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This paper is an Editorial for the special issue (SI) of Energy Reviews (RSER) dedicated to the 10th International Conference on Sustainable Energy and Environmental Protection SEEP, held in Bled-Slovenia. During the conference more than 300 papers were presented, around 25% of these papers were accepted for this special issue. Papers discussed different topics related to renewable energy, energy storage systems and some environmental issues related to transportation. During this conference Prof Olabi presented a keynote talk on the relation between circular economy and renewable energy, case studies about implementing this concept in Scotland were included in his presentation. This editorial will give a short description on the relation between circular economy and renewable energy, then it will be followed by addressing the accepted papers in this special issue. [ABSTRACT FROM AUTHOR]

In view of the climate crisis, the development and the path of growth and expansion of renewable energy systems is an urgent task, but must carried out with great care on environmental compatibility and protection. Renewable energy supply systems that are suitable for grid-bound heat supply, particularly in urban areas in Europe, are geothermal binary plants that provide power as well as power and heat. This paper will present studies whose objective was the assessment of hydrogeothermal power and heat generation in low-enthalpy regions from the environmental standpoint. The German Environment Agency published results of a network of studies conducted between 2008 and 2016 on the analysis of detailed and comprehensive environmental impacts of the geothermal energy generation in Germany and has continuously evaluated these findings. In this article, the results of the Life Cycle Assessment are discussed, taking into account all effects and material flows within the entire life cycle. Based on these balances, differing geothermal systems are compared to each other and to other renewable and fossil energy generation systems in order to assess the ecological advantages and disadvantages of these systems. Taking into account local environmental impacts as well a comprehensive ecologic evaluation of potential environmental and human health impacts becomes possible. The paper presents the results of a) the mass and energy fluxes of the process chain along the life cycle, and b) the local environmental impacts along the life cycle with regard to the environmental indicators of these cases. The focus is on the impact of site and plant parameters. Concluding, it can be summarised that geothermal power and heat generation is a very low-carbon technology and can contribute to a sustainable energy supply. Hydrogeothermal plants show a significantly low surface consumption, and environmental impacts are only locally relevant and technically controllable. Through the development of optimised overall concepts, geothermal based power and heat generation can achieve minimal environmental impacts in all areas. The combined heat and power generation from geothermal resources is by far the most environmentally and climate-friendly energy supply compared to all other regenerative and fossil systems. [ABSTRACT FROM AUTHOR]

Most commonly, hydropower operation focused on the economic and social benefits of the humankind, whereas neglecting the riverine ecosystem conservation. This conventional approach of operation led to the degradation of the riverine ecosystem. As research progressed, adoption of natural flow variability in the operation of reservoir gained momentum. Flow variability is a major driver of the healthy river ecosystem, whereby discharging a certain amount of water could potentially reduce the adverse effect of reservoirs and dams on the riverine ecosystem. On this preface, the study presented here constitutes a multi-objective optimisation model of cascade reservoirs to maximise the power generation while minimising the shortage of environmental flows considering five environmental management classes. This paper analyses the case studies for Liujiaping-Yumitan cascade reservoirs. The environmental flows regarding each environmental management classes were calculated using "Global Environmental Flow Calculator", the model was solved using an anon-dominated sorting genetic algorithm (NSGA-II). The NSGA-II helps to find Pareto optimal sets of solutions, NSGA-II, however, cannot be used solely for taking a comprehensive decision. Therefore, the Projection Pursuit Cluster (PPC) model has been used additionally for the optimal sequencing of the compromised optimal solutions. The maximum annual power production considering five environmental management classes were respectively: 1.121, 1.109, 1.103, 1.109, and 1.117 (x108 kWh) with environmental flows shortage of 2060.82, 616.497, 200.52, 28.88, and 0.004 (x104 m3) respectively. Findings resulted from this study, highlight the necessity for power production compromise for a better degree of environmental protection. In contrast, the environmental benefit is more important not only for the sustainable operation of the hydropower but also for fulfilling the universal needs of the riverine ecosystem. Therefore, the outcomes of this study can be a guideline for decision-makers to improve the comprehensive benefits of the Liujiaping-Yumitan cascade hydropower station along with the conservation of the environmental health of the river. Image 1 • NSGA-II algorithm is capable of providing reasonable trade-offs between hydropower production and e-flows. • For higher environmental management classes, the e-flows shortage increases. • Annual power production remains nearly the same in all environmental management classes. • More power generation must be compromised to increase the degree of environmental protection. • GEFC approach can be used only for preliminary planning and operation purposes. [ABSTRACT FROM AUTHOR]

Abstract The contemporary energy transition will be characterized by many sub-transitions in the next three decades. Oil and gas will continue to play a very important role coupled with renewable energy sources in an energy mix scenario. In this context, the authors of the present work developed a project, named RELife (Renewable Energy for a new Life of offshore platforms), with the main goal of develop a model for the reuse of offshore Oil & Gas platforms at end-of-life stage for the production of renewable energy. In this paper, by considering two types of platforms (4-legged platform with 3 or 4 production wells), various technical scenarios are studied and investigated and for each scenario also the environmental and economic feasibility is evaluated. In addition, all the sub-models are compared with a standard decommissioning process. The evaluations are made for both the Adriatic Sea and the North Sea, two geographic areas with different availabilities of renewable resources. In order to assess also the economic and environmental feasibility, a Discount Cash Flow Analysis and a Life Cycle Assessment of all the scenarios have been conducted. Highlights • A model for the reuse of offshore oil rigs at end-of-life stage for the production of renewable energy has been developed. • Various technical reuse scenarios have been investigated with the relative energy flows considering real data. • A Discount Cash Flow Analysis and a Life Cycle Assessment of all the scenarios have been conducted. • Cost competiveness and environmental impacts have been calculated. [ABSTRACT FROM AUTHOR]

A growing literature suggests that community owned renewable energy (CRE) projects have the potential to deliver a range of environmental and local socio-economic benefits. There is relatively little empirical evidence to substantiate this, with few systematic efforts to assess social and environmental impacts or to understand the context in which given impacts arise. In this paper, we review and conceptualise the local impacts commonly cited in the literature and dissect the empirical evidence currently available to support their occurrence. Having assessed the quality of evidence and pinpointed knowledge gaps, we draw on methodological literature to identify approaches necessary to improve our understanding of the local impacts of CRE and explore their patterns of occurrence. We find a lack of robust survey and statistical evidence across all the seven impact categories identified. Of the impacts identified, ‘empowerment’ and ‘access to affordable energy’ are found to be the least studied. In addition, several impacts are associated only with specific types of community energy projects. We argue that the paucity of consistent evidence for direct impacts associated with the development processes and direct outcomes of projects suggests that the most substantial local impacts result from medium to long term indirect project outcomes and the investment of project revenues in the local community. As such, collective funding pools and negotiation processes around their distribution towards private versus public goods play a crucial role in determining transformative local impacts of CRE. [ABSTRACT FROM AUTHOR]

This paper explores the performance of public spending on the renewable energy sector. A panel Data Envelopment Analysis is employed to obtain efficiency scores. The case study is Italy and its 21 regions that implemented a Regional Energy Plan between 2003 and 2010. The findings show that special statute regions and Southern regions perform best in terms of technical efficiency under variable return to scale (VRS). On the whole, Italy shows an increase in the energy efficiency. Based on the Simar-Wilson bootstrap approach, a post-DEA is also run. These results provide evidence that being a southern region has a positive effect on the level of efficiency. Real GDP and the number of graduates in technical and scientific disciplines have a positive impact on the efficiency of the public intervention on renewable energy. [ABSTRACT FROM AUTHOR]

• Site suitability assessments are at the heart of renewable energy planning. • A collaborative approach enables developing a fit for purpose decision-support tool. • Stakeholder-driven site suitability criteria supports transparent decisions. • The tool supports informed discussions and fosters consensus on deployment areas. • Data and technological limitations signal action areas for advancing practice. Competing land-use demands associated with planning for renewables is resulting in growing social and political challenges. Spatial decision-support tools are being developed and applied to tackle some of these challenges by facilitating systematic identification of suitable development sites based on technical, environmental and socio-economic criteria. Nevertheless, decision-support tools are often developed with limited input from stakeholders affecting participative and accountable planning and decision-making. This paper aims to address this shortcoming and foster greater transparency in the development of support tools for renewable energy planning, and thus in siting decisions. It present and discusses a stakeholder-driven approach to the co-creation of an online decision-support tool that attends to planning policy, technical considerations, environmental protection and social concerns influencing renewable energy planning decisions in Ireland. This bottom-up approach, easily transferable to other jurisdictions, fosters proactive expert input, awareness raising and greater comprehensibility and acceptance of siting decisions. It also enables developing an interface that responds to users' needs. The paper contributes to advancing renewable energy planning practice through effective and meaningful stakeholder engagement that supports transparent and accountable decisions from the outset. It also highlights ongoing data and technological shortcomings affecting the integration and operationalisation of stakeholders demands and needs, which signal priority areas of action to further advance the development of renewable energy decision-support tools. [ABSTRACT FROM AUTHOR]

Abstract: Since Taiwan imports more than 99% of energy supply from foreign countries, energy security has always been the first priority for government to formulate energy policy. The development of renewable energy not only contributes to the independence of energy supply, but also achieves benefits of economic development and environmental protection. Based upon information available to public, the present paper reassesses reserves of various renewable energies in Taiwan. The assessment includes seven kinds of renewable energies, namely, solar energy, wind power, biomass energy, wave energy, tidal energy, geothermal energy and hydropower, which are all commercialized and matured in terms of current technologies. Other renewable energies, which have not proven as matured as the aforementioned ones, are only assessed preliminarily in this paper, such as second generation of biomass, deep geothermal energy, the Kuroshio power generation and ocean thermal energy conversion. According to the estimation of this paper, the reserve of wind energy, up to 29.9kWh/d/p (i.e., kWh per day per person), is the largest one among seven kinds of renewable energies in Taiwan, followed by 24.27kWh/d/p of solar energy, 4.55kWh/d/p of biomass, 4.58kWh/d/p of ocean energy, 0.67kWh/d/p of geothermal energy and 16.79kWh/d/p of hydropower. If regarding biomass as a primary energy, and assuming 40% being the average efficiency to convert primary energy into electricity, the total power of the seven kinds of renewable energy reserves is about 78.03kWh/d/p, which is equal to 2.75 times of 28.35kWh/d/p of national power generation in 2008. If the reserves of 54.93kWh/d/p estimated from other four kinds of renewable energies that have not technically matured yet are also taken into account, it will result that the reserves of renewable energy in Taiwan can be quite abundant. Although the results of the assessment point out that Taiwan has abundant renewable energy resources, the four inherent shortcomings – low energy density, high cost of power generation, instability of power supply, and current cost of renewable energy being still higher than that of fossil energy – have to be overcome first, before renewable energy is actually formed as a main component in national energy mix. The measures executed by government to break through these barriers further include the upgrade of the technological level, the formulation of the necessary policies, and the work together from all levels for the overall promotion. [Copyright &y& Elsevier]

The focus of this study is to show that by understanding the food-energy-water nexus, potential unforeseen negative outcomes can be avoided in the pursuit of sustainable development. To do this, this paper uses a novel approach to compare a combined farm and short rotation coppice willow system, in which the willow was planted as a riparian buffer, with a food-only and an energy only system. The impact of each system was investigated through the lens of the food-energy-water nexus using life cycle assessment techniques. Data from previous research was adapted in order to quantify the impacts for a typical Irish dairy farm, which is indicative of intensive agriculture across Europe. On a typical Irish dairy farm, the implementation of a short rotation coppice willow riparian buffer strip could reduce total nitrogen and phosphorus leachate by 14% and 9% respectively. Total CO 2 eq emissions could be reduced by 16.5% if energy from the willow displaces fossil fuels, while the impact on milk production and profit is minimal. Thus, the use of short rotation coppice willow as a riparian buffer strip has the potential to reduce strain on the entire food-energy-water nexus. By considering the food-energy-water nexus, the negative impacts of the food-only and energy-only systems were also highlighted. The paper also shows how a better understanding of the food-energy-water nexus supports the United Nations Sustainable Development Goals and could help ameliorate the impact of climate change on the food-energy-water ecosystem. Image 1 • Understanding the FEW nexus supports the UN Sustainable Development Goals. • Negative outcomes can be avoided by assessing systems using the lens of the FEW nexus. • SRC willow riparian buffer strips can complement agricultural intensification. • Nitrogen (−14%) and phosphorus (−9%) exports to water can be permanently reduced. • Agricultural GHG emissions can be reduced by 16.5%. [ABSTRACT FROM AUTHOR]

Abstract: In an effort to diversify economies and reduce high oil dependency, the Gulf Cooperation Council (GCC) countries plan to increase the use of renewable energy sources to meet the challenges of a post-oil future. The Accession to the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol, which require a commitment to reduce greenhouse gas emissions, has started a process of environmental awakening in the GCC countries. This paper reviews the publications on renewable energy with reference to the GCC countries since 2005. The objective was to investigate the benefits of funding and investing in renewable energy projects in the GCC countries. The article shows that the GCC countries have begun to adopt a more pro-active approach toward renewable energy that will help progress the GCC countries towards sustainability. The reorientation of strategies and policies toward renewable energy is evolving in the GCC countries. [Copyright &y& Elsevier]

Abstract: Currently, around 90% of Malaysia's electricity generation depends on fossil fuels. This reliance, in a long run, is not a secure option. However, renewable energy sources can contribute to a sustainable electricity generation system; but diversifying fuel supply chain is a complex process. Therefore, the aim of this paper is two folds. Firstly, various renewable resources potential are reviewed, and secondly an assessment model is developed for prioritizing renewable options. Four major resources, hydropower, solar, wind, biomass (including biogas and municipal solid waste) are considered. Their electricity generation potential, along with any likely shortcoming is also discussed. Moreover, using a multi-perspective approach based on analytic hierarchy process (AHP), an assessment model is developed. AHP model employs four main criteria, technical, economical, social and environmental aspects, and twelve sub-criteria. From the review it was found that renewable resources seem to have a sufficient potential to develop a sustainable electricity system. Furthermore, AHP model prioritize those resources, revealing that solar is the most favorable resource followed by biomass. Hydropower and wind however, are ranked third and fourth, respectively. The model also shows that each resource is inclined towards a particular criterion; solar towards economical, biomass towards social, hydropower towards technical, and wind towards environmental aspect. Besides reporting AHP model for the first time in Malaysian context, the assessment performed in this study, can serve decision makers to formulate long-term energy policy aiming for sustainability. [Copyright &y& Elsevier]

The current editorial summarized some of the scientific works presented in the Sustainable Energy and Environmental Protection (SEEP) conference-held at the University of the West of Scotland, UK, 2018. The selected work was directly related to the scope of the Renewable, Sustainable Energy Reviews (RSER) journal. During the conference activities, experts from all around the world in the subjects of: renewable energy, climate change, optimization, and economics presented and discussed the progress made in renewable energy sources, as well as the new strategies for protecting the environment from the hazards connected with fossil fuel utilization. The methods presented in the conference focused on several directions: the development of efficient energy conversion systems with low/no environmental impacts; the suggested policies to widespread renewable energies; the restriction in the emission of greenhouse gases, and the recent progresses in CO 2 capture. This editorial focused on the renewable energy developments and their positive effect on the climate change, and briefly summarized the accepted manuscripts in this issue. • Effects of renewable energy on climate change. • Background on the International Conference on Sustainable Energy and Environmental Protection SEEP. • Summary of selected papers of SEEP 2018. [ABSTRACT FROM AUTHOR]

The current editorial summarized some of the scientific works presented in the Sustainable Energy and Environmental Protection (SEEP) conference-held at the University of the West of Scotland, UK, 2018. The selected work was directly related to the scope of the Renewable, Sustainable Energy Reviews (RSER) journal. During the conference activities, experts from all around the world in the subjects of: renewable energy, climate change, optimization, and economics presented and discussed the progress made in renewable energy sources, as well as the new strategies for protecting the environment from the hazards connected with fossil fuel utilization. The methods presented in the conference focused on several directions: the development of efficient energy conversion systems with low/no environmental impacts; the suggested policies to widespread renewable energies; the restriction in the emission of greenhouse gases, and the recent progresses in CO 2 capture. This editorial focused on the renewable energy developments and their positive effect on the climate change, and briefly summarized the accepted manuscripts in this issue. • Effects of renewable energy on climate change. • Background on the International Conference on Sustainable Energy and Environmental Protection SEEP. • Summary of selected papers of SEEP 2018. [ABSTRACT FROM AUTHOR]

Abstract: Nowadays, China is faced with many issues, such as increasing farmers’ income, protecting environment and adjusting energy structure, which may be solved by developing the biomass power generation industry. However, the lack of technical capability, inadequate raw materials and challenges for grid feed-in are all obstacles that prevent large-scale production and industrialization in the biomass power generation industry. Therefore, government should provide necessary policies to support and advance the biomass power generation industry. This paper systematically analyzes the current laws, regulations and policies implemented recently in China and provides a comprehensive review of the fiscal subsidies, reduction and exemption of taxes, tariff concessions, the policies of investment and financing and the support of R&D. Suggestions for relevant policies are proposed to address the existing problems. [Copyright &y& Elsevier]

Abstract: This paper aims to present Malaysia''s green developments, focusing on the National Green Technology Policy and Green Building Index which have been introduced since 2009. Various green initiatives and their progresses to date will be discussed as well as the key implementing green agencies. The benefits of going green to the country and incentives being offered by the Malaysian Government are also presented. The prospect of a green future in Malaysia, spurred by the worldwide outlook towards sustainable development and environmental preservation is very bright. Pursuing green technology in economic and social developments not only helps sustain the non-renewable fuels, safeguards and minimises the environmental degradation due to carbon emissions, it also creates a strong green economy and industry, inline with the country''s vision as well as the rest of the world economies. [Copyright &y& Elsevier]

Abstract: With the largest population living in rural areas, the lack of clean energy supply is an important problem in China, and the utilization of renewable energy not only meets the demand of energy, but also provides a basis for environmental protection and sustainable development. This paper reviews use of clean energy in a resource-rich region, including the basic principle of the development of recycling agriculture, the potential, the present status and the future of renewable energy in the region rural areas. If the project will be finished, there will be 300,000 families benefiting from it and it can bring at least 2.2×108 US dollars revenue increase directly, the indirect revenue increase will be 0.15billion US dollars, the environment will be improved and the living standard in Jincheng''s rural areas is also be greatly improved because of developing biogas project. Based on the developing status and constraint conditions, the solutions to further promote renewable energy projects in this region are also proposed. [Copyright &y& Elsevier]

• First comprehensive review on two-phase loop thermosyphon technology. • Characteristics, mechanism, and research progress of two-phase loop thermosyphon. • Independent two-phase loop thermosyphon for effective heat transfer. • Novel integration and coupling with vapour compression cycle. • Challenges and prospects of two-phase loop thermosyphon technology. Two-phase loop thermosyphon is a natural phase-change heat transfer cycle widely used for thermodynamic applications. In additon to low manufacturing and maintenance costs, the primary advantages of such device include high heat transfer capability, reliability, and sustainability. Significant progress has been made in the two-phase loop thermosyphon and its integrated/coupled systems for energy conservation and environment protection. This paper represents a comprehensive review that discusses the physical mechanisms, characteristics and research progress of the two-phase loop thermosyphon based on recent experimental and simulative studies. The review extends to worldwide applications of independent two-phase loop thermosyphon in the renewable and sustainable energy fields and its utilisation for performance enhancement of vapour compression cycles by system integration and coupling. Challenges and recommendations for future research and application of two-phase loop thermosyphon are identified. This review will help researchers and engineers better understand the mechanisms, features and potential of the two-phase loop thermosyphon technology and promote its development. [ABSTRACT FROM AUTHOR]