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• Numerical modeling of thermoacoustic devices can be classified into 1-D linear and 2-D/3-D non-linear models. • Linear thermoacoustic models lose their utility, in the high amplitude and high frequency regime. • CFD modeling has proven to be an effective tool in capturing the nonlinearities associated with standing wave thermoacoustic devices. • Flow dominance in a 2-D plane inside SWTADs has allowed the performance evaluation of these devices utilizing 2-D CFD models. • CFD modeling of standing wave thermoacoustic devices primarily focus on stack and the region around it. Global environmental concerns have brought the challenge of developing renewable energy technologies to cope up with the world energy needs. Thermoacoustic devices present themselves as a viable alternative to replace conventional refrigeration and power systems due to their minimal carbon footprint. These devices involve complex flow physics encompassing transient phenomenon and conversion of acoustic and thermal energies for their efficient performance. With the rapid advancement in computational capabilities, extensive numerical work is carried out to gain detailed understanding of the thermoacoustic devices. In this paper, a detailed review of the numerical modeling techniques that have been applied in the field of Standing Wave Thermoacoustic Devices (SWTAD) is carried out. At first, a brief review of analytical method is presented and the need for numerical modeling is highlighted. Numerical modeling techniques ranging from simplified linear to detailed Computational Fluid Dynamics (CFD) models are reviewed in detail. Model configurations, capabilities and tools developed and utilized so far in the research area are summarized. Challenges associated with SWTAD and applications modeled using CFD are discussed. The paper concludes with some useful recommendations regarding the numerical modeling of thermoacoustic devices. [ABSTRACT FROM AUTHOR]

As a result of the COVID-19 epidemic, a worldwide economic slump has reduced the depletion of natural resources, lowering their costs. The loss of renewable energy profitability might hinder the attainment of specified goals of sustainable development goals. By using Chinese provinces data from 1995 to 2020, this research examined the relationships between renewable energy investment (REI), green finance (GFI), growth of the economy (GDP), renewable energy production (REP), and private sector participation (PSP) in China. According to this analysis, REI, REP, and GFI are more variable throughout the given period than GDP. And PSP. A bidirectional substantial causal correlation between REI and REP was identified using the Generalized method of moments (GMM). Still, the regression coefficient between GDP and REI and REI. and GFI has a one-way causal relationship. There was no evidence that the PSP directly impacted the REI. Based on the empirical findings of this research, we propose that policies be designed to reduce volatility in REI GFI, and REP and increase support to improve sustainable economic development and environmental and renewable energy production. Examine between green financing and environmental conservation for long-term environmental quality. • There is a dire need to measure the examined the relationships between renewable energy investment (REI), green finance (GFi). • Bidirectional substantial causal correlation between REI and REP was identified using the Generalized method of moments (GMM). • There was no evidence that the PSP had a direct impact on the REI. • This paper improve sustainable economic development as well as environmental and renewable energy production. [ABSTRACT FROM AUTHOR]

The application of green energy technologies to supply berthed ships in ports with the necessary power instead of using their diesel generators is considered an initiative towards sustainability and climate change mitigation. Therefore, the current paper investigates the implementation of solar panels, offshore wind turbines, and hydrogen fuel cell systems as green technologies to supply the berthed ships with power in three Egyptian ports. The power requirements are determined by analyzing the annual ship traffic data and estimating the energy demand for each ship type. As a relevant result, the annual energy demand for ships berthed in Alexandria, Damietta, and Safaga ports is about 44.2 × 103 MWh, 22 × 103 MWh, and 5.6 × 103 MWh, respectively. The analysis results reveal a potential annual carbon dioxide reduction of 31.7 k-tons, 15.7 k-tons, and 4.2 k-tons in Alexandria, Damietta, and Safaga ports, respectively. From an economic perspective, the levelized cost of energy (LCOE) of solar panels is estimated to be 80.7–90.1 $/MWh, while hydrogen fuel cells have a cost of 166.8–172 $/MWh. On the other hand, LCOE in the case of wind turbines is estimated to be 140.8 $/MWh for Alexandria ports, 178.3 $/MWh for Damietta port, and 103.9 $/MWh for Safaga port. [ABSTRACT FROM AUTHOR]

Corporate environmental information disclosure systems are important for controlling pollution caused by corporate activities. However, different motives associated with environmental information disclosure have different influences on the financing of companies. This paper adopts renewable energy companies instead of high pollution industries as a research object. The study analyzes the resource-dependent disclosure motivation of renewable energy companies, and the impact of environmental information disclosure on the scale and cost of direct and indirect financing. The results show the following. First, renewable energy companies in China have a resource-dependent motivation to disclose environmental information, with a gap between the level of environmental information disclosure and their actual environmental performance. Second, renewable energy companies may obtain more direct financing amount and lower indirect financing costs, but cannot obtain lower direct financing costs and more indirect financing amount by improving the level of environmental information disclosure with the resource-dependent motivation. Third, there are differences in the specific incentives for environmental information disclosure among the Eastern, Middle, and Western regions of China. The government needs to standardize the detailed rules and standards of the corporate environmental information disclosure system, and improve the environmental protection awareness and the implementation of green credit in the Western region. [ABSTRACT FROM AUTHOR]

Integrating electric vehicles (EVs) into the electric power system poses significant challenges to grid operation and planning due to the potential constraints on the power system. To minimize grid congestion, the best option is to increase the production of photovoltaic (PV) energy for domestic use and EV charging stations. This paper addresses the nexus of technical, financial, and environmental effects of customer involvement in economic development and load management. In this paper, a new model design of solar-powered EV charging stations is proposed and implemented in HOMER Grid, and a case study has explored how economic, technical, and energy management benefits can be achieved through customer energy involvement and the integration of PV-based charging stations. The proposed PV-based charging stations contribute toward the energy management of the region, and the study observes the real-time optimal charging and discharging strategy of PV-based grid-connected charging stations. The case study results show that the investigated area can produce 1,070,804.096 MWh/year of energy through maximum customer involvement, consequently reducing overall energy costs. Moreover, the study demonstrates that the selected region can produce 86,961,688 kWh/year through the PV system, achieving 363,899 charging sessions per year, offering maximum advantages and facilitation for EV charging. The proposed model applicability shows that large-scale customer involvement can bring significant techno-economic benefits and attract regional investments. • This paper proposes a new design of a grid-tied renewable energy system. • It investigates the energy economics and environmental effects for a practical location. • The research examines energy management including PV systems and electric vehicles. • The results of proposed model are compared with other models. [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]

For realizing environment protection and carbon emission reduction strategy, the dominant position of renewable energy in the future power system has been clarified. Planning economic and efficient flexible resource system is the basis to balance multi fluctuations caused by large amount of renewable energy integration and ensure the safe operation of the whole power system. Considering that the flexibility adjustment demands of different links of the power system are not independent, but influence and restrict each other, this paper focuses on how to collaboratively allocate multi-flexible resources and achieve corresponding balancing interaction strategy. Firstly, a flexible resource system is composed through a fuzzy TODIM improved PROMETHEE-II model. Secondly, a multi-flexible resource collaborative allocation optimization model is proposed, which considers the Stackelberg game relationship of flexibility adjustment demand and ability in different links of the power system under varied fluctuation scenarios. The scientificity and effectiveness of the proposed model are verified by a practical case, and key incentive factors and specific development suggestions for improving flexible resources application efficiency are identified simultaneously. Since the collaborative planning of flexible resource system have not been deeply discussed by scholars yet, thus, this research contributes to the literature and expand the knowledge. • Design an effective flexible resources system through TODIM improved PROMETHEE-II model under multiple application scenarios. • Construct flexible resources optimal allocation scenarios according to the power generation and consumption characteristics of the new power system. • Construct a two-layer flexible resources equilibrium allocation model based on Stackelberg game theory. • Propose a multi-stage flexible resources equilibrium allocation model solution method. • Identify key factors influencing the allocation strategy of flexible resources in the new power system. [ABSTRACT FROM AUTHOR]

With the increasing demand for electricity, more and more fossil fuels are used to generate electricity which leads to energy shortage and environmental pollution. Therefore, using Renewable Energy Sources (RESs) and developing sustainable smart grid have become a common global priority: Since RESs, like solar and wind energy, are inherently unstable, hydrogen energy, as a completely clean new energy, has received widespread attention: I-Energy, which combines information and energy, is a new research direction in smart grid. Furthermore, the household electricity usage accounts for 41% of the total power consumption. Therefore, Household Intelligent Electricity System (HIES), combining hydrogen energy and i-Energy, becomes smart solutions. In this paper, we review the scientific literature for hydrogen energy and i-Energy on HIES, including recognition of electricity appliances, establishment of power consumption model, human activity analysis, smart interactive terminal, home energy management system, distributed power supply and district coordinated power utilization. Finally, we summarize the challenges and give the solutions concerning HIES, and this work can give a useful reference to new energy used model and environment protection. • A new application of Hydrogen Energy on Household Intelligent Electricity System (HIES). • A comprehensive overview of Hydrogen Energy and I-energy on HIES. • Combining internet with traditional electricity to analyses I-energy on HIES. • Summarizing the challenges and corresponding solutions concerning HIES. [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]

This paper provides an overview of the various processes used in the recovery of platinum group metals (PGMs) from spent catalysts. PGM recovery is interesting due to their vast industrial applications and high market prices. From the use of renewable resources and environmental protection viewpoints, recycling of PGMs receives wide concerns as the amounts of spent catalyst increases dramatically. PGM recovery from spent catalysts is a challenge due to the fact that spent catalysts are diverse and complex in terms of material and component makeup as well as the original catalyst's manufacturing processes. The state of the art recovery of PGMs from spent catalysts by pyrometallurgy and hydrometallurgy techniques is highlighted and existing advantages and disadvantages of these techniques are analyzed in this paper. This review also pointed out that the promising processes of PGM recovery are economical, environmentally friendly and large-scale means. [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]

Passive design strategies are important for achieving building sustainability given their proved influences over the building performance in both energy and indoor environmental aspects. The building layout, envelope thermophysics, building geometry and infiltration & air-tightness are major passive architectural parameters to improve the building energy efficiency. In this paper, a comprehensive literature review on simulation-based approaches to optimize passively designed buildings is conducted and corresponding research gaps are identified. Based on existing research methods, modelling experiments on a generic building are conducted to integrate robust variance-based sensitivity analyses with an early-stage design optimization process. Proposed mixed-mode ventilation and lighting dimming control algorithms are applied to the EnergyPlus model to simulate the total lighting and cooling energy demands by incorporating the related design criteria in a local green building assessment scheme. The non-dominated sorting genetic algorithm (NSGA-II) is then coupled with the modelling experiment to obtain the Pareto frontier as well as the final optimum solution. Different settings of NSGA-II are also investigated to improve the computational efficiency without jeopardizing the optimization productivity. Furthermore, the sensitivity of optimum design solutions to external environmental parameters in hot and humid areas are explored. Findings from this study will guide decision-makers through a holistic optimization process to fulfill energy-saving targets in a passively designed green building. [ABSTRACT FROM AUTHOR]

The term smart grid (SG) has been widely used in both the United States (U.S.) and Canada to represent multiple visions and configurations of electricity system change. In both countries policies, programs, and initiatives have emerged to promote technological and social changes associated with SG, and different patterns of SG implementation and governance are apparent at local, regional, and national levels. This paper reports on a comparative analysis of SG media content in nationally-circulating newspapers in the U.S. and Canada to explore patterns of SG conversations in the two countries. Media reporting about SG provides a valuable lens that reflects public discourse and also contributes to setting the public agenda by shaping public opinion and framing key issues. Despite similarities in terms of policy, program design, and SG deployment strategies, several prominent differences between the two countries emerge in public conversations. Firstly, Canadian SG newspaper content focuses more on implementation and describing people's experiences with smart meters, while the U.S. content focuses more on commercial opportunities with more reference to private sector actors and various technological components beyond smart meters. Secondly, although media coverage in both countries frequently highlights technological and economic benefits of SG, positive SG framing is more frequent in the U.S. newspapers than in the Canadian ones. Negative SG portrayals, including cultural, political and health and safety risks, are more frequently mentioned in the Canadian newspapers. These differing SG framings could be due to national level cultural differences. In the U.S, considered to be more of an individualistic society, there is more emphasis on business opportunities, being entrepreneurial, and more private sector involvement in the electricity sector. By contrast, in Canada, public authorities, more prominent in the electricity market than in the U.S., play a key role in smart grid deployment. Furthermore, in Canada, considered to have more social support structures for individuals and communities, there was more emphasis on the experiences of people. This suggests that cultural differences at the national level be a further contextual lens helpful to policy makers and technology proponents as they embark upon energy system change initiatives. [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]

In order to understand the climate effects of a bioenergy system, a comparison between the bioenergy system and a reference system is required. The reference system describes the situation that occurs in the absence of the bioenergy system with respect to the use of land, energy, and materials. The importance of reference systems is discussed in the literature but guidance on choosing suitable reference systems for assessing climate effects of bioenergy is limited. The reference system should align with the purpose of the study. Transparency of reference system assumptions is essential for proper interpretation of bioenergy assessments. This paper presents guidance for selecting suitable reference systems. Particular attention is given to choosing the land reference. If the goal is to study the climate effects of bioenergy as a part of total anthropogenic activity the reference system should illustrate what is expected in the absence of human activities. In such a case the suitable land reference is natural regeneration, and energy or material reference systems are not relevant. If the goal is to assess the effect of a change in bioenergy use, the reference system should incorporate human activities. In this case suitable reference systems describe the most likely alternative uses of the land, energy and materials in the absence of the change in bioenergy use. The definition of the reference system is furthermore subject to the temporal scope of the study. In practice, selecting and characterizing reference systems will involve various choices and uncertainties which should be considered carefully. It can be instructive to consider how alternative reference systems influence the results and conclusions drawn from bioenergy assessments. [ABSTRACT FROM AUTHOR]

High levels of observed city involvement in energy and climate initiatives indicate that free-riding has been much less of a barrier to local climate protection efforts than suggested by theories of collective action. This study investigates why local governments have adopted various energy and climate change policy instruments despite the non-excludability of climate benefits. This paper advances theories of institutional collective action (ICA) and policy diffusion by testing ICA based hypotheses that local officials are able to overcome collective action problems to the extent that the costs of these initiatives are minimized through policy network interactions, the extent to which climate action produces localized benefits or compliments local environmental, development or growth management efforts, and the extent to which energy and climate protection efforts generate selective benefits to elected and appointed local government officials who advance their career interests depending on the existing configurations of political system institutions. Analysis of adoptions of the Climate Protection Agreements by Florida Cities indicates larger cities are more likely to adopt climate agreement, while district elections decrease the likelihood of climate policy adoption. Moreover, economic development rather than growth management or environmental problem situation is linked to climate initiatives. [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]

Wind power is a type of clean and renewable energy, and reasonable utilization of wind power is beneficial to environmental protection and economic development. Therefore, a short-term hydro-thermal-wind economic emission dispatching (SHTW-EED) problem is presented in this paper. The proposed problem aims to distribute the load among hydro, thermal and wind power units to simultaneously minimize economic cost and pollutant emission. To solve the SHTW-EED problem with complex constraints, a modified gravitational search algorithm based on the non-dominated sorting genetic algorithm-III (MGSA-NSGA-III) is proposed. In the proposed MGSA-NSGA-III, a non-dominated sorting approach, reference-point based selection mechanism and chaotic mutation strategy are applied to improve the evolutionary process of the original gravitational search algorithm (GSA) and maintain the distribution diversity of Pareto optimal solutions. Moreover, a parallel computing strategy is introduced to improve the computational efficiency. Finally, the proposed MGSA-NSGA-III is applied to a typical hydro-thermal-wind system to verify its feasibility and effectiveness. The simulation results indicate that the proposed algorithm can obtain low economic cost and small pollutant emission when dealing with the SHTW-EED problem. [ABSTRACT FROM AUTHOR]

Sustainable development and environmental protection are key concepts in the European energy policy. The Europe 2020 Strategy establishes the necessity of reducing environmental pressure and resource consumption to increase sustainable development in the EU. In this context, the aim of this paper is to develop an Environmental and Resource Pressure Aggregated Index that considers these two dimensions. This index provides information about the achievement of the targets in the member states as well as the achieved effects of the environmental policies on energy policy and sustainable development. Therefore, it would help policy-makers to plan future policy actions. The results show that, among EU countries, Portugal, Latvia, Italy, Austria and France have low environmental and resource pressure. Recommendations are made for member states with the worst results (Estonia, Poland, Cyprus, Czech Republic and Luxembourg) in order to improve their actions in climate change and energy policy. [ABSTRACT FROM AUTHOR]

Given the self-declared energy and environmental protection objectives of many car manufacturers responsible companies must use energy-efficient production technologies. The running costs of production sites are a decisive factor in the overhead of automotive production. Therefore, it is important for many operators to reduce those costs in a sustainable way. For this purpose, they attempt to reduce both the energy consumption costs and CO 2 emissions of production systems. However, most components of the energy costs are determined during the very early phases of the product creation process. To achieve an estimation of the energy consumption in this early planning stage, a new suitable forecasting method is required. Therefore, this paper presents an approach for determining the prospective energy consumption by using Methods-Energy Measurement combined with defined energy reference cycles for manufacturing technologies. With this approach, key performance indicators are defined, and the production technologies are divided into basic energy consumers. The average energy values will be determined empirically by using the defined energy reference cycles. With these data, the energy demands for different scenarios are calculated. Thereby, it is possible to estimate the potential energy consumption of complex manufacturing cells. The designed method is validated within a case study of a modern automotive body shop. In summary, the approach contributes to identify and realize sustainable solutions in advance and thus increase the profitability of a factory. [ABSTRACT FROM AUTHOR]

Renewable energy is an important factor in achieving a low-carbon economic development path in China. This paper investigates the factors influencing renewable electricity consumption in China. Specifically, the factors that influence the share of renewable electricity in total electricity consumption in China is investigated using data from 1980 to 2011 and employing the Johansen cointegration technique and vector error correction model. The result of the analysis shows that there is a long run relationship between renewable electricity consumption and GDP per capita, trade openness, foreign direct investment, financial development and share of fossil fuel in energy consumption. Economic development and financial development promotes renewable electricity consumption while foreign direct investment, trade openness and the lobby of conventional energy sources undermine the share of renewables in total electricity consumption in China. While the effects of shocks to the other variables appear to die out over time, the “lobby effect” is persistent and explosive. The results also show that there is a uni-directional short run causality from financial development to renewable electricity consumption and from renewable electricity consumption to trade openness. The Chinese government should pursue policies that not only increase the amount of renewable electricity, but also increase the share of renewables in total electricity consumption. [ABSTRACT FROM AUTHOR]

With the rising demand for renewable energy and environmental protection, anaerobic digestion of biogas technology has attracted considerable attention within the scientific community. This paper presents a comprehensive review of research achievements on anaerobic digestion developments for biogas production. The review includes a discussion of factors affecting efficiency (temperature, pH, C/N ratio, OLR and retention time), accelerants (greenery biomass, biological pure culture and inorganic additives), reactors (conventional anaerobic reactors, sludge retention reactors and anaerobic membrane reactors) and biogas AD processes (lignocellulose waste, municipal solid waste, food waste, livestock manure and waste activated sludge) based on substrate characteristics and discusses the application of each forementioned aspect. The factors affecting efficiency are crucial to anaerobic digestion, because they play a major role in biogas production and determine the metabolic conditions for microorganism growth. As an additive, an accelerant is not only regarded as a nutrient resource, but can also improve biodegradability. The focus of reactor design is the sufficient utilization of a substrate by changing the feeding method and enhancing the attachment to biomass. The optimal digestion process balances the optimal digest conditions with the cost-optimal input/output ratio. Additionally, establishment of theoretical and technological studies should emphasize practicality based on laboratory-scale experiments because further development of biogas plants would allow for a transition from household to medium- and large-scale projects; therefore, improving stability and efficiency are recommended for advancing AD research. [ABSTRACT FROM AUTHOR]

Fast depleting fossil fuels and the growing awareness for environmental protection have led us to the energy crisis. Hence, efforts are being made by researchers to investigate new ways to extract energy from renewable sources. ‘Microgrids’ with Distributed Generators (DG) are being implemented with renewable energy systems. Optimization methods justify the cost of investment of a microgrid by enabling economic and reliable utilization of the resources. This paper strives to bring to light the concept of Hybrid Renewable Energy Systems (HRES) and state of art application of optimization tools and techniques to microgrids, integrating renewable energies. With an extensive literature survey on HRES, a framework of diverse objectives has been outlined for which optimization approaches were applied to empower the microgrid. A review of modelling and applications of renewable energy generation and storage sources is also presented. [ABSTRACT FROM AUTHOR]

Rapidly growing cities and human activities change the environment and are accompanied by some drawbacks. Sustainable remedies are needed to protect the environment and the earth against warming environment, pollution, natural resource use and other negative aspects of human activities. Applying vertical greenery systems not only reduce temperature, but also have many economic, environmental and social benefits. This review is about vertical greenery systems description, division and benefits with a focus on energy related topics. The paper describes different experiments on vertical greenery systems by attention to their energy characteristic from recent years. Scan research and studies have determined positive aspects of these sustainable systems as well as a few negative aspects. Moreover, different parameters which are involved in thermal performance of vertical greenery systems are highlighted. Based on various scan research some recommendations for future studies are proposed. [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]

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]

As a clean, renewable energy source with low carbon content, geothermal energy has the advantages of wide resource availability coverage, low environmental impact, low operating costs, and high reliability. For the development and production of more sustainable energy, geothermal energy has become one of the key areas of development in many countries. Geothermal resources are abundant in China and mainly distributed in the eastern region where the energy demand is the highest; therefore, the resources have the advantage of local development and consumption, which can alleviate the mismatch between resource distribution and demand in China's eastern and western regions. However, the development of geothermal energy started relatively late in China and has confronted many difficulties. This paper summarizes the status of geothermal energy in China and analyzes the existing problems with respect to policies and regulations, technological development, financial investment, and environmental protection. Some policy recommendations are put forward for promoting geothermal energy in China. This paper argues that the period of the "13th Five-Year Plan" is the opportunity for geothermal energy development. With the attention increasing, a series of policies to promote the development and utilization of geothermal energy could be introduced, and this resource could experience scaled development in China. • A review of China's geothermal energy reserves and development status is proposed. • Related policies and regulations, development goals and trends of geothermal energy are summarized. • The main problems of geothermal energy development and utilization in China are analyzed. • The policy recommendations aimed to solve the problem are proposed. [ABSTRACT FROM AUTHOR]

For the isolated island micro grid, a safe and reliable energy supply system is indispensable. Generally speaking, the power generation modules of an small and medium-sized isolated island energy system with off-grid power supply mode mainly include diesel generator(DIG) and distributed power supply. In order to smooth the power output fluctuation of wind and solar, coordinate the output of multiple energy generation technologies, and increase the penetration rate of distributed energy, it is necessary to develop a flexible and reliable energy system, and an efficient and smart scheduling strategy. In this paper, the power-to-gas (P2G) technology is introduced to construct a multi-energy complementary integrated energy system with deep coupling of power-gas network. Four possible game planning models are proposed by using game theory analysis method, and the energy scheduling strategies under each game mode are obtained by particle swarm optimization(PSO). By comparing the scheduling strategies under the four game modes, it can be found that the synergistic response of hydrogen and methane in the alliance cooperative game mode has absolute advantages in reducing the curtailment rate of wind and solar energy, balancing the income of each participant, improving the total income of the system, and saving energy and environmental protection. • A multi-energy complementary electric-gas coupled model containing five kinds of generators is established. • Four possible game modes are proposed. • Optimization of electrical load and gas load scheduling strategies for an isolated island microgrid. • Uninterrupted electricity and gas supply assured from the analysis. • The penetration rate of distributed renewable energy are improved and the share of diesel generator power is reduced. [ABSTRACT FROM AUTHOR]

A global goal is to call for common solutions to the challenge of environmental conservation. The cheap, clean and green energy and processes help to beat the hazardous pollution of plastics. An action of the STEP (Solar Thermal Electrochemical Process) on the polymer is to create a novel vision of the depolymerization of plastics to generate valuable fuels plus abundant hydrogen. In this paper, a solar thermo-coupled electrochemical system was first designed and employed to realize the plastics depolymerization to useful fuels for enhanced the solar utilization and the chemical polymer conversion. Exemplified by polypropylene (PP), the plastics were efficiently converted to light fuel and hydrogen via the solar-driven electrolysis coupled with pyrolysis. The results demonstrated that the depolymerization temperature was greatly lowered compared to conventional pyrolysis. The STEP conversion rates increased with a lift of the temperature and current. The high total conversion rate was significantly achieved by reaching 68.48% at 350 °C, including the solid phase of 31.52%, the liquid phase of 7.85% and the gas phase of 60.63% (w/w), which was compared to the 28.39% of the sole pyrolysis. The hydrogen was evolved during the process in the final volume of 72.5 ml, which was about 9.3 times more than that of the pyrolysis at 400 °C. In the outdoor experiments, the total conversion reached 66.64% at 350 °C, which was compared to 26.37% of the pyrolysis only. The light hydrocarbons were richly produced in the distribution of C 1 –C 5 hydrocarbons while only tiny amounts of methane and ethane were probed in the pyrolysis. The common mechanism and pathways can be tentatively proposed in a mode of the radically initiated thermochemical reactions and electrochemical redox by the induction of the solar thermo-coupled electrolysis. • The STEP plastics depolymerization was firstly created and studied. • The depolymerization was driven by the solar thermochemical-coupled electrochemical processes. • The STEP plastics depolymerization largely reduced the reaction temperature. • The STEP conversion rates were more significantly improved compared to the one of the pyrolysis. • The STEP depolymerization efficiently yields abundant hydrogen and light hydrocarbons. [ABSTRACT FROM AUTHOR]