that no generated power by wind turbines is lost due to grid disturbances. To deal with these issues simultaneously, this paper presents a comprehensive review of LVRT methods for the most common wind generators; squirrel cage induction generator (SCIG), doubly fed induction generators (DFIG), and permanent magnetic synchronous generator (PMSG). Moreover, the overall view of optimization techniques that are used to enhance LVRT capability for WECSs and the configurations of WECS are investigated. A comprehensive and a useful summary for the recent work in literature regarding LVRT methods for these three wind generators with comparisons and discussion are introduced. To achieve this aim, more than 200 articles are organised and only 135 papers are presented in this review. • Comprehensive review of low voltage ride through methods for the most common wind generators. • Overall view on optimization techniques that are used to enhance LVRT capability. • The configurations of wind energy conversion system are investigated. • Useful summery for the recent work in literature regarding LVRT methods is introduced. [ABSTRACT FROM AUTHOR]

This paper is the editorial for the virtual special issue (VSI) of Renewable and Sustainable Energy Reviews (RSER) dedicated to the 16th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES 2021) held from October 10 to 15, 2021 in Dubrovnik, Croatia. The VSI collected both high quality review papers and original research articles presented at the SDEWES Conference in 2021 belonging to the aims and scope of RSER. After a scrutinizing peer review process, 28 articles were accepted and published. These articles deal with techniques and technologies to board on the feasible Renewable and Sustainable Energy Systems. Many of them are multidisciplinary articles addressing almost all the Sustainable Development Goals (SDGs) and providing feasible solutions to the strongly needed decarbonization pathways. • The VSI SDEWES 2021 covers the feasible Renewable and Sustainable Energy Systems. • An overview of the Renewable and Sustainable energy cutting edge techniques. • An overview of the Renewable and Sustainable energy cutting edge technologies. • Feasible solutions to the strongly needed decarbonization pathways. [ABSTRACT FROM AUTHOR]

Conventional petrol vehicles emit a substantial quantity of greenhouse gases, leading to increasingly serious global warming problems. The expansion and development of renewable power generation technologies is conducive in promoting the use of electric vehicles, which are more environmentally friendly. This paper proposes a multi-objective power expansion model considering renewable energy policy objectives. The model regards the problem as a multi-period optimisation task, taking the newly installed capacity and the power generation capacity of each power generation technology as decision variables, and simulating the uncertain factors in the planning process using Geometric Brownian Motion and Monte Carlo approaches. The optimisation objective of the model is to minimise expected costs, reduce risk and environmental impacts, and incorporate changing policy objectives into the constraints to meet policy makers' expectations for renewable energy development. Then, a decentralised target search-based multi-objective evolutionary algorithm is proposed to solve the model. Its effectiveness is verified by a numerical example using real data from the Chinese power system. The experimental results show that the proposed algorithm exhibits improved performance compared with benchmark algorithms and provides high quality and diverse Pareto-optimal solutions to decision makers. Finally, the optimal plans for power expansion and generation mix under different preferences and policy objectives are discussed and corresponding recommendations are made. [Display omitted] • Planning for the expansion of power generation under uncertainties is determined. • Strategies for the expansion of power generation towards renewable energy are optimised. • A novel multi-objective evolutionary algorithm with a constraint handling method is developed. • The impact of multiple renewable energy policies on power generation expansion planning is discussed. [ABSTRACT FROM AUTHOR]

Electrified vehicles provide an effective solution to address the unfavorable impacts of fossil fuel use in the transportation sector. Energy management strategy (EMS) is the core technology supporting the outstanding performance of electrified vehicles. However, technical bottlenecks in conventional control methods, such as poor real-time performance and limited generalization capability, significantly hinder the development of energy management technology. The recent advances in deep reinforcement learning (DRL) hold enormous potential in addressing relevant problems. To this end, this paper systematically surveys DRL-based EMSs. First, DRL algorithms and useful DRL extensions are briefly reviewed. Next, a comprehensive literature survey of pioneering and representative working is presented. The effectiveness and configuration methods of DRL in energy management issues, as well as a guideline for DRL-based EMSs in different vehicular structures, are appropriately analyzed and summarized. Finally, the main challenges and potential solutions are extracted to enhance further real-world implementation. [Display omitted] • Theoretical overview of DRL algorithms that are valuable for energy management. • Summary of pioneering and representative studies on DRL-based EMSs. • Analysis of the effectiveness and configuration methods of DRL in energy management. • Guidelines for applying various DRL methods in different vehicular structures. • Discussion of challenges and potential solutions for real-world implementation. [ABSTRACT FROM AUTHOR]

This paper reviews the state-of-the-art on Hardware-In-The-Loop simulation methodologies and technologies applied in the research field of wave energy converters. It reveals important issues, such as an unclear taxonomy and representations of these methodologies, which are critical for the success of the approach, mostly during the design of experiments and presentation of results. Moreover, a classification approach to these methodologies is not found in the literature. Thus, a generic taxonomical and classification framework is developed to support the review process. This framework is built based on three taxonomic subsystems that the review shows to be effective in organizing the reviewed methodologies: simulated, real and interface subsystems. In particular, the definition of the interface subsystem is key to overcoming the limitations found in the methodological representations. Furthermore, this review borrows the term actionability to this approach to better describe the nuances and gaps between the reviewed case studies. It is found that the different technical implementations are easily organized with the proposed framework, and the results cover a wide range of wave energy converter development phases. Likewise, this review shows opportunities for improvements in the methodology and application to a wider number of new case studies. [Display omitted] • Hardware in the loop approach is currently described with unclear methodology. • Few case studies of the approach on wave energy converters have been published. • Review reveals research opportunities for methodological improvements. • Taxonomic framework proposed for systematic and clear methodological descriptions. • Technical information is provided for a wide range of device development phases. [ABSTRACT FROM AUTHOR]

The African continent is endowed with massive energy resources such as hydropower, solar, wind, natural gas, wave energy, and many more, yet it is the continent with the least energy supply in the world thereby resulting in a lack of sufficient energy to meet its growing energy demand. Though the continent holds 100 GW of wind capabilities, the current installed capacity as at 2018 was 5.7 GW with countries in northern Africa as well as South Africa capturing over 90% of the wind energy share on the continent. Therefore, this paper reviews the wind energy industry in Africa by identifying the current installed and potential capacity of wind energy on the continent. The challenges faced by the wind energy industry such as policy, competition, technical and economic are also reviewed. Transitions, technological innovation systems, and strategic niche management theoretical sustainability transition framework as well as proposed pathways to overcome these prevailing challenges hindering the full exploration of the wind energy sector in Africa are also highlighted in order to uplift the continent's socio-economic status. Basically, this can be achieved through the adoption of strong 'political-will' by African national governments to drive wind energy development. There is also the need for institutional frameworks to ensure the practical adoption of new wind energy technologies. Furthermore, the major benefits Africa stands to gain from investment in wind energy are enumerated by comparing with the benefits realized by other countries' economies as a result of investing in the wind energy industry. For instance, cheap electricity, job creation, industrial growth, and eco-friendly energy source. • Reviewing wind energy industry in Africa and existing challenges. • The challenges faced by African's wind energy industry can be categorized under policy, competition, technical and economic. • Framework for transiting Africa's wind energy industry from small-scale production to large-scale commercial industry.. [ABSTRACT FROM AUTHOR]

This paper provides a comprehensive review on the status of renewable energy developments and hydrogen economy in the Middle East and North Africa region. This region is heavily reliant on fossil fuels for its domestic energy supply and is also considered a global energy exporter. In this regard, an overview of the current state of energy sector in the region is provided. Moreover, the region possesses great potential for renewable energy exploitation due to its climatic advantages. Therefore, the current status of renewable energy utilization within the region's various countries is reviewed by presenting several operational renewable energy-based plants and future projects for deployment of renewable power in the region. Green hydrogen is an important sustainable clean fuel, and its utilization is essential for both environmental preservation and energy security. Thus, the status of hydrogen production and utilization in the region is discussed considering the various operational systems and future hydrogen generation projects. The concept of source, system and service is also incorporated which considers the utilization of clean energy sources for sustainable hydrogen production through environmentally benign pathways. The potential deployment opportunities for the renewable hydrogen production are also discussed based on available renewable sources in the region. Moreover, this paper discusses the challenges of increasing renewable energy utilization in the region. Furthermore, this paper provides a road map for achieving renewable hydrogen economy including a reduction in domestic utilization of oil and gas sources, subsidization of renewable production sector, and financial support to hydrogen production and transportation infrastructure. • Providing an overview of the status of energy sector in the region. • Providing an overview of the status of renewable energy utilization in the region. • Discussing the challenges and opportunities of renewable and hydrogen energy development in the region. • Providing a road map for renewable hydrogen development in the region. [ABSTRACT FROM AUTHOR]

Smart Grid benefits from information and communications technology (ICT) to integrate data from different sources across the network. The growing market for electric vehicles (EV) and electric devices is increasing energy demand. To manage a large amount of complex intelligent equipment, EV charging and discharging, and data-intensive devices, a reliable modern smart grid with a service-oriented, secure, efficient, and cost-effective system is compelling. Cloud computing is a promising approach to achieve that objective as monitoring power grid data flow and data center management are the key. This paper proposes an optimization model for energy management within the power cloud. Our energy system model enables accessible services to computing resources and real-time data stream processing within an integrated environment. Using digital technology, the proper implementation of our model reduces costs and energy consumption and improves the smart grid reliability for customers and energy providers in a distributed manner. This paper presents the implementation of a three-procedure optimization algorithm within a novel Multi-Agent Cloud-fog Structure (MACS) to meet the requirements raised by smart grid communication and distribution. Our model promotes reliable energy consumption adjustments by end-users who can choose power supplied by solar, wind, geothermal, biomass, or other renewable sources or from non-renewable sources in ways that reveal opportunities for demand-supply balance and energy saving. • Comprehensive review of cloud approaches in the context of specific areas. • Enhancing dynamic energy network communications using a multiagent cloud-fog. • Considering IoT and advanced meter infrastructure integration in smart grid. • Optimization modeling development for energy network management in smart grid. • Detailed analysis of simulation results considering modeling assumptions. [ABSTRACT FROM AUTHOR]

Energy subsidies can incentivise the overconsumption of energy resources and contribute to other economic or social distortions. In this paper, an ex-post analysis is presented that explores the extent to which electricity subsidy reform could have reduced Iran's energy demand during the period 1984–2017. It also quantifies the techno-economic and environmental benefits that could have been achieved through such reforms. A time-varying econometric model is linked to an energy systems optimisation model. The former estimates electricity demand under different subsidy removal scenarios, and the latter identifies the cost-optimal generation mix to meet the demand. The results of cost-optimal transition pathways under subsidy removal scenarios are compared with the real-world energy system development during the study horizon. The comparison reveals that the subsidy reform could have reduced the total cumulative electricity consumption by 22%. Renewable share in power generation could have increased from 5% to 15%. Moreover, the reform combined with a cost-optimal generation pathway would have saved $69 billion and avoided 944 million tons of CO 2 emissions. The analysis also shows that every five-year delay in subsidy removal causes about 100 million tons of additional CO 2 emissions. Finally, the paper presents lessons learnt for future energy modelling. • An ex-post analysis quantifies the benefits of energy subsidy reform in the power sector. • The total cumulative electricity consumption could have been reduced by 22%. • Renewable share in power generation could have tripled. • Subsidy reforms combined with cost-optimal generation could have saved $69 billion. • The paper presents lessons learnt for future energy modelling. [ABSTRACT FROM AUTHOR]

Energy subsidies can incentivise the overconsumption of energy resources and contribute to other economic or social distortions. In this paper, an ex-post analysis is presented that explores the extent to which electricity subsidy reform could have reduced Iran's energy demand during the period 1984–2017. It also quantifies the techno-economic and environmental benefits that could have been achieved through such reforms. A time-varying econometric model is linked to an energy systems optimisation model. The former estimates electricity demand under different subsidy removal scenarios, and the latter identifies the cost-optimal generation mix to meet the demand. The results of cost-optimal transition pathways under subsidy removal scenarios are compared with the real-world energy system development during the study horizon. The comparison reveals that the subsidy reform could have reduced the total cumulative electricity consumption by 22%. Renewable share in power generation could have increased from 5% to 15%. Moreover, the reform combined with a cost-optimal generation pathway would have saved $69 billion and avoided 944 million tons of CO 2 emissions. The analysis also shows that every five-year delay in subsidy removal causes about 100 million tons of additional CO 2 emissions. Finally, the paper presents lessons learnt for future energy modelling. • An ex-post analysis quantifies the benefits of energy subsidy reform in the power sector. • The total cumulative electricity consumption could have been reduced by 22%. • Renewable share in power generation could have tripled. • Subsidy reforms combined with cost-optimal generation could have saved $69 billion. • The paper presents lessons learnt for future energy modelling. [ABSTRACT FROM AUTHOR]

This paper is the editorial for the virtual special issue (VSI) of Renewable and Sustainable Energy Reviews (RSER) dedicated to 4 SDEWES Conferences held in 2020, namely: (i) the 2nd Latin American Conference on Sustainable Development of Energy, Water and Environment Systems (LASDEWES 2020) held from February 9 to 12, 2020 in Buenos Aires, Argentina; (ii) the 1st Asia Pacific Conference on Sustainable Development of Energy, Water and Environment Systems (APSDEWES 2020) held from April 6 to 9, 2020 in Gold Coast, Australia; (iii) the 4th South East European Conference on Sustainable Development of Energy, Water and Environment Systems (SEESDEWES 2020) held from June 28, 2020 to July 2, 2020 in Sarajevo, Bosnia Herzegovina, and (iv) 15th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES 2020) held from September 1 to 5, 2020 in Cologne, Germany. The VSI collected both high quality review papers and original research articles presented at the 4 SDEWES conferences in 2020 belonging to the aims and scope of RSER. After a scrutinizing peer review process, 20 articles were accepted and published. These articles fall into four main areas: renewable energy cutting edge technologies, energy storage, energy modelling techniques and, climate and energy policy and impacts. Cross-areas articles belong to this Special Issue covering almost all the Sustainable Development Goals (SDGs). • The VSI SDEWES 2020 covers four main areas. • An overview of the renewable and sustainable energy challenges to be dealt. • Cross-areas studies help addressing SDGs. • The advances and the novel findings for the successful achievements of ambitious policy targets. [ABSTRACT FROM AUTHOR]

The development of renewable energy sources (RES) is considered to be a key instrument in addressing climate change. However, different RES have different potential and economic feasibility depending on country-specific conditions and mitigation ambitions. Understanding the relative importance of each RES could help policymakers focus their efforts on the most promising options. In this paper, we focus on Ukraine and explore the potential of biomass use under two mitigation scenarios – with 68% and 83% of greenhouse gas emissions reduction in 2050 relative to the 2010 level. First, using the TIMES-Ukraine energy system model, we show that biomass would play a major role in the future climate mitigation. If constrained at the baseline scenario level (due to political or other reasons), mitigation costs would be substantially higher – by 14.0–19.6 B € or 10.8–14.3 €/tCO 2 -eq., over the 2020–2050 time frame. Second, we quantify the importance of each biomass source. We show that woody biomass and bioliquids are the most important biofuels under the high-ambition climate scenario, while biowaste and bioliquids play a key role in the lower ambition pathway. Finally, we analyse the current policy environment in the context of future biomass development and conclude with a set of policy recommendations toward the realization of the biomass potential in Ukraine. We believe that findings presented in the paper would be relevant not only for supporting the decision-making process in Ukraine, but could also provide useful insights for other countries with similar conditions. • Two scenarios with 68% and 83% reduction in GHG emissions in 2050 relative to 2010. • Over 50% of all renewable energy is coming from biomass under both scenarios. • Bioenergy constraint increases mitigation costs by 10.8–14.3 EUR/tCO 2 or 2.4–3.2 times. • No significant impact of the biogas availability on the mitigation costs. • Constraining biowoods , bioliquids or biowaste increases costs by at least 35% each. [ABSTRACT FROM AUTHOR]

The gamut of geothermal energy research encompasses the studies aimed at harnessing the abundant and inexhaustible thermal energy within the Earth, and it ranges from heat transfer to the activity of thermophilic microorganisms, 3D printing, and additive manufacturing and impacts the NET ZERO endeavour of humanity. In this paper, computational social network analysis has been employed to discover the subfield clusters of geothermal energy research and further trace the key evolutionary routes from the research corpus. The development, limitations, and opportunities of each cluster are examined, and it becomes evident that the focus of research ranges from geothermal evaluation, long-term effects of borehole heat exchangers, shallow systems that employ urbanisation's ground heating, enhanced geothermal systems (EGS) for district heating, combined and hybridised geothermal power generating models, including multi-generation and poly-generation, geothermal fluids, reinjection and their dual nature, environmental effects in geothermal water and mineral scaling, enhanced geothermal systems aiming to increase permeability without causing seismicity, and finally to social acceptability. We address significant questions, such as whether the waste heat is compatible with the idea of green geothermal heat and the elimination of pollutants and find that further R&D and technological advancements are required for this ubiquitous clean energy to get wider acceptance and employment. The future of this energy depends on the rational and scientifically sound exploration and use of the resources, just as in the case of fossil fuels, and thus precludes geothermal energy as a win-all solution to the energy needs of the whole world. • Computational analysis of geothermal energy research themes and linkages. • Algorithmic theme identification rather than expert-based analysis. • Tracing the key-routes of domain evolution. • Subdomain-specific status, limits, emerging fronts and future research agenda. • Impact analysis of contemporary technologies such as AI and 3D printing. [ABSTRACT FROM AUTHOR]

This is the first study utilizing carbon tax revenue to the renewable energy generation with Learning-by-doing (LBD) in the CGE model. This investigation demonstrates how induced technologically change (ITC) in the power sector offsets negative impacts on economic growth caused by the carbon tax in China. Business-as-usual scenario (without carbon tax) shows a significant impact of LBD on GDP growth and CO 2 emission reduction. Under a policy scenario with carbon tax, the results show that the negative impact on economic growth can be alleviated to less than 0.12%. If total carbon tax revenue was used for the subsidy to wind and solar power, even a positive impact on GDP growth will occur in the long-term. Therefore, the results verified and demonstrated the synergic effect of carbon pricing and the LBD process that economic loss caused by carbon tax could be offset by ITC in the renewable energy power sector. GDP decomposition shows that unexpensive electricity affected by ITC is beneficial to drive development of low-carbon energy, which can mitigate shock of carbon tax on heavy dependence on fossil fuel. This paper also provides policy implications that the LBD process will positively play a key role in energy structural shift under climate policy, making a great effort to climate mitigation. [Display omitted] • Combining bottom-up CGE model with top-down module Learning-by-Doing. • Utilizing carbon tax revenue to subsidy to renewable energy generation. • Providing optimistic impacts of carbon tax and subsidy on economic growth and reduction of carbon emission. • Learning-by-doing describes pathway of improved renewable energy. • Giving implication that Learning-by-doing can be boosted by environmental policies. [ABSTRACT FROM AUTHOR]

As a non-Arctic country and a major energy consumer, China is increasingly interested in participating in Arctic energy development. This study aims to investigate potential strategies to promote China's participation in Arctic energy development. Accordingly, this study analyzes the strengths, weaknesses, opportunities, and threats (SWOT) of China's participation in Arctic energy development based on a discussion of the current status of Arctic energy development and the Arctic policies of major countries. In addition, this work develops strategies in accordance with the above analysis. The results show that China has strengths in terms of capital, energy demand, policy support, and international cooperation when participating in Arctic energy development, while its weaknesses include the lack of core technology and equipment, high carbon intensity of energy development, and geographical disadvantage. China faces opportunities stemming from conflicts among Arctic states, the advancement of global carbon neutrality, and the development of Arctic waterway while facing threats such as increased competition, international public opinion pressure, high development costs, environmental risks, and pandemic instability. Under an integrated framework, this work offers four strategies: Strength-Opportunity (SO), Strength-Threat (ST), Weakness-Opportunity (WO), and Weakness-Threat (WT). Finally, this study proposes specific measures in four areas, including strengthening policy support, promoting technical research and development, enhancing international cooperation, and improving enterprise competitiveness. [Display omitted] • This study examines China's participation in Arctic energy development. • This paper reviews the status of fossil and non-fossil energy in the Arctic. • This study compares the Arctic energy development strategies of major countries. • This study proposes four strategies, namely SO, ST, WO, and WT. [ABSTRACT FROM AUTHOR]

The prosperity of microgrids and distributed energy resources (DER) promotes the standardization of multiple technologies. A sound and applicable standard system will facilitate the development of renewable energy and provide great guiding significance for technology globalization. As large-scale and high penetration DER integrate, the DER are performing a more active role to support the power distribution system operation, such as active\reactive power regulation and voltage\frequency control. Thus, various market stakeholders have paid enough attention to the technical dynamic change and regional difference at the level of microgrid standard and DER grid-integration standard, including AEPS (area electric power system) operators, AEPS owners, AEPS planners, AEPS designers, AEPS dispatchers, DER developers, DER owners, equipment manufacturers and regulators. However, existing literatures and researches are concentrated on technology innovation rather than the standards application. In our paper, we comprehensively review the standards development and current situation of microgrids and DER grid-integration issued by international organizations or individual countries. Then, based on technological knowledge iteration and engineering experience, the distinction of various standards is comprehensively compared from technical, geographical, and temporal aspectes. At last, the recommendation is provided for both standard maker and audience in the field of renewable technology to better formulate and apply standard. • The distinction of various standards is compared from technical, geographical, and temporal perspectives. • The dynamic change of standards is summarized at the level of DER grid-integration and microgrid level. • The recommendation is proposed for standard stakeholders, such as standard maker and standard audience. [ABSTRACT FROM AUTHOR]

The ocean is a huge energy conversion field, and ocean renewable energy (ORE) can provide us with a constant source of energy. Research on ORE collection and utilization has been emerging in recent years, and the number of ORE research results has been increasing. This paper visualizes the trends and current research status of ORE by performing bibliometric analysis using VOSviewer and CiteSpace. The results are analyzed in terms of annual publications, countries, institutions, authors, journals, keywords, topics, and references. The results indicate that current research hotspots include (1) theoretical calculations and simulation modeling, (2) design of ocean renewable energy devices (OREDs), (3) deployment of OREDs and optimization improvements, and (4) evaluation of ORE projects. Wave energy harvesting applications, offshore wind energy harvesting applications, design and improvement of triboelectric nanogenerator, and artificial reefs or islands are the frontiers of research in the field of ORE. With the development of energy conversion technologies, the future of ocean power generation will have a promising and attractive prospect. The results of the study provide a comprehensive overview of the evolution of research hotspots in this field and can help those researchers willing to work in this research area to quickly understand the research frontiers and the general situation. • Retrieved 3231 articles published over 10 years in the WOS core collection database. • Highlight top contributors, organizations, hot spots and research frontiers. • Classify key research topics and determine the knowledge structure related to marine renewable energy. • Looking for research frontiers and hotspots of marine renewable energy. • Evaluate research in this area and identify potential or possible future research areas. [ABSTRACT FROM AUTHOR]

The goal of carbon neutrality provides a new opportunity for the development of renewable energy, especially for wind power. In this paper, 11 regional climate models (RCMs) including CORDEX-EA and PRECIS at two different resolutions are used to evaluate the performance in simulating the spatio-temporal characteristics for wind speed and energy potential from 1981 to 2005. The results show that most models can reproduce the spatio-temporal patterns, and the simulation of the eastern region is better than that of the western region. Besides, most of the higher-resolution models had better simulation performance for spatial-temporal patterns and inter-annual variation. Then, the weighted multi-model ensemble is used to project the changes of the wind speed and the wind power density over China's mainland during the mid-21st century under the RCP8.5 scenario. In future, a decrease in wind speed is projected by most RCMs over China, although some regions, such as the southern parts of China, are projected to have more wind energy potential. The percentage variation of annual mean wind speed will remain in the range of ±4%. The wind power density will decrease in the north and the largest decrease will be found in the northwest. However, the annual mean wind power density in the southeast China will have an increase of 2.21% in the middle of this century. The inter-annual variation of the wind power density in most regions will increase by more than 20%. However, intra-annual variation in the wind power density is likely to decrease in most regions of China, ranging from about −20% to −50%. • A weighted multi-model ensemble was used to project the changes of wind power density over China. • The changes of annual mean wind power density vary in different sub-regions of China, ranging from −3.21% to 2.21%. • The inter-annual variation of the WPD in most regions will increase by more than 20%. [ABSTRACT FROM AUTHOR]

This Virtual Special Issue (VSI) contains some of the papers presented at the 23rd Conference of Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (PRES′20), which was virtually held in Xi'an, China on the 17 to 21 August 2020, related to the scope of Renewable and Sustainable Energy Reviews. The works are not limited to review articles; most of them have significant contributions to knowledge development for integration and optimisation for sustainable industrial processing within the circular economy. Topics covered in this VSI also includes studies on salt hydrate-based gas-solid thermochemical energy storage technology, hybrid battery optimisation, and energy recovery under thermal waste-to-energy. In addition, work on novel and effective passive cooling strategy for photovoltaic panels, integrated gasification combined cycle (IGCC) power generation systems, heat pumps optimisation in low-temperature waste heat recovery, utilisation of solar heating systems for low-temperature heat demand industries, and double reheat for thermal power generation are presented. The articles on the energy strategies towards the circular economy (CE) show the content of biomass supply chain optimisation, renewable energy system towards carbon emissions neutral, stable energy use strategies. Lastly, nexus thinking for sustainable development under COVID-19 assesses the energy and environmental performance of waste personal protective equipment treatment and the optimisation of the energy-water-waste nexus at the district level for regional sustainability. These achievements communicate the most significant and relevant critical thinking in renewable and sustainable energy research and development. • Virtual Special Issue PRES′20 Conference. • Integration and Optimisation for Sustainable Industrial Processing within the Circular Economy. • Salt hydrate-based gas-solid thermochemical energy storage, Hybrid battery, double reheat for thermal power generation. • Waste-to-energy, Passive cooling strategy for photovoltaic panels, integrated gasification combined cycle power generation systems. • Heat pumps optimisation in low-temperature waste heat recovery, solar systems for low-temperature heat demand industries. [ABSTRACT FROM AUTHOR]

This Virtual Special Issue (VSI) contains some of the papers presented at the 23rd Conference of Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (PRES′20), which was virtually held in Xi'an, China on the 17 to 21 August 2020, related to the scope of Renewable and Sustainable Energy Reviews. The works are not limited to review articles; most of them have significant contributions to knowledge development for integration and optimisation for sustainable industrial processing within the circular economy. Topics covered in this VSI also includes studies on salt hydrate-based gas-solid thermochemical energy storage technology, hybrid battery optimisation, and energy recovery under thermal waste-to-energy. In addition, work on novel and effective passive cooling strategy for photovoltaic panels, integrated gasification combined cycle (IGCC) power generation systems, heat pumps optimisation in low-temperature waste heat recovery, utilisation of solar heating systems for low-temperature heat demand industries, and double reheat for thermal power generation are presented. The articles on the energy strategies towards the circular economy (CE) show the content of biomass supply chain optimisation, renewable energy system towards carbon emissions neutral, stable energy use strategies. Lastly, nexus thinking for sustainable development under COVID-19 assesses the energy and environmental performance of waste personal protective equipment treatment and the optimisation of the energy-water-waste nexus at the district level for regional sustainability. These achievements communicate the most significant and relevant critical thinking in renewable and sustainable energy research and development. • Virtual Special Issue PRES′20 Conference. • Integration and Optimisation for Sustainable Industrial Processing within the Circular Economy. • Salt hydrate-based gas-solid thermochemical energy storage, Hybrid battery, double reheat for thermal power generation. • Waste-to-energy, Passive cooling strategy for photovoltaic panels, integrated gasification combined cycle power generation systems. • Heat pumps optimisation in low-temperature waste heat recovery, solar systems for low-temperature heat demand industries. [ABSTRACT FROM AUTHOR]

Meeting the energy goals of the European Union requires new ways of managing energy. Decentralized energy management, cross-commodity energy production and usage optimization are promising means. Future neighbourhoods will include multiple forms of energy such as electricity, heat, and cooling. According to our vision, the smart neighbourhoods, can optimize energy across different vectors by sharing resources in a controlled way. The first contribution of this paper is a comprehensive review on market, regulatory and technological status to support the transition towards distributed cross-commodity energy management with focus on Germany and Finland. Markets disruption could lead to more decentralized structures. Mechanisms therefore have been proposed, but mostly without sector integration. Clean Energy Package includes legislation that is supportive towards cross-commodity energy sharing solutions. Corresponding implementation in Germany and Finland may be successful in both countries even though it differs. Regarding technology, the article identifies required technical components (IoT, AI and blockchain) focusing on their support decentralized and cross-sector energy systems. Key components of IoT are wireless communication and interoperability middleware. AI provides key technologies for modelling and optimization of sector-integrated and distributed energy systems. Even if there has been lots of research, practical implementations are still lacking. Furthermore, many technical challenges still exist for blockchain based solutions in decentralized energy systems. Moreover, organizational, and legal responsibilities need to be clarified to support the adoption of blockchains in decentralized energy systems. Finally, the article gives recommendations regarding an increasing implementation of cross-commodity sharing and how it can contribute to the energy transition. • Giving an overview of cross-commodity energy sharing in Finland and Germany. • It is shown how recent energy market development support energy transition. • Comparing the regulatory framework for smart components in energy markets. • Combination of IoT, AI and Blockchain to enable decentralized energy markets. [ABSTRACT FROM AUTHOR]

Renewable energy plays a crucial role in both climate change mitigation and adaptation in highly climate-vulnerable nations such as Nepal. This paper reviews various types of renewable energy technologies and their status, potential for adoption, relationship to climate change, and mitigative and adaptive roles in Nepal. Nepal has installed micro-hydro projects, solar power, improved cooking stoves, biogas technology, improved water mills, and wind energy to mitigate and adapt to climate change. There is a growing potential for renewable energy development in Nepal, such as hydropower, solar, wind energy, biogas, and improved cooking stoves. Roughly 70% of Nepal's energy consumption is generated from traditional energy sources while renewable energy accounts for approximately three percent. The gradual increase in the use of renewable energy has reduced greenhouse gas emissions and enhanced carbon sequestration. By adopting renewable energy technologies, Nepal has reduced emissions by 221,129 tCO 2 e from 2017 to 2018. Nepal's second Nationally Determined Contribution targets a 15% increase in national energy use from renewables with a reduction of 23% of CO 2 emissions by 2030 using biogas and improved cooking systems. Furthermore, a significant increase in the adoption of renewable energy has become a pivotal strategy in adaptation to climate change in social, health, and economic sectors resulting in time savings, alternative income sources, improved health and educational status, local job opportunities, and the promotion of social capital. The benefits of adapting to climate change and mitigating CO 2 emissions via renewable energy are significant at the local, national, and international levels. This study recommends that the government of Nepal focus work on energy policy reviews to address local energy demand and climate change issues by utilizing renewable energy resources at the local level, which has global implications. • Suitable, potential renewable energy technologies in Nepal. • The relationship between energy and climate change. • Relevant data on energy and climate change in tables and figures. • Social, economic, and environmental benefits of renewable energy. • Climate change adaptation and mitigation via renewable energy. [ABSTRACT FROM AUTHOR]

Globally, there is increasing awareness that the implementation of 'waste to energy' technology is one of the best means to achieve sustainable energy development. The most popular approach is the conversion of organic-rich compounds into clean and renewable products by anaerobic digestion (AD). Biogas can be produced from agricultural residues, municipal/industrial biowastes, and sustainable biomass, especially materials that are locally available. However, in many cases, the methane yields obtained from the conventional AD process are regarded as having limited profitability. This paper summarizes the recent knowledge regarding the different strategies that are used to enhance AD efficiency and the methods to strengthen the existing incentives to overcome today's barriers to biogas production. Special attention was given to several approaches used to improve the biodegradability of organic matter and the methane potential of feedstocks, mainly codigestion and pretreatment of single/mixed substrates. The statistical analyses indicated enormous variability among biogas systems, thus, there is a need for unification of the methods applied for process control and the parameters used for the discussion of results. A synchronized methodology is also needed to understand the environmental advantages and drawbacks of selected utilization pathways in biogas production. Currently, the underestimated potential of AD is of growing interest, and pretreatment/codigestion can directly increase the effectiveness of this technology and lead to its optimization. Nonetheless, a proper evaluation of the environmental (e.g., sustainable biomass) and social (e.g., bioaerosol nuisance) aspects is also needed. [Display omitted] • Biogas production is receiving growing attention in the circular economy aspects. • Codigestion of organic wastes needs detailed evaluation. • Pretreatment of locally available biomass improves biogas production. • Unification of reported data in AD should be considered. [ABSTRACT FROM AUTHOR]

Over the coming years, the world is projected to witness an upsurge in "drop-in" aviation biofuel production as part of the renewable energy and bioeconomy developments. This paper presents a comprehensive review of the current status of biojet fuel development and uptake in global commercial aviation industry, including state-of-the-art certified technologies (i.e. Fischer-Tropsch (FT); hydroprocessed esters and fatty acids (HEFA); alcohol-to-jet (ATJ); and hydroprocessing of fermented sugars (HFS)); potential feedstock that can be deployed; a comparison of techno-economic and environmental performances of biojet fuel production routes; airlines' commitment in promoting higher biofuel uptake; and global initiatives and policies. This review shows that the HEFA route using oil-based crops is best performing in terms of lowest production cost and greenhouse gas emissions, however it is in competition with the existing road transport biofuel market. Lignocellulosic biomass and waste feedstock should be promoted in view of replacing food/feed crops which have high indirect land use change emissions. Therefore, further improvement should be focused on FT, ATJ and HFS routes to enhance the cost effectiveness of biojet fuel production and promote commercialisation of these technologies. The selection of feedstock and technologies for SAF production should be justified based on production cost and environmental footprint, while avoiding competition with the existing road transport biofuel market. The shortcomings in the SAF policies such as blending mandate and multiplier in RED II should be addressed to reduce the negative impacts of feedstock competition between the road and aviation biofuel sectors and to meet the decarbonisation targets. • Waste and residue feedstock should be deployed for biojet fuel production. • Non-oil based routes require further improvement on cost competitiveness. • Imposing a blending mandate is more effective than voluntary approach. • Multi-stakeholder collaboration promotes uptake of sustainable aviation fuel. [ABSTRACT FROM AUTHOR]

The composition of worldwide energy consumption is undergoing tremendous changes due to the consumption of non-renewable fossil energy and emerging global warming issues. Renewable energy is now the focus of energy development to replace traditional fossil energy. Energy storage system (ESS) is playing a vital role in power system operations for smoothing the intermittency of renewable energy generation and enhancing the system stability. We divide ESS technologies into five categories, mainly covering their development history, performance characteristics, and advanced materials. Biomass storage and gas storage are also discussed, which are not considered in most reviews. After detailed research, the rapid development of each technology in recent years is introduced, and some representative research works are surveyed. We comprehensively summarized the advantages and disadvantages of various ESS technologies and presented several evaluation indicators for quantitative analysis. Hybrid ESS is also considered based on the complex market demand. Then, we investigate the applications of various ESS technologies as short-term, medium-term, and long-term storages in power systems, covering the power generation, transmission and distribution, and end-user. Finally, this paper reviews global developing trends, and identifies critical challenges and promising opportunities. • Comprehensively review five types of energy storage technologies. • Introduce the performance features and advanced materials of diverse energy storages. • Investigate the applications of various energy storage technologies. [ABSTRACT FROM AUTHOR]

As the goal of carbon neutrality has been proposed consecutively, renewable energy sources such as wind, solar, and bioenergy are gaining close attention in national strategic and sustainable development plans. Along with the development of renewable energy generation technologies, it is necessary to assess the environmental burden of renewable energy generation. This study analyzed the economic and environmental benefits of wind power, solar power, and biomass power generation methods over their life cycle. This paper comprehensively assessed and compared their environmental impacts based on a life cycle assessment (LCA) framework combined with ecological footprint analysis for the three renewable energy generation in China, and compared the results with those of thermal power generation to make strategic suggestions for the renewable energy power generation industry. The results show that: (1) wind power consumed the least energy, only 6.80 kJ/kW·h, and had the lowest emissions of CO 2 , SO 2 , NOx and CO and environmental impact potential. (2) Based on the ecological footprint analysis on the provincial level, only Anhui, Shandong and Jiangsu provinces showed ecological deficits, while the other provinces were in ecological surplus, mostly above 50% of their ecological areas. (3) Compared to thermal power generation, which consumed 1170.911 kJ/kW·h, wind power was the only one of the three renewable energy achieved a reduction in energy consumption. Wind power is currently the most efficient way of generating renewable energy. [Display omitted] • The environmental and economic benefits of wind power, solar photovoltaic power, and biomass power generation were assessed. • Life cycle assessment and ecological footprint were used as analytical methods. • Wind power generation is preferred to solar photovoltaic and biomass power generation. • Recommendations for the future development of the renewable energy generation industry are presented. [ABSTRACT FROM AUTHOR]