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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]

Under the banner of the United Nations' Sustainable Development Goal 7 (SDG 7), governments, industry, and civil society organisations have supported many energy access projects since 2015. Notably, funding and investments allotted to renewable energy are regarded not only to provide 'energy for all' but also support the delivery of other SDGs related to climate change, food security, health, and poverty reduction, among others. With less than 10 years left to meet the SDG 7 targets, it is timely to take stock and examine how the provision of access to energy is driving development initiatives, impacting local communities, and influencing governance processes. This paper offers a critical review and analysis of the impact of access to energy projects based on empirical work from eight country case studies across Africa, Asia, and Latin America. It interrogates how these projects contribute towards achieving SDG 7 and other sustainable development goals, highlights challenges, and then draws lessons for research, policy, and development practice. To advance SDGs, it recommends action in four areas: addressing rural-urban disparities, ensuring that energy is linked to sustainable outcomes, balancing top-down and bottom-up agendas, and appraising implications of techno-economic factors. [Display omitted] • Energy access has been constrained by multiple factors outside of policy decisions. • Governance decisions have overlooked local actors who are key to project sustainability. • Improved efficiency is more vital to energy security and access than increased generation. • Alignment between policies, governance processes, and institutional commitments is crucial. [ABSTRACT FROM AUTHOR]

Over the last two decades, the world has experienced a boom in the number of hydropower projects. Considered an important part of sustainable development, particularly in post-socialist transition and developing countries, it is claimed that hydropower plants will make substantial contributions to environmentally friendly economic growth and poverty eradication. However, the so-called 'hydropower boom' has not resulted in a global mass construction of plants. In general, over-ambitious planning, a lack of funding opportunities and corruption are often put forward as explanations for the discrepancy between the number of plans and actual construction of hydropower plants. In this paper, it is added to these three reasons, illustrating with a case study from Bosnia and Herzegovina, where the planning of hydropower projects very rarely results in their construction. The results are based on secondary data and primary data, i.e. semi-structured interviews and informal talks, collected during fieldwork in Bosnia and Herzegovina. The data was analyzed using the analytical induction method. The results highlight how administrative complexity, over-estimations of exploitable capacity, an unattractive sociopolitical and socioeconomic situation and how these factors in combination create the conditions for various practices of corruption hinder the construction of plants. Comparing the results with other findings from around the world, the paper suggests approaching the so-called global hydropower boom with caution. • Over-ambitious planning results in an unrealistic number of planned project. • Lack of funding opportunities hinders the actual construction of the projects. • Prevalent corruption result in projects being revoked or remaining on paper. [ABSTRACT FROM AUTHOR]

High-value utilization of plant resources is crucial for achieving carbon neutrality and complete carbon transformation. Significant progress has already been made in the comprehensive utilization of plant resources through pretreatment methods, particularly the deep eutectic solvent (DES) method for the pretreatment of plant fibers. This method enables sustainable development of lignocellulose deconstruction and high-value utilization. This paper provided a review of the composition, classification, and properties of different types of DES. It also investigated the effects of stoichiometric ratio, temperature, time, microwave, ultrasonic, hydrothermal, and emulsification on lignocellulose deconstruction using the DES. Additionally, the study explored the use and prospects of lignocellulosic fractions in lignin extraction, enzymatic saccharification, and high-value cellulose production using functional DES systems. The evaluation of the DES functionality is conducted through quantum chemistry, molecular simulation calculations, and the DES recycling effects (optimum 10 cycles). The mechanism of DES in lignocellulosic extraction is elucidated, and the prospects for sustainable development are outlined. • DES is capable of deconstructing lignocellulose to achieve high-value plant resources. • The progress of the functional and specific application of DES for lignocellulosic pretreatment has been discussed. • Summary of the evaluation system for the DES functional system and method for the DES pretreated lignocellulose. • Prospects for the future development of the DES system in the field of plant resource extraction. [ABSTRACT FROM AUTHOR]

Virtual power plants possess the capability to effectively manage the inherent conflict between dispersed electricity generation and user demand, hence optimising market advantages. Nevertheless, the presence of severe weather conditions, geopolitical factors, the phenomenon of global warming, and several other global concerns greatly enhance the level of uncertainty related to the establishment of sustainable energy sources and the corresponding demand from users. Consequently, these factors expose the limitations of virtual power plants in effectively controlling power supply. The active involvement of community members has the potential to invigorate the process of development. This study presents a novel model, referred to as the CE-based cVPP (CE-cVPP) model, that combines the principles of circular economy (CE) and community-based virtual power plant (cVPP). The objective of this model is to enhance the effectiveness of sustainable development efforts. This research redefines the concept of a CE-cVPP, elucidates its defining features, scopes, and classification, and constructs a technological framework, together with an explanatory community case structure. The CE-cVPP energy life cycle framework is constructed based on the principles of the circular economy paradigm. This study investigates the enduring and sustainable benefits of the CE-cVPP across four dimensions: energy, environment, economics, and society. In conclusion, this paper provides a comprehensive examination of the energy, digital, and circular economy perspectives, encompassing critical analysis, problems, prospective analysis, and future directions. • Circular economy and community-based Virtual Power Plant (CE-cVPP) is a paradigm for the future energy sector. • CE-cVPP is a novel sustainable pattern that combines circular economy and community virtual power plants. • CE-cVPP features renewable energy, electricity, gas, cold, heat, and biodegradable waste. • CE-cVPP promotes economic, social, and ecological sustainability. • CE-cVPPs enhance the power and energy system's adaptability, versatility, and stability. [ABSTRACT FROM AUTHOR]

Abstract This paper is an Editorial for the special issue (SI) of Renewable and Sustainable Energy Reviews (RSER) devoted to the 12th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES), held from the 4th to 8th October 2017 in Dubrovnik, Croatia. The key focus of RSER is to publish critical thinking across the wide field of renewable and sustainable energy. The journal publishes either pure review papers or research papers with a precise review element. Overall, the guest editors invited 36 papers presented on 12th SDEWES conference, of which 17 were accepted after rigorous peer review process. The SDEWES conferences present a continuous effort in gathering high level scientists and research papers across the field of sustainability and by now the amount of accumulated knowledge, through conference papers and special journal issues, is significant. Each SDEWES journal editorial presents a wider overview of special issue journal papers in order to maintain the continuation of knowledge generation on the main sustainability topics. The main topics covered in this RSER editorial include renewable energies with special focus on integration, markets and roadmaps, energy efficiency in buildings, industrial process and transport, bio based economy focused on bio based chemicals and biofuels, energy storage focused on batteries, thermal and geological storages and various sustainability assessments in several sectors and technologies. All were considered in light of the Circular Economy. [ABSTRACT FROM AUTHOR]

Abstract While auctions are becoming increasingly popular for tendering renewable energy projects to private developers in Africa, their specific project risk implications are not yet fully understood. This paper identifies project risks arising from two types of auction schemes. It compares an approach where the government pre-selects the sites for future renewable energy plants in Zambia's Scaling Solar initiative to one where project developers choose, secure and conduct due diligence on their sites before bidding in South Africa's Africa's Renewable Energy Independent Power Producers Procurement Programme (REI4P). Semi-structured interviews with developers who have participated in both schemes reveal notably different risk profiles. Despite contrary intentions, site-specific risks have been perceived as the highest overall project risk in the government-led site selection process in Zambia. Specifically, site-specific risks were driven by several severe technical issues such as geotechnical, grid connection and solar irradiation uncertainties. In contrast, in South Africa's developer-led site selection process, site-specific risks have been reported to be important, but less pronounced, and more evenly distributed among technical, economic, legal, permitting and social risk factors. This paper recommends an auction design which minimises project risks for all stakeholders. Where governments pre-select sites, closely consulting the private sector is advisable prior to bidding to identify and mitigate technical and other site-specific risks. Highlights • Explores risk impact of two site selection & preparation strategies for solar PV project procurement in sub-Saharan Africa. • The widely used strategy in the region is for a government institution or utility to select and prepare the project site. • The second strategy is where the private sector developers are responsible for selecting & preparing the site before bidding. • We find that a government-led site selection strategy can lead to increase risks, costs and timelines if poorly executed. • It is argued that more private sector involvement in the site selection & preparation process might reduce these risks. [ABSTRACT FROM AUTHOR]

Abstract The energy consumption in buildings accounts for a significant proportion of total energy and carbon emissions over the world. To reduce the building energy consumption and achieve sustainable development of buildings, nearly zero energy buildings (NZEBs) have attracted widespread attention as a future building energy target. This paper reviews energy-efficient measures (EEMs) and renewable energy technologies (RETs) in NZEBs and discusses the application and suitability of the key technologies, i.e. minimizing the energy demand in NZEBs by EEMs and adopting RETs to meet the remaining energy needs. EEMs contain efficient thermal insulation system, high-performance window system, good airtightness and fresh air heat recovery system. RETs are composed of solar photovoltaic/thermal (PV/T) system, air source heat pump system (ASHP), ground source heat pump system (GSHP), and wind power. In addition, this paper emphasizes further research works, which involve life cycle energy analysis (LCEA), meteorological parameters change, intelligent building operation management (IBOM) system, energy storage system and social policy issues. This paper will provide some references for the further development of NZEBs in different climatic regions in China. Highlights • This paper systematically reviews application of EEMs and RETs in NZEBs in China. • Feasibility and suitability of EEMs and RETs are evaluated from different aspects. • Further research work and development direction of NZEBs are pointed out. [ABSTRACT FROM AUTHOR]

Existing pieces of literature on previous studies advocate the research focus by various researchers to reach the benchmark of energy efficiency of Wastewater Treatment Plants (WWTPs). The driving factors to improve the energy efficiency and mitigate the energy self-sufficiency of WWTP have been identified as the increase in population growth, rising energy costs, and tightening effluent discharge requirements. WWTP economy is directly related to energy consumption and thus affects smart grid economy. There has been limited research on energy self-sufficiency and optimizing the energy demand and cost of WWTP, where the significant contributing factors are in development an optimal pumping system and advanced motor technologies. Moreover, high quality WWTP's effluent depends on the concentration level of biochemical oxygen demand (BOD) and total kjedhal nitrogen (TKN). Even so, WWTPs are always subject to evident nonlinearities and uncertainties, making it difficult to define proper optimization objectives. Besides, controllers and control systems have a strong influence on the performance of the plants. Therefore, existing research gaps to achieve optimal efficiency with minimized energy consumption and costs are the design of the WWTP plant, pumping system, motors, selection of suitable controllers and control systems, and their parameter optimizations to get the optimal output from the plant, switching techniques, challenges and uncertainties associated with plant are highlighted in this paper. Thus, as a novel contribution to the literature, this study aims to review and analyze the history, current issues, and future directions of WWTP control technologies in the context of sustainable development. The rigorous study by the authors in this paper will definitely lead the academic researchers and industry partners toward the development of optimal WWTP technologies with improved efficiency and minimized energy consumption and costs. • Effective control techniques and monitoring of the wastewater treatment plant. • Optimal energy-efficient WWTPs with renewable sources and the utility grid. • Uncertainties of WWTP can be considered for improved operation. • Effective policies should be imposed by combining academics and industry. • Reduced energy consumption and cost can be achieved. [ABSTRACT FROM AUTHOR]

Solar energy offers over 2,945,926 TWh/year of global Concentrating Solar Power (CSP) potential, that can be used to substitute fossil fuels in power generation and mitigate 2.1 GtCO 2 of greenhouse gas (GHG) emission to support Sustainable Development Goals (SDGs) set by the United Nations (UN). Thermal energy storage (TES) is required in CSP plants to improve dispatchability, reliability, efficiency, and economy. Of all TES options, the latent heat thermal energy storage (LHTES) together with phase change materials (PCMs) exhibit the highest potential in terms of efficiency and economy. PCM properties thus become the ultimate decider of CSP performance. This paper reviews over 200 of published articles and websites to describe the history, identify the technologies, economics, and current trends of PCM as LHTES material for CSP plants. A list of 163 PCM candidates suitable for LHTES systems in low-temperature (T < 220 °C), medium-temperature (220 °C < T < 420 °C), and high-temperature (T > 420 °C) applications is presented for the first time. Research gaps are identified to determine the future directions. • CSP shows remarkable potential in global electricity generation. • Intermittency of solar has made the requirement of a TES for CSP system. • We evaluate the advantages of LHTES for storing thermal energy. • LHTES shows 5–14 times the energy density of SHTES allowing for more compact storage and lower inventory requirements. • Selection of a compatible PCM is crucial for operating the LHTES at desired performance level. [ABSTRACT FROM AUTHOR]

Capture and sequestration of CO 2 released by conventional fossil fuel combustion is an urgent need to mitigate global warming. In this work, main CO 2 capture and sequestration (CCS) systems are reviewed, with the focus on their integration with renewables in order to achieve power plants with nearly zero CO 2 emissions. Among these technologies under development, the Dry Carbonate Process shows several advantages. This manuscript analyses the integration of a CO 2 sorption-desorption cycle based on Na 2 CO 3 /NaHCO 3 into a coal fired power plant (CFPP) for CO 2 capture with solar support for sorbent regeneration. The Dry Carbonate Process relies on the use of a dry regenerable sorbent such as sodium carbonate (Na 2 CO 3 ) to remove CO 2 from flue gases. Na 2 CO 3 is converted to sodium bicarbonate (NaHCO 3 ) through reaction with CO 2 and water steam. Na 2 CO 3 is regenerated when NaHCO 3 is heated, which yields a gas stream mostly containing CO 2 and H 2 O. Condensation of H 2 O produces a pure CO 2 stream suitable for its subsequent use or compression and sequestration. In this paper, the application of the Dry Carbonate CO 2 capture process in a coal-based power plant is studied with the goal of optimizing CO 2 capture efficiency, heat and power requirements. Integration of this CO 2 capture process requires an additional heat supply which would reduce the global power plant efficiency by around 9–10%. Dry Carbonate Process has the advantage compared with other CCS technologies that requires a relatively low temperature for sorbent regeneration (< 200 °C). It allows an effective integration of medium temperature solar thermal power to assist NaHCO 3 decarbonation. This integration reduces the global system efficiency drop to the consumption associated with mechanical parasitic consumption, resulting in a fossil fuel energy penalty of 3–4% (including CO 2 compression). The paper shows the viability of the concept through economic analyses under different scenarios. The results suggest the interest of advancing in this Solar-CCS integrated concept, which shows favourable outputs compared to other CCS technologies. [ABSTRACT FROM AUTHOR]

Jurisdictions around the world are responding the to potential of smart grids in different ways. This paper employs a multi-level perspective approach to socio-technological transitions to examine why the Canadian province of Ontario has seen a relatively smooth transition of smart meter technologies from the niche to regime levels as compared with other Canadian provinces, and other jurisdictions in the United States, European Union, and Australia. The paper also examines the reasons for Ontario's advanced legislative and policy framework around Smart Grid development, relative to those of other provinces. The complex institutional landscape around electricity that has emerged in Ontario since the break-up of the province's monopoly utility Ontario Hydro in the late 1990s emerges as a significant factor in both outcomes. The role of the province's municipally-owned LDCs spell out "local distribution companies (LDCs) as the primary agents for smart meter deployment, as opposed to a dominant vertically integrated utility, appears to have had an important mediating effect on public opposition to smart meters. With respect to Smart Grid policy, the diversity of high capacity institutional actors that now define the province's electricity policy landscape has facilitated the emergence of several interagency policy development niches. In a manner consistent with the concept of technological niches in the socio-technical transitions literature, the interagency status of these policy niches has shielded them from the regime level selective pressures that would likely have existed in a more unified institutional structure, and empowered new policy ideas to move from the niche to regime levels. These outcomes have significant implications for the understanding of socio-technological transitions, particularly around the role of institutional complexity in the emergence of niches for technology and policy development purposes and in niche to regime level transitions. [ABSTRACT FROM AUTHOR]

Sustainable construction is the only way to ensure the implementation of the principles of sustainable development. The paper presents the importance of the thermal insulating investment of the building in three areas: economic, environmental and social. It shows the influence of the existence of the building on the environment, with a particular focus on the investment process involving thermal insulating of external vertical walls of the building. The paper proposes a methodology for assessing the environmental and economic benefits. The analyses for various combinations were performed, including the condition of the building before thermal insulation, type of construction material of the building, the heat source used, type of thermal insulation and climate zone, in which the building is located. The obtained results indicate that the thermal insulation investment is, for all examined variants, beneficial for ecological reasons and for almost all economic reasons. The highest values of economic benefits were obtained for the variant of the coldest climate, and the variant in which the building before thermal insulation has the worst thermal performance, the most expensive type of heat source (i.e. the biggest costs of obtaining 1 kWh of thermal energy) and the least expensive material used for thermal insulation. The highest values of environmental benefits were obtained for the variant of the coldest climate, which is obvious, but also for the variant, in which the building before thermal insulation has the worst thermal insulation, the least environmentally friendly type of heat source and the most eco-friendly insulation material applied. The paper also articulates social benefits resulting from such an investment. [ABSTRACT FROM AUTHOR]

Efforts to deal with anthropogenic environmental impacts are focussed predominantly on cities. This paper applies metafrontier-data envelopment analysis (DEA) to evaluate the capacity of 286 Chinese cities of different sizes and in different regions towards green growth development and assesses gaps in their efficiencies. The determinants of efficiency, including regional and population size effects, were estimated using logistic regression model. Results show that the state of green growth efficiency was different for cities of different sizes and from different regions, and gaps existed compared to the best production frontier. The paper suggests that more endeavours are required for environmental and social dimensions, and a short-term target can include achievement of group frontier efficiency and significant reduction in technology gap ratios. Owing to significant population size effect, policy programs should have target plans for cities of different sizes as they differ in performance and capacity building. [ABSTRACT FROM AUTHOR]

As an important energy base of China, Xinjiang is the key part of the “Silk Road” economic belt development strategy and is in an superior position. This paper analyzes the problems exist in the sustainable energy industry based on the distribution status of sustainable resources of Xinjiang. The evaluation index system of the application level of Renewable Energy Systems (RESs) is discussed using the wind farm as an example. Besides it investigates the advantages and disadvantages of the development process of each node in the “Silk Road” economic belt areas according to the current situation of the resources, economic and social development. Suggestions for the development of each area are proposed in the end. This paper will contribute to the sustainable development of renewable energy industry and economy in Xinjiang. [ABSTRACT FROM AUTHOR]

Water and energy are the key drivers of agricultural production while the world is facing severe energy and water crisis. Increasing crop production per unit area for the increasing population of the world is dire need of time. Thus, sustainable approaches are required to ensure food security and energy security. One of the sustainable development approach is solar photovoltaic water pumping system (SPVWPS). It is a promising alternative to the conventional pumping systems and a cost-effective application especially in remote off-grid areas of developing countries. In recent years, through continuous improvement, the photovoltaic pump system has been widely used in agricultural, industrial, and domestic sectors. Present paper intends to review and summarize the recent research and development performed in SPVWPS. The study focuses on components of the photovoltaic pump system, factors affecting system efficiency, performance assessment, optimization of the system, and possibility of combination with other green technologies. An update on the research and current situation of SPVWPS is presented. SPVWPS is found to be feasible in comparison to the conventional pumping systems. Application of PV pumping in different regions of the world are also discussed. This paper aims to provide a broad outlook on SPVWPS for the researchers, engineers, manufacturers, and policy makers. [ABSTRACT FROM AUTHOR]

Global anthropogenic activities resulting in the emission of harmful greenhouse gases (GHGs) to the atmosphere have increased the challenges faced from climate change. The greater awareness of the need to mitigate climate variability has brought about intense focus on the adverse impacts of fossil-fuel based energy on the environment. Being the single largest source of carbon emissions, energy supply has attracted much attention and more so that, climate change impacts extend beyond national boundaries. Since energy use is sine qua non to economic development, scientists have reiterated the necessity of developing and utilising renewable energy. Although, past and present CO 2 emissions have and are majorly caused by industrialized countries, it is envisaged that future GHGs emissions would be mostly from developing countries as they industrialize. Renewable energy sources that include biomass, hydroelectric, wind, solar and hydrothermal systems, are carbon-neutral, releasing relatively no emissions. This paper discusses the initiatives associated with the provision of renewable energy to the energy mix in Nigeria as an indication of the country’s commitment to adopt a sustainable development strategy in shaping the economy. It reviews the literature and employs a discourse analysis to examine the limited use of renewable energy sources in Nigeria and the factors prevailing against their development. The paper concludes by identifying social and political obstacles as most significant roadblocks towards rapid implementation of a green economy through the deployment of renewable energy for sustainable development. [ABSTRACT FROM AUTHOR]

Energy demand in China has risen rapidly and reached an unprecedented level due to the high-speed economic growth and modern development. As a result, the Chinese government faces a growing pressure to address the energy shortage and environmental deterioration, mainly resulting from an over-dependence on fossil energy. China has become both the largest energy consumer and CO 2 emitting country in the world in 2015. Utilization of potential for renewable energy is necessary for changing inappropriate energy consumption structure, protecting environment and achieving sustainable economic and social development. In view of such mentioned situation, this paper firstly introduces the energy structure as well as the development status of renewable energy in China, which includes hydropower, wind power, solar power, biomass power and other renewable energy. Besides, based on the current situation in China, the paper makes a preliminary prediction of the development of renewable energy in the country for the future decades, and proposes targeted countermeasures and suggestions. [ABSTRACT FROM AUTHOR]

This paper reviews methods that measure mineral resource depletion based on cumulative exergy consumption approaches. It focuses on the exergy replacement cost (ERC), which measures the amount of exergy society would have to consume in order to re-concentrate an extracted and processed mineral to the point that it can be once more exploited by future generations. The ERC, which was originally only suitable for non-fuel minerals, was adapted and extended in 2016, by changing the focus of the ERC from the chemical composition of the resource to its function, to include fossil fuel depletion. This paper discusses the impact of these new developments and identifies conceptual and methodological weaknesses that need to be addressed for the ERC to find widespread use in exergy analysis and in order to assess the sustainability of mineral policy from the grave to the cradle. [ABSTRACT FROM AUTHOR]

Europe has a large tradition of Small Hydropower stations (SHP); these proliferate wherever there was an adequate supply of moving water and a need for electricity. As electricity demand grew many of these plants were abandoned. Today with the rising price of energy, SHP can be a solution to help rural electrification, furthermore SHPs do not consume the water that drives the turbines. The advantage of this technology is extremely robust and systems can last for 50 years or more with little maintenance. This paper summarizes an overview of SHP Hydropower in Europe. Hydropower on a small scale, or micro-hydro, is one of the most cost effective energy technologies to be considered for rural electrification in less developed countries. Europe is a market leader of SHP technology. Optimal turbine designs are available and new technical developments offer automated operation of SHP. The present role of SHP in Europe in the development of renewable energy sources is discussed through this paper. The main producers of SHP electricity in Europe are Italy, France, Spain, Germany and Sweden. On the other hand, 10 European countries are ranked based on the total numbers of SHPs: Germany (7,512), Italy (2,427), France (1,935), Sweden (1,901), Spain (1,047), Poland (722), Romania (274), Portugal (155) and UK (120). The research shows that there is a considerable scope for development and optimization of this technology. This opens new perspectives because it has a huge, as yet untapped potential in most areas of Europe and can make a significant contribution to future energy needs. [ABSTRACT FROM AUTHOR]

Palm oil mill effluent (POME) is recognised as one of the biggest sources of pollution due to its eutrophying nature and methane emitting treatment. Although biogas recovery and utilisation are promoted through government initiatives, the motivation and support from mills still reported low in Malaysia. This paper aims to discuss the benefits and drawbacks of POME utilisation in the palm oil supply chain based on environmental, social and economic concerns to review the favourability of POME elimination. A zero effluent approach is introduced based on POME evaporation technique, undiluted clarification practice and water recycling strategy as an alternative for conventional POME management approaches. An integrated palm oil complex concept is proposed which includes new palm oil processing approach that eliminates POME and provides industrial symbiosis possibilities within palm oil upstream and downstream sectors to promote sustainability of palm oil industry with balanced economic and environmental advantages. A comparative study between POME utilisation (Case 1 and 2) and POME elimination (Case 3) in different perspectives is included in this work. In the economic view, the payback period of Case 3 is shorter (4 y) compared to Case 1 and 2 (4.3–8.3 y). In comparison, POME elimination technology is more environmentally friendly due to smaller water and land footprint, zero methane emission and minimum waste generation. Approximately 0.3% improvement in oil extraction rate can be potentially achieved by the proposed mill configuration in Case 3. One of the challenges in POME elimination implementation is the additional 0.25 kg steam requirement associated with evaporation of 1 kg water. The study provides insights on the feasibility of the proposed sustainable concept in Malaysia with consideration of government policies and programmes. The suggested POME elimination-based complex provides alternative option to mill owners who are uninterested to invest in biogas capturing facilities. • An integrated palm oil complex with POME elimination was proposed. • Comparative study between POME utilisation and POME elimination practices was conducted. • Economic evaluation of three (3) case studies was conducted. • POME elimination is the preferred alternative for sustainable POME management. [ABSTRACT FROM AUTHOR]

Conservation and restoration are crucial to maintaining a wide range of functions and services in wetlands, but it is difficult to find a reasonable and resource-efficient management option without sacrificing ecological values. In the present paper, we analyse the variability and dynamics of the chemical composition and energy potential of biomass from reedbeds, floodplain meadows, coastal meadows and reed canary grass cultivation in extracted peatlands. We observed that the chemical characteristics that are crucial for bioenergy production vary by biomass origin and over time. The bioenergy potential depends on biomass production and on the conversion method. The results indicate that the energy potential ranges from 122 to 190 GJ/ha per year in semi-natural floodplain meadows in the boreal zone. About 160 GJ/ha per year can be obtained from natural reedbeds but only about 120 GJ/ha per year from cultivated extracted peatlands. Using methane conversion, we can obtain only about 50%, and using ethanol conversion we can obtain less than 20% of the total energy potential of the herbaceous biomass of floodplain meadows. Although long-term studies on homo- and heterogeneous biomass production are required, we conclude that the local biomass of natural, semi-natural and artificial wetlands could contribute significantly to sustainable development. • Bioenergy production is higher in natural vegetation than in cultivated wetlands. • Carex spp. and Filipendula ulmaria are alternatives for wetland restoration. • Chemical composition and methane potential differ by biomass origin and over time. • Floodplain meadows have the highest energy potential among boreal zone wetlands. • Biofuel yield is higher through methane than through ethanol conversion. [ABSTRACT FROM AUTHOR]

Renewable energy sources can help combat climate change but knowing the land, water and carbon implications of different renewable energy production mixes becomes a key. This paper systematically applies land, water and carbon footprint accounting methods to calculate resource appropriation and CO 2 eq GHG emissions of two energy scenarios. The '100% scenario' is meant as a thinking exercise and assumes a complete transition towards bioenergy, mostly as bioelectricity and some first-generation biofuel. The 'SDS-bio scenario' is inspired by IEA's sustainable development scenario and assumes a 9.8% share of bioenergy in the final mix, with a high share of first-generation biofuel. Energy inputs into production are calculated by differentiating inputs into fuel versus electricity and exclude fossil fuels used for non-energy purposes. Results suggest that both scenarios can lead to emission savings, but at a high cost of land and water resources. A 100% shift to bioenergy is not possible from water and land perspectives. The SDS-bio scenario, when using the most efficient feedstocks (sugar beet and sugarcane), would still require 11–14% of the global arable land and a water flow equivalent to 18–25% of the current water footprint of humanity. In comparative terms, using sugar or starchy crops to produce bioenergy results in smaller footprints than using oil-bearing crops. Regardless of the choice of crop, converting the biomass to combined heat and power results in smaller land, water and carbon footprints per unit of energy than when converting to electricity alone or liquid biofuel. • The greenhouse gas emission savings of bioenergy entail large land and water use. • Land, water and carbon footprints of biofuels and bioelectricity are calculated. • A dynamic energy feedback loop is used to clarify gross and net footprints. [ABSTRACT FROM AUTHOR]

Worldwide, more than a billion rural dwellers live without electricity. Billions more endure awfully intermittent service even when connected to the grid. Most of these access challenged communities are in the Global South and may benefit from surging spread of distributed energy resources. However, associated investment necessity is large and so is the time required to address infrastructural bottlenecks. Recognising criticality of universal access to affordable, eco-friendly and reliable electricity in inclusive human development, the United Nations adopted 'affordable and clean energy' as one of the Sustainable Development Goals. To treasure electricity access, measurement of the same is important. The evolution of electricity access measurement has given rise to multi-tier, multi-parameter matrix. This improved measurement framework has facilitated researchers and policymakers in capturing various electricity access parameters in order to script focused energy strategy for the common man. This paper studies electricity availability, consumer aspiration and prevailing consumption in an impoverished, isolated, high-altitude valley, nestled in the Himalayas in India. It outlines evolving technology-aided, access measurement supported innovative access tier advancement opportunities in the valley. The result underscores the importance of consumer-focused approach for improving infrastructure utilisation. Consumer collaboration may result in fast, economical access advancement. Supply reliability may transform from abrupt complete disruption to gradual, cognisant decay. Such transition may encourage consumers to avoid costly, individual backup and instead use available resources sensibly. Embedding aspiration-supporting nudge in electricity regulation may promote co-operation, helping empowered consumers in scaling access tier affordably. • Electricity metering has advanced since comprehensive consumption reporting. • Metering advances can at present support inexpensive consumer Collaboration. • Collaborative consumption may help consumers scale access tier inexpensively. • Improved resource use may favourably impact affordability and consumer utility. • Participative consumption may promote equity, inclusivity and empowerment. [ABSTRACT FROM AUTHOR]

Net-zero emission and self-sustaining carbon-neutral have been widely encouraged and intensively explored in wastewater treatment, as the wastewater industry accounts for approximately 1.6% of global greenhouse gas (GHG) emissions. However, how to achieve net-zero GHG emission in wastewater treatment from a biological standpoint is still lacking. In this paper, the status of GHG (i.e. nitrous oxide (N 2 O), methane (CH 4) and carbon dioxide (CO 2)) production and emission in wastewater treatment was comprehensively reviewed. Generally, N 2 O emission contributes the majority of the total GHG emissions from wastewater treatment, and the dissolved N 2 O and CH 4 in the effluent should be paid more attention for the further GHG mitigation. Based on the newly identified microbial communities capable of nitrogen removal with less GHG emissions, several alternative integration systems for GHG mitigation were discussed. Coupling denitrifying anaerobic methane oxidation with anammox process shows high nitrogen removal performance and low GHG emissions, which is regarded as a more promising integration system for GHG mitigation. Moreover, the novel strategies to manage N 2 O and CH 4 as energy sources were also demonstrated, aiming to offset certain carbon footprint in wastewater treatment and thus attain net-zero GHG emission. In addition, future challenges and perspectives of above integration systems and strategies were discussed to facilitate the development of environmentally sustainable wastewater treatment. Finally, a prospective hybrid system integrating emission reduction and energy recovery was proposed as an example for achieving net-zero GHG emission from wastewater treatment. [Display omitted] • Status on GHG production and emission in each treatment unit is quantified. • Autotrophic microorganisms play important roles in mitigating GHG emission. • CH 4 is more feasible than N 2 O for energy recovery from mainstream wastewater. • Net-zero GHG emission integrates both emission reduction and energy recovery. [ABSTRACT FROM AUTHOR]

Polish economy is still undergoing the transformation process and seeks to converge with the most developed economies in Europe. While many economic reforms have been made, the generating sector was left to its own devices and lack of the investments caused that electricity supply in Poland is ineffective and not secure. The coal is a primary fuel and it constitutes over 80% of the energy mix. Thus, with energy mix restructuration ahead, the ambitious and balanced energy policy is highly required. The article aims to present the 2050 Energy Policy for Poland, which should facilitate the transformation of coal-based electricity generation system towards more sustainable and diversified energy mix. Comprehensive description and review of the current conditions of energy sector in Poland are accompanied with strengths and problems that need to be solved, taking into account European requirements. Additionally, in the paper the authors describe the development process of the Polish Energy Policy as they actively participated in the calculations of optimal energy mix for Poland. The manuscript presents the eMix model (energy mix optimization tool) developed by the authors, that constituted a background for Ministry of Economy to create Energy Policy. Hundreds of simulations scenarios were performed for the Ministry of Economy to provide the clear view of the electricity generation sector and to understand the impacts of all external stimuli to the mix. Assumptions for the model and results of calculations according to the policy scenarios are presented in the paper. Finally, the authors evaluate the final decisions of the policy makers, integrated in the Polish Energy Policy 2050, taking into account the challenges for the Polish power sector. [ABSTRACT FROM AUTHOR]

In order to keep sustainable development, the Chinese government has issued series of policies to reduce CO 2 emissions. Renewable energy technologies applied in building field, mainly including solar energy and geothermal energy technologies, are recommended because of advances of energy efficiency, environmental protection and economic sustainability. Carbon trading has been widely accepted as an effective market approach, but it hasn’t covered the renewable energy application in building projects in China as yet. Reasonable solutions should be proposed to encourage building projects to participate in the carbon trading market. This paper aims at establishing a feasible mechanism to help improve the carbon market for renewable energy application in buildings. To attend this goal, this paper introduces and analyzes the status of carbon trading market and the position for building projects in China. By comparing the present mechanisms, Programmatic CDM with building portfolio is considered appropriate for building projects with renewable energy application. Volume verifying method, the core of the mechanism, is modified to fit the building projects. Then five different specific cases are studied to prove the practicality and reasonableness of the methodology. Programmatic CDM with modified verifying method is concluded as the proper mechanism for renewable energy application in buildings in carbon trading market. [ABSTRACT FROM AUTHOR]

Sustainability has become a critical perspective in managing firms via a holistic approach by considering economic, environmental and social dimensions of firms. With the rising significance of sustainable development, the theories of sustainability in firms have evolved during the past six decades. This article offers a critical review of the evolving theories linking sustainability to firms, and discusses their implications for future renewable energy research. The relationships among different theories are critically analysed, and the directions for future research are discussed. The paper shows that, the main theories linking sustainability to firms, in a chronological order, are: 1) Corporate Social Responsibility, 2) Stakeholder Theory, 3) Corporate Sustainability, and 4) Green Economics. Currently various innovative approaches and new theories emerged, such as Co-evolution Theory and Multi-level Perspective, reflecting three directions of theory development, namely 1) shifting from "what" to "how", 2) growing use of interdisciplinary approach, and 3) towards broader systems. Renewable energy studies associated with firms and future research opportunities in this area are also critically analysed. The comprehensive review offered in this paper provides a useful reference for policy makers, corporate managers and researchers interested in corporate sustainability and renewable energy related studies. [ABSTRACT FROM AUTHOR]

This paper first reviews the potential causality from biomass energy to CO 2 emissions and economic development within relevant literature. Later, the paper examines statistically the impacts of biomass energy consumption on CO 2 emissions and GDP in the US. To this end, paper observes environmental and economic implications of biomass fuel usage throughout energy literature and launches asymmetric causality test to confirm/disconfirm the literature output. The findings of the tests indicate that biomass energy consumption per capita mitigates CO 2 emissions per capita and increases GDP per capita. Eventually, upon its output, this research asserts that biomass energy consumption can be an efficient policy tool for environmentally sustainable development in the US, and, that, hence, biomass production technologies and biomass consumption need to be promoted in other countries as well as in the US. On the other hand, analyses underline the fact that policy makers should consider as well some potential constraints of biomass energy usage such as land use constraints and carbon leakage from biomass production. Therefore, although this paper explores the remedial impact of biomass on environment and growth, one may suggest also that further possible works consider the effects of biomass sources in detail to minimize the some worsening influence of biomass usage on climate change. [ABSTRACT FROM AUTHOR]

The major contributor to global warming is human-generated greenhouse gases (GHGs) emissions that pollute the air. GHGs emissions are a global issue dominated by emission of carbon dioxide (CO 2 ). Notably, CO 2 accounts for an estimated 77% of GHGs and thus has a huge impact on the environment. The capture, sequestration, and utilization of CO 2 emissions from flue gas are now becoming familiar worldwide. These methods are a promising solution to promote sustainability for the benefit of future generations. Previously, many researchers have focused on capturing and storing CO 2 ; however, less effort has been spent on finding ways to utilize flue gas emissions. Moreover, several issues must be overcome in the field of carbon capture and sequestration (CCS) technology, especially regarding the cost, capacity of storage and the durability of the storage reservoir. In addition, this paper addresses new technology in carbon capture and sequestration. To make CCS technology more feasible, this paper suggests a sustainable method combining CCS and biofuel production using CO 2 as a feedstock. This method offers many advantages, such as CO 2 emission mitigation and energy security through the production of renewable energy. Due to the many advantages of biofuels, the conversion of CO 2 into biofuel is a best practice and may provide a solution to pollution while encouraging sustainability practises. [ABSTRACT FROM AUTHOR]

In this paper, five most emerging renewable energy sources are analyzed. These emerging renewables are either special or advanced forms of the mainstream energy sources (solar, wind, geothermal, biofuels, biomass, and hydro) or brand new technologies. The five emerging renewable technologies discussed in this paper include marine energy, concentrated solar photovoltaics (CSP), enhanced geothermal energy (EGE), cellulosic ethanol, and artificial photosynthesis. Marine energy is divided into wave energy, tidal energy, tidal/ocean currents, salinity gradient, and ocean thermal energy conversion. CSP technologies are divided into parabolic troughs, linear Fresnel reflectors, parabolic dishes, and solar towers. The process for developing EGE reservoirs is also explained in detail. Cellulosic ethanol energy extraction is explained for both cellulolysis and gasification. Artificial photosynthesis is explained by considering semiconductor particles, electrolyzers, artificial leaves, and dye-synthesized solar cells. Each emerging renewable source's explanation is followed by its market share, challenges, implications for increased adoption, future prospects, and drawbacks. [ABSTRACT FROM AUTHOR]

Simulation is a well-established and effective approach to the development of fuel-efficient and low-emissions vehicles in both on-highway and off-highway applications. The simulation of on-highway automotive vehicles is widely reported in literature, whereas research relating to non-automotive and off-highway vehicles is relatively sparse. This review paper focuses on the challenges of simulating such vehicles and discusses the differences in the approach to drive cycle testing and experimental validation of vehicle simulations. In particular, an inner-city diesel-electric hybrid bus and an ICE (Internal Combustion Engine) powered forklift truck will be used as case studies. Computer prediction of fuel consumption and emissions of automotive vehicles on standardised drive cycles is well-established and commercial software packages such as AVL CRUISE have been specifically developed for this purpose. The vehicles considered in this review paper present new challenges from both the simulation and drive-cycle testing perspectives. For example, in the case of the forklift truck, the drive cycles involve reversing elements, variable mass, lifting operations, and do not specify a precise velocity-time profile. In particular, the difficulties associated with the prediction of productivity, i.e. the maximum rate of completing a series of defined operations, are discussed. In the case of the hybrid bus, the standardised drive cycles are unrepresentative of real-life use and alternative approaches are required in the development of efficient and low-emission vehicles. Two simulation approaches are reviewed: the adaptation of a standard automotive vehicle simulation package, and the development of bespoke models using packages such as MATLAB/Simulink. [ABSTRACT FROM AUTHOR]

Turkey’s rapid economic growth followed by increasing gap between domestic energy production and consumption signifies the large-scale integration of low-carbon and renewable resources into energy system. Turkey’s energy demand is increasing and supplying fossil energies such as oil and gas is becoming more challenging due to the lack of domestic hydrocarbon resources. The country is facing two main issues; first, maintaining energy balance and second, handling environmental issues. Nevertheless, Turkey has substantial renewable and low-carbon energy resources with co-benefits for the country’s fast growing economy and environmental sustainability. This paper aims to present a comprehensive update on Turkey’s renewable and low-carbon energy sector. It reviews not only the current status of the technology, policy and economy, but also provides an insight into the social aspects as well. From a policy point of view, the paper critically discusses Turkey’s energy strategy and perspectives and from the social point of view, the paper argues that there is a research gap in recent literature regarding public awareness and social acceptance of low-carbon energy technologies. Also, the future challenges for promoting low-carbon society in Turkey are discussed in terms of sustainable development and socio-environmental conditions. [ABSTRACT FROM AUTHOR]

Recognizing the multidimensional role that hydropower can potentially play in achieving a more sustainable energy supply system, this paper reviews a series of published economic, environmental and social indicators that are often used to characterize this energy source. Getting the right balance between measures assessing benefits and costs is often a challenge in complex evaluations. The current paper argues that present studies sometimes set system boundaries too narrowly so that they omit key factors associated with hydropower. In particular, the role that hydroelectric resources can play to stabilize the overall electrical grid, and thus to leverage investments in other intermittent renewables, is only rarely accounted for in sustainability assessments. Based on a broad literature review, the authors articulate two key recommendations for future assessments: first, that such assessments should reflect on policy issues as well as environmental challenges with respect to existing hydropower potential within the current framework; second, that system boundaries should be extended not only to allow broad hydrological, ecological and geological assessments, but also to reasonably estimate hydro's potential benefits to the functioning of the overall electrical grid. [ABSTRACT FROM AUTHOR]

It is a popular fact that the world's dependency on fossil fuel has caused unfavourable effects, including lessening crude oil reserve, decreasing air quality, rising global temperature, unpredictable weather change, and so on. As the effort to promote sustainability and independency from fossil fuel, bioethanol is now favoured as the blend or fossil petrol substitute. However, the feedstock functionality of first generation bioethanol production is restricted due to its edibleness since it would clash the feeding purpose. Second generation bioethanol production fulfils the impractical gap of first generation since it employs non-edible feedstock sourced from agriculture and forestry wastes. Lignocellulosic and starchy materials in them are convertible to fermentable sugars that are able to be further processed, resulting anhydrous bioethanol as the end product. This paper critically reviews the existing variance of second generation bioethanol production methodologies, namely pre-treatment, hydrolysis, fermentation and distillation, as well as the worth of second generation production for future reference. The discussions in this paper are also fit as the fundamental for feasible planning of second generation bioethanol production plant. [ABSTRACT FROM AUTHOR]

Solar home systems (SHSs) are the real hope for electrification of the off-grid areas in Bangladesh by utilizing the solar energy in renewable and sustainable basis. This paper demonstrates the solar energy prospect, the present status and dissemination schemes of SHSs in off-grid and coastal areas of Bangladesh by several government and Non-government organizations (NGOs). The country has an average daily solar radiation ranges between 4–6.5 kWh/m 2 . Currently, more than 3.8 million SHSs of capacity range 10–135 Wp (watt peak) with a total capacity of 150 MW have been disseminated in rural and isolated areas in Bangladesh. In this paper, ten case studies of capacity 20 Wp, 30 Wp and 42 Wp were investigated to evaluate economic viability at two randomly selected villages in Sirajgonj district and Jessore district, Bangladesh. The analysis showed that the SHSs for small business enterprise and household with small income generation are economically viable rather than only household lighting. [ABSTRACT FROM AUTHOR]

Biobased products are complete or partial derivatives from naturally occurring/growing materials such as agricultural, plants, and forest materials and serve as an alternative to traditional product derivatives of petroleum. Technically, biobased product counterparts can replace almost every fossil resource-based industrial material. Adopting life cycle analysis and circular economy concepts has also accelerated the move towards biobased products. It meets the criteria for easy recycling and can facilitate the shift from linear fossil-based productions to a greener circular economy. In line with the Renewable and Sustainable Energy Reviews (RSER) policy, this Virtual Special Issue (VSI) published two types of articles, high-quality review papers and original research papers with a strong review component. After a rigorous peer-review process, 32 articles were accepted and published in this VSI. This editorial overview these articles and examines their contribution to the field. This RSER VSI has contributed with new insights on value-added biobased products from various bioresources to their applications, technical challenges and advancement in a sustainable manner. • VSI is focused on the recent development of biobased biorefineries. • Greener technologies offering biobased products. • Sustainable bioprocesses and bioproducts development from bioresources. [ABSTRACT FROM AUTHOR]

Even with a long lifetime of 25–30 years of green energy production, end-of-life treatment of solar photovoltaic modules can negatively impact the environment if not handled properly. This is particularly urgent when the use of photovoltaics has grown at an unprecedented rate, generating clean energy all over the world. Therefore, it is essential to develop commercially viable end-of-life recycling technologies to guarantee a sustainable future for the photovoltaic technology. Silicon photovoltaic modules, the most popular photovoltaic technology, have been shown to be economically unattractive for recycling - the materials are mixed and difficult to separate, and have low value, so that the cost of recycling is hardly recovered. In this paper, we review the state-of-art recycling technology and associate it with a quantitative economic assessment to breakdown the cost structure and better understand the presented economic barrier. The techno-economic review allows us to identify essential framework and technology changes required to overcome the current barrier to implementing commercial-scale recycling. (i) The authority may impose price signal to impress direct landfill of end-of-life modules while proactively establish an effective collection network. (ii) The local recyclers may aim at value recovery as a step beyond mass recovery, especially targeting at recovery of intact silicon wafers and silver to guarantee the recycling revenue. Meanwhile, efforts should be put on reducing the recycling processing cost. (iii) Photovoltaic module manufacturers may take end-of-life responsibilities and up-design the product to facilitate end-of-life recycling, which includes features for simple disassembly, recycling, and reducing or eliminating the use of toxic components. • Sustainable photovoltaic technology requires proper end-of-life management. • The techno-economic analysis reveals new insights to overcome the economic barrier. • Photovoltaic module recycling is a collaborative action among all stakeholders. • Upcycling can achieve maximum environmental and economic benefits. • Further technologies should aim at value recovery and up-front eco-design. [ABSTRACT FROM AUTHOR]

Abstract In the current energy transition, there is a growing global market for innovative ways to generate clean energy. Storage technologies are potential and flexible solutions to deal with the intermittent nature of renewable resources. Closed mines can be used for the implementation of plants of energy generation with low environmental impact. This paper explores the use of abandoned mines for Underground Pumped Hydroelectric Energy Storage (UPHES), Compressed Air Energy Storage (CAES) plants and geothermal applications. A case study is presented in which the three uses are combined in just one mine. This preliminary study allows estimating an electrical energy generation of 153 and 197 GWH year−1 at the UPHES and CAES systems, respectively, and a thermal energy generation of 0.41 GWh year−1 at the geothermal system, with a total cost of 358 M€. An underground closed mine can be used to store energy for re-use and also for geothermal energy generation, providing competitive renewable energy with a low CO 2 footprint. These initiatives aid to ensure sustainable economic development of communities after mine closure. Highlights • Energy storage systems are required to increase the share of renewable energy. • Closed mines can be used for underground energy storage and geothermal generation. • Underground closed mines can be used as lower water reservoir for UPHES. • CAES systems store energy in the form of compressed air in an underground reservoir. • The geothermal use of water from a mine allows heating and cooling nearby buildings. [ABSTRACT FROM AUTHOR]

Abstract The cultivation of marginal lands for bioenergy production has recently become a topic of research interest for the agronomic and agricultural economy scientific communities. The growing availability of arable land in the Mediterranean regions, as a consequence of the decline of cereal cropping systems and grain legume, provides ample opportunities for performing successful feedstock production on unmanaged areas. This paper seeks to capture and analyze ongoing and emerging questions concerning bioenergy production on marginal lands in the Mediterranean area in a framework of sustainability indicators. A qualitative methodology was adopted to evaluate the effectiveness of eight critical issues that bio-energy developers, scholars and policymakers should consider in terms of agronomic, techno-economic and methodological practices for growing bioenergy feedstock. The issues investigated on selected case studies are: Greenhouse gas emissions; soil quality; land restoration and phytoremediation capacity; water use and efficiency; biodiversity; land use/cover changes; farmers' willingness and acceptance of new agro-system, and profitability of value chain. Starting from an in-depth analysis of the definition of marginal land from the perspective of ecosystem service cascade, we synthesize how these challenges are nowadays addressed and which are the key bottlenecks, trends and potential directions for guiding future research into bioenergy production in the Mediterranean regions. The findings of this study suggest that dedicated energy crops can be grown on marginal lands with substantial positive effects in terms of sustainability aspects, although more efforts should be carried out through agronomic research especially on water use efficiency and biodiversity conservation, as well as by national and EU institutions and policies for promoting economic opportunities and integration with surrounding agro-ecosystems and farmers' involvement. Developing a site-specific landscape design with the use of Life Cycle Assessment and certification schemes with sustainability indicators is of primary importance for the effective bioenergy production on marginal lands. Graphical abstract fx1 Highlights • Key issues concerning bioenergy production in the Mediterranean area were analyzed. • The concept of marginal land was analyzed. • The use of tailored GBEP sustainability indicators was fostered. • Eight critical issues were reviewed discussing key results and future challenges. • Possible technical and policies improvement solutions are proposed. [ABSTRACT FROM AUTHOR]

Access to clean and affordable modern energy services has been widely recognised as a significant factor for enabling social and economic development. Stand-alone systems and mini-grids are presumed to play an important role in the provision of sustainable energy to those people who currently lack access. Accordingly, an increasing number of small-scale energy projects are being implemented in developing countries and emerging economies. However, despite the large number of energy development projects, only limited evidence exists about the actual contribution they make to sustainable development. This paper addresses this research gap by providing a systematic assessment of three selected impact pathways based on the evaluation of over 30 small-scale sustainable energy projects. Applying a theory-based evaluation approach in the form of a contribution analysis, the aim of this research is to better understand if and how these types of technical interventions can create development outcomes and impacts. The results show that technological issues are often not the most decisive factor in achieving development effects, but that embedding the technology in a set of actions that address social, cultural, economic and environmental aspects is essential. [ABSTRACT FROM AUTHOR]

The Sun is the primary energy source for all life on Earth. Solar energy is clean and is available all over the world. The total energy produced, in 2016, was 7236 MWh, while the total consumed was 6660 MWh. The average photovoltaic energy generated was 255 MWh, which accounts for 3.5% of the total production and 8.2% of the RES (3096 MWh). Investments in renewable energy in Romania began in late 2008, when Green Certificates were granted by Law no. 220. In this paper, we review the photovoltaic system development in Romania, from 2011, when the market began to develop, to the present day. The climate change and air pollution have to be slowed down and reduced by implementing renewable and sustainable solutions in order to generate electricity. The photovoltaic industry has an important role in Romania's development, both economically and environmentally and by having the “unlimited resource” advantage, it is a good alternative to fossil fuels. Now, the largest solar park in Romania, with 332,000 operational PV units, located in Ucea de Sus, Brasov County and commissioned in 2013, has an installed capacity of 82 MW, and covers a land surface of 200 ha. 178 years ago, French physicist Edmond Becquerel discovered the photoelectric effect, in 1839. At the moment, the typical power of solar PV modules is less than 500 W, depending on efficiency and temperature sensitivity. Currently, long-term research on photovoltaic cells focus on increasing the power output, increasing the efficiency and reducing the temperature sensitivity. [ABSTRACT FROM AUTHOR]

Global firms are increasingly adopting greenhouse gas mitigation targets in response to climate change. These targets serve as a spur for carbon mitigation initiatives, provide guidelines to select appropriate mitigation actions, and set the standards to measure the progress of the mitigation efforts. Despite their important functionalities, firm-level mitigation targets have rarely been studied. In this paper we aim to provide a comparative view on mitigation targets set by global firms across different countries and industrial sectors. The analysis focuses on four dimensions, i.e., adoption, metric, scope, and stringency. We find Japan far leads the other major countries in terms of target adoption, but the targets of Japanese firms are generally less stringent. Canadian firms are laggards in both target adoption and target stringency. The mitigation targets are also considerably uncommon among Australian firms. Firms in developing countries fall behind in target stringency and display a significantly greater divergence than developed countries in sectoral adoption rate. The European Union firms are most likely to cover the emissions in their supply chains in targets. Target stringency has substantially tightened from 2005 to 2012. For all the countries in this study, around 95% of the firm-level targets are more stringent than the Intended Nationally Determined Contributions submitted to the Paris Agreement. Setting mitigation target has a significant positive impact on both the likelihood of investing in renewable energy and the amount of investment in renewable energy. However, there is no evidence that more stringent targets lead to higher investment. These findings point to the most pressing issues with regard to corporate mitigation target-setting that policymakers and corporate management should address. [ABSTRACT FROM AUTHOR]

The research presented in this paper has two main objectives. First, it aims to generate an assessment tool for ranking and selecting the most sustainable domestic water-heating system (WHS) (with the lowest economic, environmental and social impact) that could be applied in any location and with any demand. Second, it aims to ascertain which WHS is the most sustainable in places with a climate and solar radiation like that of Barcelona, Spain, where a minimum solar contribution to domestic water heating is compulsory for new buildings and significant renovations. Multi-criteria decision analysis was employed to create the optimised flexible assessment tool. The Delphi method was followed to perform the surveys, and to provide the objectivity required in the identification of impacts, the definition of indicators and the assignment of weights. The most relevant criteria were determined: annual cost, material consumption, energy consumption, GHG emissions, space requirement, visual impact and occupational risks. The resulting tool was tested by analysing twelve domestic WHS, including two conventional systems, and ten combinations of five solar thermal technologies with two conventional systems as backup for a changing room in a sport centre located in Barcelona. The two conventional WHS studied were a natural gas-fired condensing boiler and an electric water heater. The five solar thermal technologies were: a flat plate with a harp design, a flat plate with a serpentine design, a heat-pipe evacuated tube, a direct-flow evacuated tube, and a direct-flow evacuated tube with CPC. The dynamic thermal simulation programme T*SOL was used to dimension the solar thermal systems. Two sensitivity analyses were carried out: one on weights and one on references. The tool proved very useful in the assessment of these systems, and could also help in decision-making processes to select the most sustainable WHS for other locations and domestic hot water demands. [ABSTRACT FROM AUTHOR]

Environmental, economic and political pressures have driven the interest towards the search of sustainable feedstock for biofuel production. At present, macroalgae (green, brown and red marine seaweed) is getting growing consideration as an alternative resource for sustainable biomass to produce biofuels, biochemical and food. The unique chemical composition and wide variation in the availability create various opportunities and also challenges for bio-based energy production. Recently, numerous studies have taken place in the exploitation of seaweed as carbon sources for the bioethanol production. Thus, this paper attempts to highlight the characteristics, processing techniques and potential applications of the seaweed. The present review also focuses on recent innovative approaches for the sustainable production of bioenergy from seaweed. [ABSTRACT FROM AUTHOR]

Despite the historical priority to grid-based electrification in South Asia, two out of every five people in the region still live without access to electricity. Due to various limitations of conventional grid-based rural electrification, as brought out by a number of studies and reports, demand for alternative models such as renewable energy based off-grid and distributed generation solutions are gaining increasing attention globally. However, due to the absence of any study that could juxtapose these two modes in terms of their merits and demerits, it is difficult to infer on their relative superiority or inferiority. In view of that, this paper makes an attempt to connect the dots by carrying out an extensive review of the literature, to analyse the role of grid and off-grid options in facilitating rural electrification, and come out with a comparative assessment of their costs and impacts on the South Asian countries. The paper infers that instead of considering each of the modes of electrification in a standalone manner and perceiving them as mutually exclusive or competing with one another, as usually perceived in the policy sphere, off-grid electrification can actually be considered as a complementary mode and should ideally be integrated with grid expansion to serve the bigger cause of ensuring universal and sustainable rural electrification in South Asia. [ABSTRACT FROM AUTHOR]

Global warming has posed a great challenge to the survival of mankind. The increasing atmospheric concentration of carbon dioxide is widely recognized as the largest contributor of global warming. Hence, world-wide attention towards energy conservation has grown markedly to reduce the carbon dioxide emission. In the context of building energy performance, the ancient wisdom of using the earth as temperature moderator against harsh weather has impressive potential to become a solid solution against the energy inefficiency of Heating, Ventilation, and Air Conditioning system (HVAC) in building. This creative and traditional passive cooling technique has been also made it possible to achieve most criteria of sustainable development concerning the world׳s growing housing demand, climate change, fossil-fuel depletion as well as limited land area and resources. In this paper, underground buildings were reviewed from preliminary aspects such as historical background, classification and subsequent thermal energy performance criteria. It has tried to elaborate the thermal performance variables, and conduct further study of benefits and drawbacks of this passive cooling technique toward different perspectives of sustainable development. With intention to gain wide acceptance in the modern society, this paper has proposed a conceptual design of earth sheltered home, which incorporated different types of the building techniques. Eventually earth sheltered buildings worldwide were summarized in a well illustrative form to highlight the different designs, applications, locations, timelines and climates. In addition, a deductive model is graphically represented for the virtual overview of underground structures that set the foundation to further investigate sustainability of this building envelope technique. [ABSTRACT FROM AUTHOR]

The expectation of sustainable development of energy and environment has widely attracted public׳s attention, and the high-efficiency heat transfer device is greatly needed. As a new heat transfer device, pulsating heat pipe (PHP) has been considered have a bright prospect due to its obvious advantages – simple structure, low cost and excellent heat transfer capability. A number of experimental and theoretical researches have been conducted on PHP in the past decades since it was proposed by Akachi in 1990. However, due to the hydrodynamic and thermodynamic coupling effect, the operational mechanism of PHP is extremely complex and has not been completely revealed so far. With great expectation of applications for the PHP in the near future, this paper attempts to review the development of PHP on the basis of systematic summary of the latest results of both experimental and theoretical studies. Meanwhile, some promising and innovatory applications of the PHP are also reported. This paper is expected to provide basic reference for future researches. [ABSTRACT FROM AUTHOR]

This paper aims to identify institutional improvement measures to promote environmentally sustainable ocean renewable energy development by analyzing how the environmental assessment systems in South Korea are integrated into this development. The measures identified in the paper include (1) consideration of subjecting ocean renewable energy development to strategic environment assessment in order to assess the adequacy of relevant project plans and the validity of site selection at early stages, (2) new standards, such as the area of occupancy, integrated within the environmental impact assessment at the project implementation stage, (3) integration of the environmental impact assessment with the procedures for Consultation on Utilization of Sea Areas to reduce development cost and delays and (4) reinforcement of post-development environmental monitoring processes to eliminate uncertainty or lack of knowledge about potential impacts on marine environment and habitat caused by development. [ABSTRACT FROM AUTHOR]