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Under the dual pressure of energy consumption and environmental pollution, mankind hopes to develop clean and renewable alternative energy, and the rapid development of fuel cells meets people's demand for energy-efficient power systems. The emergence of portable micro energy systems represented by microfluidic fuel cells, such as paper-based microfluidic fuel cells, has greatly enriched the means of medical detection to better cope with the threat of disease transmission. In this work, the numerical simulation method is innovatively introduced to study the paper-based microfluidic fuel cells. Both transient and steady-state modes are employed to demonstrate the whole operation process of the paper-based microfluidic fuel cell. In addition, the different structural parameters, including electrode spacing, the distance between electrode and inlet, channel thickness, and electrode length, are also investigated their influence mechanisms on cell performance. Results show that the increase of most structural parameters decreases cell output power in different degrees. Even on the premise that increasing channel thickness has a positive impact on the output power, the fuel utilization still shows a downward trend. These conclusions provide theoretical support and reference for future optimization work and accelerate the development of microfluidic fuel cells. • Numerical simulation is employed to study paper-based microfluidic fuel cell. • The effects of structure parameters on cell performance are discussed. • Through fuel concentration distribution to reveal cell performance mechanism. • Fuel utilization is used to evaluate energy efficiency. [ABSTRACT FROM AUTHOR]

The measures needed to limit global warming pose a particular challenge to current fossil fuel exporters, who must not only decarbonise their local energy systems, but also compensate for the expected decline in fossil fuel revenues. One possibility is seen in the export of green hydrogen. Using Algeria as a case study, this paper analyses how different levels of ambition in hydrogen exports, energy efficiency and fuel switching affect the cost-optimal expansion of the power sector for a given overall emissions reduction path. Despite falling costs for photovoltaics and wind turbines, the results indicate that in countries with very low natural gas prices, such as Algeria, a fully renewable electricity system by 2050 is unlikely without appropriate policy measures. The expansion of renewable energy should therefore start early, given the high annual growth rates required, which will be reinforced by additional green hydrogen exports. In parallel, energy efficiency is a key factor as it directly mitigates CO2 emissions from fossil fuels and reduces domestic electricity demand, which could instead be used for hydrogen production. Integrating electrolysers into the power system could potentially help to reduce specific costs through load shifting. Overall, it seems advisable to analyse hydrogen exports together with local decarbonisation in order to better understand their interactions and to reduce emissions as efficiently as possible. These results and the methodology could be transferred to other countries that want to become green hydrogen exporters in the future and are therefore a useful addition for researchers and policy makers. • The required strong capacity expansion for PV and wind is challenging, but feasible. • "Energy efficiency first" benefits both the local energy transition and H2 exports. • Fully renewable power systems require a suitable political framework. • Higher hydrogen exports might help to reduce the specific power system cost. • Fossil capacity expansion must be stopped to avoid lock-ins and higher future costs. [ABSTRACT FROM AUTHOR]

The motivation of this paper is to investigate the resistance of countries' energy research and development (RD&D) expenditures to random shocks. The analysis includes the five countries (France, Germany, Japan, the United States, and the United Kingdom) that are the biggest investors in RD&D in fossil fuels, renewables, energy efficiency, and nuclear energy. Thus, economies will be able to take precautions against global shocks in producing sustainable energy policies. To achieve this aim, this paper uses the artificial neural network approach, which uses a distributed computing model that can store and generalize data after a learning period. Empirical results widely depend on countries and distinct energy technology policy fields. The key findings provide evidence that RD&D expenditures, except for renewables, do not tend to mean revert. The economies of Japan, Germany, and the United States should make more renewable investments to reduce the resistance of renewable energy sources to shocks and thus produce policies for both environmental sustainability and energy security. The economies of France and the United Kingdom can ensure energy security by continuing their sustainable energy policies. • Applied SDG policies focused on energy technology RD&D are presented. • The stochastic characteristics of energy technology investments are examined. • Carbon-reducing policies are recommended for the top five economies. • Energy technologies are perused through artificial intelligence approach. [ABSTRACT FROM AUTHOR]

This study analyzes the impact of green finance and renewable energy on energy efficiency in E−7 economies. We analyzed the nonlinear and asymmetric effects of green finance and renewable energy on energy efficiency. We collected data from 1985 to 2017 and applied the NARDL and 2SLS methods. The results reveal that the differences in green finance development in the E−7 region are as follows: China (0.61), Brazil (0.55), India (0.53), Indonesia (0.49), Mexico (0.37), and Russia (0.39). In 2019, the Gini coefficient was the largest in Russia (0.57), followed by Turkey. Based on empirical findings, the largest barrier to green energy efficiency is insufficient private and governmental investment in the energy sector to improve access to power, to increase energy security and promote economic growth in an environmentally sustainable manner. The findings point to a promising but vulnerable future for renewable energy and energy efficiency deployment in E−7 countries. This paper emphasizes that green financing and renewable energy policy limitations must be addressed to realize the funding potential of energy efficiency in E−7 countries. • We have analyzed the barrieres for renewable energy and energy efficiency. • Non-linear and asymmetric effects is observed on energy efficiency. • We have applied NARDL model to examine the relationship among variables. [ABSTRACT FROM AUTHOR]

• Analyzes South Asia's energy trilemma balancing energy access, security and sustainability. • Focuses on four major regional countries: India, Pakistan, Bangladesh, and Sri Lanka. • Identifies major challenges as lack of energy access, unreliable gird, and unaffordable prices. • Explores the prospects of renewable energy as the key toward a sustainable energy transition. • Presents stakeholder perspectives on crucial dynamics of energy transition. To address the faced challenges – i.e. rapidly growing energy needs, depleting fossil fuel reserves, surging energy prices, risks to security of supplies, and climate change – the World is targeting a sustainable energy transition. This energy transition is primarily propelled by a global decarbonization drive. South Asia, a developing region housing over 23% of the global population, faces the additional challenge of serious energy deprivation. The subject of energy transition has not been explored in the South Asian context in terms of drivers, challenges, and prospects. This paper investigates the prospects of sustainable energy transition in South Asia in terms of resources, consumption trends, and challenges encountered by countries in the region, particularly India, Bangladesh, Pakistan, and Sri Lanka. It also examines the sustainable and renewable energy options for the region. An original stakeholder survey provides salient behavioral insights into awareness, attitudes and opinions shaping societal response to energy transition. The findings of the study highlight the serious energy security issues faced by the region in terms of lack of access, inconsistent supplies, unreliable grids, and high energy prices. Renewables like solar energy, wind power, and hydropower have the potential to propel regional countries to energy and environmental sustainability. "Lack of consistent policies and regulations", "lack of political will" and "lack of investment" are found to be the three most important challenges to the energy transition. [ABSTRACT FROM AUTHOR]

In recent years, the severe environmental degradation and high levels of fossil fuel consumption linked to conventional ship energy systems have drawn attention to the advancement of alternative ship energy systems. Consequently, ship energy systems based on the use of an electrical microgrid are coming to the fore as an increasingly popular alternative solution. However, managing the energy flows within a shipboard microgrid can be highly challenging due to the multiple energy sources (including renewable energy sources) and types of loads involved. Additionally, the integration of an energy storage system has been identified as an effective solution for improving the reliability of shipboard power systems, pointing out the important role of energy storage systems in maritime microgrids and their potential to enhance the energy management process. As such, effective energy management strategies are necessary to optimize performance and ensure that the vessel's energy demands are met while minimizing fuel consumption and reducing cost and environmental impacts. This paper presents a comprehensive review of such strategies and methods recently presented in the literature associated with energy management in shipboard microgrids integrating energy storage systems and examine the different techniques that can be utilized to achieve optimal system performance. Moreover, the paper also sheds light on the future challenges and perspectives imposed by the modern shipboard microgrids operation on the energy/power management of these systems. The aim of this paper is to provide a helpful guideline for researchers and engineers conducting research in the field of electrically powered ships. [Display omitted] • A comprehensive review of EMS for electrical and hybrid ship is presented. • A comprehensive review of ESS which can be used in such ships is presented. • Technologies of ESS and their suitability to ships are discussed and commented. • Future challenges and perspectives imposed by modern SMG operation are presented. [ABSTRACT FROM AUTHOR]

The energy needs of a Net Zero Energy Building (NZEB) are fully met by renewable energy sources. Nevertheless, the time span of the energy balance can affect the effective energy self-sufficiency of the building. The aim of this paper is to demonstrate the lack of reliability that a yearly energy balance has in characterizing an NZEB. At this scope, comparisons between two different photovoltaic systems (fixed and tracking) and two kinds of energy balance (yearly and monthly) are made for a real NZEB building located in South-Italy. The investigation was carried out through dynamic energy simulations after validating the building model. The results show that the PV surface which attains the NZEB target on yearly basis not always achieves the same objective as the monthly balance. Furthermore, considering a monthly balance, the size of the photovoltaic system with biaxial solar tracking is 50% minor than the fixed one, thanks to a steadier energy production. Also, solar tracking systems show a significantly lower reduction of operational and embodied CO 2 emissions. A final technical-economic analysis shows, however, that design solutions that satisfy NZEB target not always can meet the financial interest of the private stakeholder, showing a high discounted payback period. • The energy needs of an existing NZEB are evaluated through dynamic simulation. • Fixed and tracking PV systems are designed and compared to obtain the NZEB target. • Comparisons between yearly and monthly balance using different PV systems are made. • Yearly balance is not adequate to characterize energy self-sufficiency for an NZEB. • Tracking PVs reduce monthly withdrawal from electricity grid and CO 2 emissions. [ABSTRACT FROM AUTHOR]

As the world's largest energy consuming country, it is important to study the mechanisms of improving renewable energy and energy efficiency to achieve green economic growth in China and globally. Therefore, this study investigates the impact of environmental regulations on green economic growth and renewable energy development in China, respectively. First, this study measures the level of green economic growth in Chinese cities by the Metafrontier-Global-SBM super-efficient data envelopment analysis (DEA) model from the perspective of energy efficiency. And the environmental regulation intensity was measured using an improved fuzzy comprehensive evaluation method. Second, a spatial econometric model based on longitudinal data was constructed to examine the non-linear effects of environmental regulations on green economic growth and its spatial spillover and feedback effects. The results indicated a U-shaped non-linear effect of energy efficiency-related environmental regulation on green economic growth as well as a spatial spillover effect and spatial feedback effect. Finally, the impact of environmental regulation on renewable energy development was investigated. The results show that renewable energy development, an important component of green economic growth, is equally dependent on the implementation of environmental regulation policies and that environmental regulation makes a significant contribution to renewable energy development. The findings of this paper provide a basis for the realization of green economic growth and the formulation of renewable energy policies in China. • Impact of environmental regulation on renewable energy development was investigated. • A spatial econometric model of 286 Chinese cities from 2003 to 2018 was constructed. • Environmental regulation has a significant U-shaped effect on green economic growth. • Non-linear effects include spatial spillover and spatial feedback effects. • Environmental regulation promotes green growth earlier in resource-based cities. [ABSTRACT FROM AUTHOR]

The possibility to upgrade biomass and intermittent power from renewable energy sources generating stable power and substitute natural gas (SNG) has been discussed in previous papers. Such papers focussed mainly on the choice and design of the most suitable power units to generate power and a high purity carbon dioxide stream to feed the methanation section; moreover, heat recovery strategies to improve the plant efficiency were investigated and implemented. In the proposed plant, power for electrolysis potentially comes from renewable energy sources (RES), thus arises the need to introduce gas storages in order to fully decouple the outputs (SNG flow and stable electric power) from the input intermittency. This paper analyses some different possible layouts for intermediate gas storages and compares them from an energy consumption point of view. • A continuous SNG production from intermittent RES is achieved. • Several gas storage configurations are modelled and compared. • Optimal waste heat recovery solutions prevent storages from penalising efficiency. [ABSTRACT FROM AUTHOR]

Highlights • The paper presents an overview of the main challenges that affect EU power systems due to the penetration of cleaner and distributed resources. • The first part of the paper describes the changes that are occurring in the power system and market sector. • The second part of the paper presents the challenges in the Eu-wide planning process. Abstract In the past, much of Europe's electricity grid network has been designed in consideration of the locations of conventional generation plants. However, a large share of today's renewables production – notably variable wind and solar – does not correspond to this grid architecture. Interconnectors, in addition to internal infrastructure, are key to creating new electricity corridors to connect areas of surplus to areas of scarcity. In this context, in 2014 the European Council, in recognizing that a fundamental role of transmission infrastructure is to enable the integration of areas of high renewable energy potential with main consumption areas, endorsed the proposal by the European Commission to extend the current 10% electricity interconnection target to 15%. In this way, more available interconnection capacity would enable the grid to accommodate such increasing levels of variable renewable generation in a secure and cost-effective way. The previously described changes in interconnected system operating conditions, resulting in potential occurrences of unforeseen serious disturbances – most notably the well-known system split observed in the continental synchronous area on 04 November 2006 – have led to create the first Regional Security Coordination Initiatives (RSCIs now RSCs) and establishment of Coreso and TSC back in 2008. These entities have allowed TSOs to further coordinate not only system operations but also network planning, system adequacy analysis, market setups, etc. However, given the challenges faced by the electricity industry in Europe, one may wonder whether the pace of developments in regulation and market design, system operations and system planning can keep up with the pace of change in the electricity system. In response to this concern, the present paper focuses on a central question: how the electricity system that is today primarily organized in a centralized, top-down manner will be reshuffled in the future? The structure of the paper is as follow. The authors begin by describing the changes that are occurring in the power system and market sector, together with their drivers and underpinning regulation. Then the paper presents the challenges in the Eu-wide planning process, starting from TYNDP and PCI and then proceeding also to technical aspects of cost-benefit analysis and interconnection targets. [ABSTRACT FROM AUTHOR]

Plug-in hybrid electric vehicles (PHEVs) have received a lot of interest because of their ability to cut fuel usage by using electricity from the grid as an alternative energy source. PHEVs differ from typical hybrid electric vehicles (HEVs) in terms of increased battery capacity, the availability of plug-in recharging, and improved battery state of charge (SOC) management systems. Efficient energy consumption and excellent performance are critical issues for hybrid powertrains. The estimation of SOC in PHEVs is a difficult NP-hard problem that is frequently tackled utilising metaheuristic techniques. In this paper, we offer an enhanced dingo optimisation with deep learning-based prediction (EDOA-DLP) model specifically tailored for PHEVs. The EDOA-DLP model includes an efficient SOC estimate algorithm for real-time energy management. The EDOA-DLP technique's performance has been thoroughly proven through considerable experimentation in a variety of circumstances. The results show that the proposed EDOA-DLP method beats other current methods in terms of predicting SOC accurately and reaching the targeted goals for PHEVs. Overall, this research presents a unique EDOA-DLP SOC prediction approach for PHEVs, with promising results in terms of energy management and performance optimisation. The experimental results highlight the EDOA-DLP model's improved performance. Overall, this research presents a unique EDOA-DLP SOC prediction approach for PHEVs, with promising results in terms of energy management and performance optimisation. The experimental results illustrate the EDOA-DLP model's improved performance when compared to competing methodologies, highlighting its potential to improve the efficiency and efficacy of PHEV systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Feasibility of using organic wastewater as renewable energy source is verified. • ＞99% COD, TOC removal rate in the experimental platform. • Up to 78.75% of the energy recovery efficiency of the SCWO system. The degradation of high concentration organic wastewater and the recovery of energy using supercritical water oxidation (SCWO) technology have the potential to become viable in the future. High concentration organic wastewater contains a significant amount of energy. This paper focuses on utilizing high concentrated wastewater as a renewable energy source, from an energy system perspective, an experimental rig was designed to determine the optimal working conditions. The experiments were conducted with an oxidation coefficient of 1.1, a flow rate of high concentration organic wastewater of 9 ml/min, a heating temperature of 400 °C, and a reaction pressure of 25 MPa. Under these conditions, the COD and TOC removal rates of the high concentration organic wastewater were found to be 99.383 % and 99.876 % respectively. Additionally, the phenomenon of "Abnormalities in pressure sensitivity" observed during high concentration organic wastewater the experiment was further explained through additional experiments. Finally, by comparing the experimental energy recovery with the simulation results, an energy recovery efficiency of 78.95 % was achieved. The feasibility of the simulated energy recovery in practice was verified, confirming the potential to convert the previous energy-consuming wastewater treatment process into a productive one. This study provides a theoretical and experimental foundation for further related research. [ABSTRACT FROM AUTHOR]

During its operation, a photovoltaic (PV) panel is exposed to various and in general, stochastic thermal and wind conditions, which have a significant influence on the PV panel operating temperature. The increased PV panel operating temperatures normally have an unfavorable effect on the PV panel performance and lifetime, thus various cooling methods were proposed in order to increase the photovoltaic energy conversion efficiency. A reasonable step before the consideration of a specific cooling strategy is to obtain a PV panel performance analysis with respect to its surroundings (specific geographical micro location) for various operating conditions. This paper presents such a study, which was conducted through an experimentally validated numerical model. Numerous CFD simulations regarding heat and fluid flow around a monocrystalline PV panel coupled with a heat flow simulation inside the PV panel elements were conducted. The aim of the paper was to investigate an effective heat transfer field and the variations in the PV panel temperatures with respect to various wind velocities and heat source conditions. A detailed study regarding pressure, viscous and body (buoyancy) forces as well as their effects on flow separation was also conducted. The study also investigated the changes in the effective heat transfer near the PV panel. The gained results in this study turned out to be useful for the consideration of a specific cooling strategy for PV panels, which can ultimately lead to an increase in PV panel efficiency and lifetime. Additionally, the conducted study could be used to improve the delivered electricity prediction from the PV system at a selected location defined by specific wind velocities and solar insolation distributions. [ABSTRACT FROM AUTHOR]

This paper presents the editorial for the Renewable and Sustainable Energy Reviews joint special issue devoted to the research work discussed and presented at the 11th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES), held from the 4th September to the 9th September 2016 in Lisbon, Portugal and the 2nd South East European (SEE) SDEWES Conference held from June 15th to June 18th, 2016 in Piran, Slovenia. This special issue is in line with the journal's aim of publishing research from across the ever-broadening field of renewable and sustainable energy with a strong review element. Previous SDEWES conference special issues have gathered a significant knowledge base in the field of sustainable development that reflects the continuous research efforts of the SDEWES research community. Therefore, this editorial provides not only an overview of the papers published in this particular special issue, but also a wider overview of the current trends in the domain of sustainable and renewable energy. This year's special issue focuses particularly on the benefits of the bio-based economy, energy security issues, fossil fuel thermal plant alternatives and environmental constraints, district heating and cooling together with cross sector energy efficiency and energy conservation issues. Sustainable transport systems, the issue of fuel poverty in urban neighbourhoods and renewable energy to support development of peripheral rural areas, optimising passive building design for hot climates and solar-powered heating and cooling are further topics featured in this special issue. In the process of selecting papers for this special issue, the guest editors invited in total 23 extended manuscripts for consideration for publication. After a rigorous review process by expert reviewers overseen by the guest editors a total of 16 articles were accepted for publication. [ABSTRACT FROM AUTHOR]

Industry poses one of the biggest challenges in the renewable energy transition. In this paper, fossil fuels in the European industrial sector are replaced by renewable energy using a novel tool, IndustryPLAN, a planning tool for the assessment of national industrial sectors. In a bottom-up approach, each industry sub-sector is addressed with energy efficiency and fossil fuel replacement measures based on best available and innovative technologies, and in a top-down approach, the fuel and electricity consumption per country is analysed and decarbonised. The results indicate that: 1. Known technologies can decarbonise most of the industrial sector; 2. Costs and efficiencies are improved by energy savings and electrification; 3. Limiting bioenergy consumption is a critical challenge, emphasising the key role of energy savings and electrification, and the alternative of using hydrogen or hydrogen-based electrofuels will make the transition more expensive and induce energy losses. A full transition to renewable energy and a decarbonised industry sector may be possible before 2050, however, this requires that all investments are sustainable from 2030 onwards and that grid electricity is fully decarbonised. This paper presents several pathways toward 100% renewable energy supply in the European industrial sector and discusses the implications of the outlined scenarios. • Four tangible 100% renewable energy scenarios for industry in EU27 + UK are established. • 100% renewable energy in industry is feasible before 2050. • Energy efficiency improvements are essential to limit biomass consumption. • Industry energy transition needs to be prioritised in short- and long-term planning. [ABSTRACT FROM AUTHOR]

The paper addresses the assessment of the Stirling engine performance by comparing biomass and solar energy as external renewable energy sources. A program-code was developed in the MatLab® to solve the thermal model of an alpha-Stirling engine, accounting for the limitations in the heat transfer processes in the regenerator and the losses due to pumping effects. The solar energy source was modelled as a concentric solar dish collector, considering a receiver located at the focal point and designed to absorb the maximum possible of the solar radiation. Regarding the biomass system, the temperature of the flue gases leaving the bed is computed through an energy balance, considering the fuel energy introduced into the bed, the energy that is provided by the bed and the incident radiation in the bed. The simulation results show that the biomass-fuelled Stirling engine provided 87.5% more power output than the solar energy source, with an efficiency of 46.67%. Also, the average receiver temperature from the solar source is about 775 K, whereas, in the boiler bed, the temperature reaches the value of 1288 K. In the solar-dish modelling, the reflected radiation that passes into the cavity receiver depends on the aperture ratio and rim angle. It was proved that a rim angle of at least 45° is required to ensure lower focal distances. Otherwise, the Stirling receiver needs to be far from the surface of the dish, resulting in higher thermal losses and lower temperature inside the receiver cavity. In biomass-fuelled system, it was shown that the temperature of the flue gases increases with the increasing the radiation flux, and decreases for higher split percentages between the primary and secondary air. The study also revealed the need to investigate the combustion stability regarding the particle emission in the flue gas, which can reduce the temperature close to the hot cylinder of the Stirling engine. The LCoE for the solar-power system is of about 1658 €/kWh, which is 52% higher when compared with the biomass-fuelled system (0.109 €/kWh). In conclusion, biomass-fuelled Stirling engines are able to provide a higher power output with higher thermal efficiency, avoiding the problems usually related to solar energy intermittency. Image 1067 • The solar energy source was modelled as a concentric solar dish collector. • A bed model was developed to predict the flue gas temperature. • The biomass-fuelled Stirling engine provided 87.5% more power output than the solar. • The solar dish Stirling produces 2.3 kW of power with an efficiency of 31.3%. • The biomass-fuelled system produces 4.3 kW of power with an efficiency of 46.7%. [ABSTRACT FROM AUTHOR]

The paper focuses on the use of heat generated during a chemical reaction as an alternative source of environmental energy. Exothermic reaction heat in the presence of light chemical elements have been studied. The heat of these reactions is summed up by the heat of combustion of hydrogen. Therefore, the effectiveness of alternative energy sources increases significantly. Electrochemical and mixed (electrochemical + carbo-thermal) methods have been developed to restore the starting components from the reaction products. The energy efficiencies of the electrochemical and mixed methods were calculated giving (without using the heat of exothermic reaction heat) 47.4% and 74%, respectively, whereas using the heat of exothermic reactions, energy efficiency is 82% and 99%, respectively. In general, for 1 kg of magnesium in the five-step electrochemical process 21012 kJ of heat are released, 165 g of hydrogen and one cubic meter of oxygen are formed. The mixed method produces 247 g of hydrogen and 21065 kJ of heat. • The 5-step cyclic chemical methods for hydrogen production have been developed. • Investigation allows one to control and increase the energy efficiency of H 2 production. • Heat of 247 g H 2 + heat of chemical reactions exceeds heat of 1 kg any fuel. [ABSTRACT FROM AUTHOR]

Thermal grids will play a key role in the development of local energy communities and the achievement of 100% renewable societies. Such systems allow excess heat produced by distributed producers through renewable energy sources (also referred to as "thermal prosumers") to be shared among other consumers characterized by high heat demand or who still depend on fossil fuels. However, to achieve more reliable results when performing energy analyses, it is of utmost importance to develop models of prosumers' substations, where technical details (e.g., type of connections, heat exchangers, valves, etc.) and controllers are accounted for. Starting from the layout of a bidirectional substation for a thermal energy network proposed in the literature, this paper proposes a dynamic model that replicates the experimental setup in the TRNSYS environment. Validation results show a good matching between simulation and experiments in terms of dynamic behavior and energy balance. To show the capabilities of the proposed model, a prosumer with heat available from 205 m2 solar thermal collectors is considered as a case study. The analysis is performed by assuming two locations characterized by different irradiation values, i.e., Palermo (Italy) and Berlin (Germany). The results show that exchanging the excess heat produced on-site with a heating network allows the solar collectors to reach peak heat production, which is 130 kW and 110 kW for Palermo and Berlin, respectively. The surplus heat sold to the network is equal to 66% and 29% of the total energy exchange within the substation for Palermo and Berlin, respectively. Conversely, the self-consumption of the produced heat accounts for 21.2% and 30.6%, respectively. The model prospectively represents a valuable tool to develop feasibility studies in Thermal Energy Communities and assess the potential of innovative energy- and cost-effective operation strategies. • A model of a thermal prosumer substation exchanging with a District Heating Network (DHN) was created in TRNSYS • The virtual model was validated through experimental data by showing a good matching between simulation and experiments • To show the capabilities of the model, a prosumer equipped with 205 m2 solar thermal collectors is considered as a case study • Results showed that the prosumer substation allowed for optimal exploitation of the heat produced by the solar collectors • The proposed model represents a viable tool to perform analyses applied to renewable energy systems in prosumers networks [ABSTRACT FROM AUTHOR]

The Sustainable Development Goal (SDG) that emphasizes sustainable and affordable energy presents a practical pathway to achieve sustainable growth. Moreover, this goal aligns with SDG 13, which focuses on climate action. Nonetheless, it is important to consider factors such as political and financial risk, as they can influence climate action efforts and the renewable energy sources adoption. Hence, this study broadens the conversation surrounding CO 2 emission reduction and the achievement of Sustainable Development Goals (SDGs). It accomplishes this by investigating the interplay between renewable energy, political risk, financial risk, and CO 2 emissions in Finland spanning from 1990/Q1 to 2021/Q4. Notably, this research distinguishes itself through its exploration of these complex connections, employing a wavelet-based quantile methodology. Unlike traditional quantile regression, which can only reveal connections between variables within each quantile, the wavelet-based quantile approach enables the simultaneous capture of correlations across quantiles and periods. The results show that in the long-term and across all quantiles (0.01–0.99), energy efficiency, specifically gas and oil efficiency, lessens CO 2. In addition, low financial and political risks improve ecological quality by lessening CO 2 across all periods and quantiles (0.01–0.99). The paper outcomes serve as a basis for formulating a policy framework aimed at achieving SDG 7 and SDG 13 in Finland. • We explore the impact of energy efficiency and country risk on CO 2 emissions. • The role of renewable energy and economic growth are also analyzed. • The Time series data of the Finland is used from 1990/Q1 to 2020/Q4. • Various wavelet-based quantile correlation is applied. • Renewable energy, oil and gas efficiency decrease CO 2 emissions in each quantile and across periods. [ABSTRACT FROM AUTHOR]

Environmental degradation has become one of the major challenges facing the global community. This paper aims to explore the more effective options to combat environmental degradation by investigating the linearity and nonlinearity (trade openness set as a threshold variable) of energy efficiency, natural gas, renewable energy and ecological footprint. To this end, linear and non-linear panel models were constructed using panel data from 60 countries. The results of the linear analysis show that improving energy efficiency, and increasing the consumption of natural gas and renewable energy are conducive to inhibiting environmental degradation. Energy efficiency has the most significant negative correlation with ecological footprint, followed by renewable energy, and then natural gas, implying that improving energy efficiency and developing renewable energy is a more effective strategy to combat environmental degradation. The results of the nonlinear analysis show that there are threshold effects of trade openness between energy efficiency and ecological footprint, and between renewable energy and ecological footprint. The negative impact of both renewable energy and energy efficiency on the ecological footprint increases when trade openness exceeds the threshold. This suggests that, in terms of curbing environmental degradation, enhancing trade openness may further increase the negative impacts of energy efficiency and renewable energy on ecological footprint. At the same time, this confirms the positive role of trade openness in environmental protection. [Display omitted] • Exploring more effective option to combat environmental degradation. • Energy efficiency, renewable energy, natural gas can reduce ecological footprint. • Trade openness help energy efficiency, renewables lower ecological footprint. • The most effective strategy is energy efficiency, followed by renewables and natural gas. [ABSTRACT FROM AUTHOR]

Policies targeting energy efficiency and renewable energy are sometimes viewed as more politically feasible than carbon pricing in pursuit of emission reduction goals. This paper assesses underlying drivers of energy policy development. These factors include economic, social, environmental, and institutional variables. The between estimator for panel data is an appropriate method for our focus on some exogenous variables that vary more across countries than over time. We find that larger oil reserves per capita have a negative relationship with renewable energy policy development. Education and political globalisation have strong positive relationships with both energy-efficiency and renewable-energy policy development. These results suggest that greater participation in global political groups can be an indirect approach toward energy policy development, in cases where direct and immediate policies are hard to implement. OECD countries have higher policy scores by 33 and 25 points in energy efficiency and renewable energy respectively. Blinder-Oaxaca decomposition analysis shows that these higher scores are primarily due to social and political institution predictors rather than economics and physical endowments. • Large-n cross country international sample on continuous policy score measurement. • Political globalisation is positively linked with renewables and energy efficiency policies. • Education is positively linked to energy policy development, especially for efficiency. • Higher OECD countries' policy scores are primarily due to social and political predictors. • Higher incomes are unlikely to lead to automatic improvements in energy policies. [ABSTRACT FROM AUTHOR]

The increasingly serious renewable generation curtailment in many countries reflects the drawbacks of current planning approach, which separates power source planning and grid expansion planning. In addition, resources in demand side should no longer be ignored in power planning with gradually mature policies related to energy efficiency and demand response. To fill this gap, this paper proposes a novel power system planning approach and builds an integrated source-grid-load planning model at the macro level. The model considers all the available elements in source side, grid side and load side together to find an optimal development solution from the perspective of the whole power system. The effectiveness and superiority of this model is verified through the comparison among separated source-grid planning, integrated source-grid planning and integrated source-grid-load planning in the case study. Then, an optimum development path for China's power sector till 2030 worked out by the model proposed in this paper is presented. Based on the in-depth analysis of the planning results, policy recommendations are also provided. [ABSTRACT FROM AUTHOR]

Excessive energy consumption and carbon dioxide emissions are long lasting issues and need continuous research to improve efficiency evaluation and performance monitoring of economies. The static and dynamic aspects of efficiency need to be dealt with simultaneously to thoroughly analyze the performance of economies. This paper aims at conducting a static and dynamic analysis of energy and CO 2 emissions efficiency of major economies. In this paper, we applied slacks based model of Tone (2001) with the treatment of undesirable output in objective function and constraint assuming free disposability of undesirable output and built a dashboard. The results can be summarized by saying that the larger economies with intensive production strategy, larger secondary industry, and weaker carbon tax laws are more likely to be inefficient. China, India, and Russia have the greatest potential for improvement in both energy efficiency and carbon dioxide emissions efficiency. The suggested dashboard has the ability to dig out the potential for efficiency improvement of countries like the USA, which mostly appear at the efficient frontier with other techniques. Concluding it can be suggested that economies in lower ranks of dashboard need stricter policy measures to cut energy consumption, carbon dioxide emissions and encourage a shift from fossil fuels to other renewable resources of energy. [ABSTRACT FROM AUTHOR]

Climate change and fossil fuel reserve depletion both pose challenges for energy security and for wellbeing in general. The top ten among them include: Decarbonising the world economy; Enhancing the energy efficiency and energy savings in buildings; Advancing the energy technologies; Moving towards energy systems based on variable renewables; Electrifying the transport and some industrial processes; Liberalizing and extending the energy markets; Integrating energy sectors to Smart Energy Systems; Making the cities and communities smart; Diversifying the energy sources; and Building more biorefineries. Presenting the contributions of selected conference papers published in the special issues of leading scientific journals (including all the papers from the current Energy special issue), this review demonstrates the capacity of the Conferences on Sustainable Development of Energy, Water and Environment Systems for generation of knowledge which could serve as the centrepiece of a pertinent response to those challenges. [ABSTRACT FROM AUTHOR]

The economic assessment of low-carbon energy options is the primary step towards the design of policy portfolios to foster the green energy economy. However, today these assessments often fall short of including important determinants of the overall cost-benefit balance of such options by not including indirect costs and benefits, even though these can be game-changing. This is often due to the lack of adequate methodologies. The purpose of this paper is to provide a comprehensive account of the key methodological challenges to the assessment of the multiple impacts of energy options, and an initial menu of potential solutions to address these challenges. The paper first provides evidence for the importance of the multiple impacts of energy actions in the assessment of low-carbon options. The paper identifies a few key challenges to the evaluation of the co-impacts of low-carbon options and demonstrates that these are more complex for co-impacts than for the direct ones. Such challenges include several layers of additionality, high context dependency, and accounting for distributional effects. The paper continues by identifying the key challenges to the aggregation of multiple impacts including the risks of overcounting while taking into account the multitude of interactions among the various co-impacts. The paper proposes an analytical framework that can help address these and frame a systematic assessment of the multiple impacts. [ABSTRACT FROM AUTHOR]

Energy efficiency policies play a key role in the transformation to a ‘green energy economy’. In this paper, we take stock of the impacts of the existing energy efficiency policy instruments in Germany and review the energy, environmental and socioeconomic impacts of the country’s latest energy efficiency and climate strategies for the year 2020. We find evidence supporting the findings of other studies that enhanced green energy policies will trigger tangible economic benefits in terms of GDP growth and new jobs even in the short term. Whereas policy makers have already acknowledged and implemented this conclusion in the case of renewable energies, our paper shows that striving for more ambitious energy efficiency policies represents a similar win–win strategy, which should be exploited to a much larger extent. [ABSTRACT FROM AUTHOR]

• Examination of a typical classroom in Greece and its installed power for an artificial lighting profile from 1970 until today (type and number of luminaires, installed power per classroom, consumed annual energy kWh/m2). • Calculation of potential energy savings for customizing installed power LED with AC and DC supply aiming for the illuminance target values from the European Norm 12464–1, 2011. • Measurements of dimming curves of LED luminaires with AC and DC supply (consumed energy versus lighting output) and measurements of power of typical photosensors. • Estimated energy savings, CO 2 reduction and cost optimal analysis due to various scenarios (different luminaire technologies and daylight harvesting techniques). • Calculation of the final energy consumption for potential power supply from renewable energy sources using DC LED luminaires and photosensors. The energy consumption for the artificial lighting in school buildings is one of the main consumers of electricity. In Greece, there is a large number of school buildings with quite old lighting systems using luminaires with T8 and sometimes T12 fluorescent lamps and degradated translucent diffusers. Due to the economic crisis, the public sector failed to invest in LEDs and although daylight is adequate during the year, the adoption of control technology is rather slow. The paper, using a typical classroom of a Greek public school, examines a number of lighting technologies (with AC and DC supply) together with two daylight harvesting systems. The first one uses one stand-alone photosensor per luminaire while the second one sensor per control zone, in an effort to calculate energy savings and light adequacy. The dimming curves of the DC LEDs were measured along with the installed power of the photosensors. The results show that the existing 90.5 kWh p /m2 of annual lighting primary energy consumption can be reduced to 0.55 kWh p /m2. The maximum annual reduction of CO 2 emissions was 32.44 kgr/m2 for classroom areas, which is translated to 201929 tn for the whole country. It is evident that the path to Zero Energy School Buildings goes through the mandatory use of daylight controls. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Abstract Although passive building envelope systems dominate contemporary building design, active building envelope (ABE) research, development, and deployment are rapidly growing and present many new ways to address building energy efficiency at the façade level. This paper presents a comprehensive review on the state-of-art-research on ABEs for improving building energy efficiency. First, a clarified concept of ABE is put forward based on two conditions: The ability of lowering cooling/heating loads in buildings, and performing energy transformation as the key judging factors. Second, four major categories of ABEs, namely air-based, water-based, solid-based and kinetic façades, are discussed in terms of their system structural and functional features as well as system performance. In addition, a statistical analysis is performed for a better understanding of current research focus, general trends, as well as research methods. It is found that technical research on ABEs has dramatically increased but the ratio of ABE to general façade studies remains stable. In terms of research methods and approaches, numerical simulations are dominant. Some specific comments on limitations of current ABE studies and general suggestions for the future studies are discussed. Future work suggests the need for contributions from a wide range of scientists, engineers, and architects in the building industry and beyond to push forward building energy efficiency. Highlights • A new and effective definition of active building envelope is proposed. • Research tendency, distributions and study methods offer a clear map of active building envelopes. • A state-of-the-art review and discussion is presented for active building envelopes. • Outlooks and recommendations for active envelopes can facilitate its further development. [ABSTRACT FROM AUTHOR]

Abstract The coupling between heat pumps and renewable energy sources is a recognized strategy to reduce primary energy consumption at the household level. This paper contributes to the present-day discussion concerning solar-assisted heat pumps for heating/cooling and to produce domestic how water. In particular, this study presents the results of a field study concerning a novel solar-assisted dual-source multifunctional heat pump, installed in a detached house in Milan. The proposed system couples hybrid photovoltaic/thermal (PVT) panels with a multifunctional and reversible heat pump. The heat pump is equipped with " air-source " and " water-source " evaporators, connected in series and operated alternatively, based on the ambient conditions, system parameters and operating modes. In addition, the PVT panels are used, by employing two storage tanks, to produce domestic hot water and to provide a heat source to the " water-source " evaporator. The proposed system has been tested experimentally, showing interesting and promising results: the system has been able to maintain high efficiencies in the different seasons and has been able to use the solar energy to support the production of domestic hot water. It was found that the use of the " water-source " evaporator allowed to significantly increase the performance of the system and to avoid the defrost cycles. Highlights • We present a novel solar-assisted dual source multifunctional heat pump. • We summarize the results of a field trial. • We provide seasonal performances of unit installed in a detached house. • We provide daily performances of unit installed in a detached house. • We relate seasonal and daily performances. [ABSTRACT FROM AUTHOR]

Highlights • Ιncreasing need for modern pricing schemes to effectively incentivize willing users to modify their energy consumption pattern. • Current energy pricing schemes do not adequately compensate for behavioral changes. • We propose a Community aware — Real Time Pricing (CRTP) scheme to reduce system's energy cost. • We propose an Energy Community Formation Algorithm (ECFA). • The proposed scheme achieves considerable reduction in the system's energy cost and greater aggregated users' welfare. Abstract The harmonization between the variable rate of energy production in the era of massive renewable energy penetration is a major challenge in an open, competitive and resilient electricity market. As a result, there is an increasing need for modern pricing schemes, which will effectively incentivize willing users to modify their energy consumption pattern to meet this objective. Current energy pricing schemes (e.g. real time pricing) treat all users the same, and do not adequately compensate for behavioral changes, thus mitigating the behavioral change dynamics. In this paper, we propose a Community Real Time Pricing (CRTP) scheme together with an Energy Community Formation Algorithm (ECFA), where users are clustered in Virtual Energy Communities (VECs) according to: (i) their level of flexibility in modifying their Energy Consumption Curve (ECC), and (ii) their relationships in Online Social Networks (OSNs), modelling peer-pressure capabilities. We show that CRTP with ECFA can simultaneously achieve considerable reduction in the system's energy cost and greater aggregated users' welfare than with the state-of-the-art real time pricing. CRTP–ECFA adopts a truly fair pricing policy, as each user is rewarded exactly according to his/her individual contribution in reducing system costs, thus promoting the desired behavioral change. [ABSTRACT FROM AUTHOR]

Ground heat exchanger takes the soil underground as heat source or sink to supply cooling or heating. It has been widely used in building heating and cooling systems due to high efficiency and environmental friendliness. This paper reviews the latest research on ground heat exchangers from several new perspectives and demonstrates their potentials in achieving zero energy buildings. Firstly, ground heat exchangers are classified into water-based and air-based ones based on the heat transfer medium. They can be used in a passive or active approach. Associated research and projects for each approach are introduced and analysed. Then the integration of ground heat exchangers with various cooling and heating technologies and related studies are reviewed. These technologies include solar thermal collectors, cooling towers, nocturnal radiative cooling technology, solar chimney, etc. Finally, a technical route for ground heat exchangers to help realize zero energy buildings is presented, which provides a promising solution to improve energy efficiency of buildings. [ABSTRACT FROM AUTHOR]

Abstract Sustainable and energy efficient transport of passengers and goods has become a major concern of policy makers worldwide. This paper examines the existence of policies and measures for sustainable urban freight transport in European cities. The methodology for comprehensive mapping and benchmarking of strategic policy documents and measures has been developed and applied to a panel of 129 European cities. The desktop analysis shows an extremely heterogeneous situation of logistics and mobility planning policies and planning documents adopted in Europe. Cities are mainly opting for soft measures with high impact on savings. They are trying to achieve efficiency with adequate regulation system and measures supporting the introduction of new services. Only few measures directly promoting energy savings were identified while on the other hand, various measures with indirect impact on energy consumption were recognised. Highlights • Literature review of urban freight transport problems, policies, measures and models. • Methodology for mapping and benchmarking strategic policy documents. • Review of strategic policy documents for a panel of 129 European cities. • Best practice examples of measures contributing to energy saving. [ABSTRACT FROM AUTHOR]

Highlights • It uses a calibration weight and adjusts the energy left at higher category user to next category user, at one substation to the next one which increases the energy distribution, nullifies the energy wastage and yields 100% distribution efficiency. • The energy distribution using the proposed schemes results very high fairness index at grid of 98%. • The energy distribution with 100% energy distribution efficiency with high fairness initiates a new research scope in future smart grid technology. Abstract For the benefit of mankind, future technologies should be eco-friendly, eschew CO 2 , be capable of smart energy generation using renewable energy sources and be effective in raising the energy efficiency of individual users. This leads to the optimization of energy generation, distribution and utility at the user level, which helps in handling demand-side management (DSM) of the smart grid effectively. The energy distribution flow in a smart grid can be modeled as a smart grid tree network (SGTN). To promote the requirement of secondary energy generation using renewable energy sources at the customer level, secondary energy generated by the customer with a load demand is included in order to calculate the energy demand on the smart grid. Depending on the load request and demand, the energy is granted for various levels of child nodes in an SGTN using load weight (LW) and demand. In this paper, thermometer approach-based energy distribution with a load (TAEDL) is proposed in order to derive energy efficiency at various levels of the SGTN. The proposed technique is refined to attain maximum energy distribution efficiency and fairness using a thermometer approach with fine calibration (FC). The total energy distributed to the users, the number of satisfied users, the energy distribution efficiency, and the fairness index (FI) of the SGTN are evaluated at various levels. The simulation results show that the suggested technique outperforms in terms of energy distribution with fairness and initiates a revolutionary change in future smart grid technology. [ABSTRACT FROM AUTHOR]

Diffusion of Renewable Energy Technologies (RETs) governs by the status of technology in terms of efficiency and techno-economical feasibility. The states plan for the deployment of resources for the development with special reference to sustainable environment. The demand and supply energy model help to provide more focus on the long term goals. The theory of diffusion modeling allows analysis of diffusion processes and study of growth rates of different technologies and underlying diffusion factors of the particular states, particularly for Indian 8 National Missions implication factors concerning to National Action Plan for Climate Change (NAPCC). The Energy Management Systems (EMS) and Distribution Management Systems (DMS) provide control on hybrid sources of energy generation and distribution over on-grid and off-grid applications. Energy Distributive system model for adequate accurate predictive analysis plays important role for sustainable country energy resources, in consideration of all influential factors in energy generation and distribution. For prediction aspects the important parameters are geographical location, seasonal influence, effect of climate change and state or area concession. With the abundant data and relative economic indicator, energy prediction is performed with close loop predictive system based of timing algorithm. The energy economics in free trade market like India, where the peak load varies abruptly due to season and community demand, its hourly prediction model is more useful. The energy model provides the estimation and prediction of hybrid power generation in consideration of the parameters on resource potential, technology, efficiency and consumption pattern. The monitor, statistical and prediction model with inbuilt mechanism for renewable energy certificate (REC) and perform, achieve and trade (PAT) incentives are explored in this paper. The paper presents energy models to enhance knowledge and skills in the efficient transfer and management of technology for optimally allocating different types of renewable resources, technology and economic feasibility. [ABSTRACT FROM AUTHOR]

A sustainable energy system can be treated as a development of the distributed generation concept. It meets energy demands locally from renewable energy or/and high-efficiency polygeneration production technologies, and is characterized by energy and cost efficiency, reliability, and environmental-friendliness. Distributed energy systems typically use renewable energy resources to supply all energy demands, such as heat, cooling, and electric power in an integrated way. However, it seems that too much emphasis is placed on power and associated renewable energy-based power technologies for dealing with sustainability issues in public discussion and the research community. Often, equally important thermal energy (heat and cooling) and polygeneration are ignored. Polygeneration is an energy-efficient technology for generating simultaneously heat and power as well as other energy products in a single integrated process. Energy efficiency contributes significantly to CO 2 emission reduction. This paper discusses the role of polygeneration in a distributed energy system and the contributions of polygeneration to the development of sustainable energy systems. The paper also stresses that efficient decision support tools for sustainable polygeneration systems are important to achieve sustainability. First, the joint characteristic of a polygeneration plant that defines the dependency between different energy products is reviewed. Then, typical methods for dealing with polygeneration systems are reviewed. The review attempts to highlight the complexity of polygeneration systems and potential of polygeneration systems to adjust output of different energy products. Next, the challenges of sustainable polygeneration energy systems are discussed. Then some practices for operating polygeneration plants are discussed. [ABSTRACT FROM AUTHOR]

Job creation is an important component of the socio-economic effects associated with the development and deployment of renewable energy (RE) and energy efficiency (EE) technologies. The potential contribution of the RE and EE sectors in creating new jobs affect the public policy as well as the allocation of public resources to promote related activities. This paper provides an overview on the job creation potential along the value chains of key RE and EE technologies by skill set, technological category and the stage in the life cycle of the development and deployment process. We summarize the existing approaches to estimate job creation effects of the RE and EE sectors and report the existing estimations of job creation figures by technology and capacity. The paper concludes with the cases studies on Germany, Spain, the United States and the Middle Eastern region to showcase the variation of job creation potential in different regions. [ABSTRACT FROM AUTHOR]

Demographic change, dramatic population increase and rapid industrial growth are major trends emerging in Malaysia. Climate change and depletion of fossil fuel along with the rise in petroleum prices have forced the Malaysian Government to rethink strategies to be more in line with other developed countries including the decision to embark on renewable energy (RE) resources as a better source of energy amongst the global energy mix. The Malaysian Government is making frantic efforts to make policies, RE programmes and incentives more effective so as to promote and develop the use of RE. Malaysia is rich with fossil fuel but these are fast depleting. Although RE is necessary, current RE resources are still not enough. Therefore, exploration into other resources must be considered in order to meet future energy demands. The objective of this paper is to identify the potential of available renewable energy resources in Malaysia as well as the country׳s current implementation strategies. This paper also discusses the different RE policies in Malaysia. In order to determine the potential of RE, various sources and published materials in conferences, international journals and information released by relevant government bodies and miscellaneous resources are used. This research has revealed that among all the renewable energy sources that are present in Malaysia, biomass and solar energy are the most prospective ones. Plus, renewable energy (RE) sources are quite advantageous as they are free from greenhouse gas (GHG) emissions and related global warming effects. They can also be applied in off-grid electricity generation for rural communities. [ABSTRACT FROM AUTHOR]

By 2020 Europe has to increase its energy efficiency and share of renewables in 20%. However, even accomplishing these challenging objectives Europe will be effectively wasting energy as we demonstrate in this paper. In our way towards a fully renewable scenario, we need at least to stop wasting energy in order to guarantee the energy supply needed for growth and comfort. We waste energy when we employ more primary energy than the final energy we ultimately use and this excess cannot be reutilized. In this paper we propose the WE (wasted energy) as a novel metric to measure the performance of energy systems and set up appropriate targets. The WE incorporates information about energy efficiency and renewable sources. Unlike European legislation, the WE considers them in an integrated way. This approach will help Member States to exploit their intrinsic capabilities and design their optimum strategy to reach their objectives. Using the information in Eurostat, we calculate the WE of Member States in EU-28 and their evolution. We also analyze illustrative examples to highlight strategies to reduce the WE, study the connection between economic development and WE, and provide a tool to diagnose the potential of improvement of an energy system. [ABSTRACT FROM AUTHOR]

The increasing energy demand in harbour areas, coupled with the need to reduce pollutant emissions, has led to the development of renewable energy-based polygeneration systems to face the carbon footprint of ports and ships at berth. In this way, in the coming years, ports can be converted into modern energy hubs. From this point of view, this paper presents a new dynamic simulation model for assessing and optimizing the energy and economic impact of ports. Here, energy systems and renewable sources can be designed to be connected to national electricity and natural gas grids and can include also alternative fuels (hydrogen, biomethane, etc.) and thermal energy networks, as well as different biomass fluxes (to be exploited for energy aims). Energy availability/demands of near towns and port buildings/infrastructures, as well as on-shore power supply are also included in the dynamic assessments. Hourly weather data and different prices for all the considered energy carriers are taken into account hour by hour. A multi-objective optimization approach is also implemented in the model considering energy and economic indexes to be optimized. The whole model is implemented in a computer tool written in MATLAB. For showing the capability of the developed model, a novel case study referred to the port of Naples (South-Italy) is presented. Here, several renewable energy sources are considered, including an anaerobic biodigester for producing biogas from the organic waste of docked cruise ships. A combined heat and power system (fed by biogas) is implemented in the port energy hub also for supplying absorption chillers. PV panels, and marine power generators are also included. In the conducted analysis, optimization targets are the maximization of system self-consumption and self-sufficiency as well as the minimum simple payback period. The proposed system can effectively contribute to the decarbonization of the port energy demand and reduce harmful pollutant emissions. Results showed that very high rate of renewable energy produced on-site can be exploited (up to 84%) by the considered port facilities, ensuring increasing independency from utility power grid (self-sufficiency index up to 40%). By the obtained results and through the developed simulation/optimization tool, novel design and operating criteria can be achieved for future port energy hubs featured by renewables and bi-directional energy exchange between ships and port. [ABSTRACT FROM AUTHOR]

[Display omitted] • nZEBs in Eastern Europe lack carbon neutrality metrics and targets. • Performance requirements for nZEBs in Eastern Europe are presented. • Eastern Europe needs strategy and local governance for nZEB market penetration. • EPCs require major reform, and effective monitoring of nZEB performance is needed. • The cost-optimality calculation method must be adopted to ensure cost-effective market uptake. The European Unions' ambition for the construction sector is to be carbon neutral by 2030 for new construction. Since 2021, all new buildings in the EU should have been constructed as nearly zero-energy buildings (nZEB). However, Eastern European countries struggle to implement the 2018 Energy Performance of Building Directive recast requirements. Next to the economic challenges, equally essential factors hinder renovating the existing residential building stock and adding newly constructed high-performance buildings sourced primarily from renewable energy sources. Therefore, this study provides a cross-study to identify the barriers to nZEB implementation in ten Eastern European countries, including Bulgaria, Croatia, Czechia, Estonia, Hungary, Latvia, Lithuania, Poland, Romania, and Slovakia. The study was conducted between 2019 and 2021 and provides an overview of prospects for nZEB in Eastern Europe. The study examines the challenges of nZEB plans faced in those countries and provides constructive recommendations. The regulations and definitions regarding nZEB energy performance, cooling and heating energy demand, thermal comfort, onsite renewables, and construction quality were analyzed. Results show that most Eastern European countries are unprepared to comply with the EPBD guidelines and cost-optimality approach. The paper ranks each country and recommends specific measures to refine the nZEB definitions. The paper provides a thorough comparative assessment and benchmarking of select EU geography that can help shift the identified gaps into opportunities for the future development of climate-neutral high-performance buildings. [ABSTRACT FROM AUTHOR]

Cement manufacturing is an energy and carbon-intensive industry. The cement industry contributes approximately 5% of the global man-made carbon dioxide (CO 2 ) emissions and is thus becoming the second largest CO 2 contributor in industry after power plants. A wide range of options are available to considerably reduce CO 2 emissions. This paper reviewed major point sources of CO 2 emissions at all stages of cement manufacturing, including (1) raw material preparation (grinding and transportation), (2) clinker production and the combustion of fuels in the kiln and (3) the production of cement final product (milling, blending, mixing, packaging and transportation. Various CO 2 mitigation strategies are subsequently discussed, including (1) energy efficiency improvements; (2) waste heat recovery; (3) the substitution of fossil fuel with renewable energy; (4) the production of low carbon cement by replacing ordinary Portland cement with alternative materials, i.e., geo-polymers, blast furnace slag, coal fly ash, and natural pozzolanic materials; and (5) carbon capture and storage. Although reviewed CO 2 mitigation measures are indeed beneficial to the environment, however, they are also bounded by some limitations. The limitations and selection of CO 2 mitigation measure are also outlined in this paper. [ABSTRACT FROM AUTHOR]

This paper recognizes the synergetic relationship and inextricable linkage between conservation and sustainability. Heritage preservation maximizes the use of existing materials and infrastructure, reduces waste, and preserves the historic character of older towns and cities. This paper also presents technical advances in BPS/BES (Building Performance Simulation/Building Energy Simulation), and in co-simulation for energy efficiency optimization, RES integrated historic building's greening and historic neighborhoods, settlements, as well as whole cities urban re-planning. Further, the paper presents initial results of the Aviation Museum in Belgrade preliminary energy refurbishment study focusing results obtained via BPS and co-simulation. Foreseen is the deep energy refurbishment aimed to reach the “total building performance optimization” encompassing multifunctional optimization of building's skin – glazing replacement with the semi-transparent PV glazing and day-lighting control with reference to the artifact preservation, as well as the IEQ (Indoor Environment Quality) control analysis. This study shows that the RES integrated refurbishment can result in the Museum's Zero CO 2 emission and even in the sustainable Energy + status (producing more than using electricity). Finally, needs for most current ICT knowledge use and refurbishment technologies development, as well as integrated design, including particularly relevant benchmarking and rating system development are outlined. [ABSTRACT FROM AUTHOR]

In this paper, four energy control strategies are proposed and analyzed for the standalone Renewable/Fuel Cell Hybrid Power Source (RES/FC HPS). The concept of the load following (LF) and Maximum Efficiency Point Tracking (MEPT) is used to control the fueling rates. A standalone RES/FC HPS uses at least one Renewable Energy Sources (RES) and a Polymer Electrolyte Membrane (PEM) Fuel Cell (FC) as backup source. Photovoltaic (PV) array and wind turbines (WT) farm are used as RES and the surplus of energy during light load stages is stored in hydrogen tank via water electrolysis to fuel the PEMFC. Small-scale RESs and commercially available PEMFCs are interfaced to the common DC bus via power converters and then to the single-phase distribution grid through a voltage source inverter. RES/FC HPS seem to be an efficient alternative for supplying smart houses and isolated sites. This paper proposes a new supervision strategy of the Energy Management Unit (EMU) based on the LF control approach that assures a charge-sustaining (CS) mode for the Energy Storage System (ESS). So, the capacity of the batteries stack can be reduced at minimum if it is directly connected to the DC bus. The ultracapacitors stack compensates dynamically the power flow balance on the DC bus, regulating the DC voltage via a bidirectional buck-boost power converter. Thus, a semi-active hybrid topology is adopted for the ESS having the batteries stack. The MEPT loops ensure an optimized energy management of the RES/FC HPS. The LF strategy designed based on the power flow balance guarantees the load demand through the efficient management of the power flow from RES, FC and ESS, adapting FC energy production to load profile. The FC energy production is controlled via the fueling rates (one is controlled in the LF loop and the other is controlled in the MEPT loop) to maximize the energy consumption indicator: the ratio of the produced energy and the fuel consumed by the FC system during a load cycle. Thus, this paper evaluates the control performances of the four control topologies to fuel the FC stack during an variable RES and load profile. The MATLAB-Simulink® software package is used to model the RES/FC HPS and develop the four EMU strategies. Simulation results shown comparatively the performance of the EMU strategies proposed under different scenarios of RES power generation and load demand. [ABSTRACT FROM AUTHOR]

A detailed assessment analysis of 2.5 kWp photovoltaic (PV) system located in southern Algeria (Latitude 27.88 °N, Longitude −0.27 °E, Altitude 262 m) has been carried out in this paper in order to support the growth of grid-tied photovoltaic power plant implementation in the Saharan environment. The achievement of this analysis has been done by performing an accurate evaluation of the different impacts of the environment parameters on the operating performance of the grid-tied PV system. The data set covers 12 operating months and has been collected by our team from the Research Unit on Renewable Energy (URER-MS). The collected experimental data reveal that the environmental parameters variation has direct effect on the performance of both energy conversion efficiency and system losses. The grid was supplied with a power of 4322.65 kWh during the year 2015, where the annual average temperature was 28.30 °C. An important variation in performance parameters have been observed for different months. The yield values of max/min monthly average daily reference, array and final were; 7.68/5.7 kW h/kWp/day, 6.07/4.24 kW h/kWp/day and 5.75/3.98 kW h/kWp/day, respectively. The PV module, inverter and overall system efficiency reached; 14.19/11.10%, 95.34/93.94% and 13.53/10.50%, respectively. The experimental results indicate that the performance ratio (PR) varies from 66.66% to 85.93% and the annual average capacity factor was 7.91%. [ABSTRACT FROM AUTHOR]

This paper integrates solar energy, regarded as the most abundant renewable energy in the world, into oil and gas industries to produce the hydrogen required in crude oil upgrader processes. Three alternatives of producing hydrogen from solar energy were proposed, namely, Solar Steam Methane Reforming using a Volumetric Receiver Reactor (SSMR-VRR), Solar Steam Methane Reforming using Molten Salt (SSMR-MS), and Solar Thermal Power generation coupled with Water Electrolysis (STP-WE). Simulations of all alternatives have been done to produce 2577 kmol per hour hydrogen: that is, the demand in the crude oil upgrader process. The technical, economic, and environmental analysis is performed to compare the results of the alternatives with the conventional steam reforming of natural gas. The results suggest that SSMR-VRR has the lowest levelized cost of hydrogen production, which is $2.5 per kg of hydrogen; SSMR-MS has a highest energy efficiency of 68%, and STP-WE has the lowest greenhouse gas emissions. The economic analysis suggests that currently the thermochemical processes (SSMR-VRR and SSMR-MS) have potential for producing hydrogen required by the crude oil upgrader; however, as the renewable energy technologies progress that may lead to their capital cost decrease, solar thermal power with water electrolysis (STP-WE) will become a more promising sustainable option for hydrogen production. [ABSTRACT FROM AUTHOR]

This work shows a technical review for two promising technologies and two commercial systems that can be applied in Hybrid Wind Systems —also known as Extraction Water from Air Systems (EWAS) — for the special weather conditions presents in Brazilian northeast. Additionally, a full description of the main components for the innovative technologies and for commercial solutions are explained. An energy consumption analysis for each one of these systems is made for comparison purposes. Water extraction capacity and energy efficiency are evaluated (for two commercial EWAS) for a theoretical operation point in the middle of the North–eastern semi–desert region. This point is obtained by means of the well–known humid air diagram. Important information about minimum environmental conditions for Membranes and Coils are also considered. Three main types of electric generators are described, including its advantages and disadvantages, for the estimation of the power ratio to generating electricity and water. For all above, the right sizing of the future Brazilian EWAS prototype and its possible application in a semi-arid region is the objective of this paper. [ABSTRACT FROM AUTHOR]

The creation of a sustainable built environment is related not only to energy-efficient construction but also to the efficient use of materials, in order to minimise environmental impacts and avoid further depletion of natural resources. However, “passive” or “zero-energy” buildings, which optimise operational energy, require additional materials (e.g. insulation) or the installation of technologies (e.g. mechanical ventilation) which further increase the embodied energy of the building and related environmental emissions. This paper questions the environmental impact and benefits of adding materials and technologies in order to reduce the energy consumption of a building by evaluating the embodied and operational energy of a case study of a passive housing block in Austria. The analysis is carried out using real data, based on energy monitoring carried out over three years, and on original documentation of the materials and construction of the building. Applying a Life Cycle Assessment (LCA) method, the environmental impacts of the building materials, the heating, ventilation and air-conditioning (HVAC) technologies, and the operational energy were assessed and compared for time scenarios of 20, 50 and 80 years using the environmental indicators: Global Warming Potential (GWP); Primary Energy Intensity (PEI); and Acidification Potential (AP). Two different variants of the “as built” building were modelled and investigated in terms of their ecological impacts. It was found that distribution pipes for building services apparently contributes 10% of the GWP, and the optimisation using timber instead of concrete is advantageous in terms of minimising GWP and AP, but is less effective in terms of PEI. Finally, the apartment block “as built” to a passive house standard was compared with a low-energy equivalent building in order to question whether the increased input of materials for the passive house is justified in terms of the reduction of the energy demand during the operation of the building. It was found that the passive house performs better in terms of environmental impacts, but not significantly so (max. GWP saving of 7% in the 80 years scenario). The reasons are multifaceted, and include additional heating of the apartments by the occupants, uncontrolled window opening patterns and increased hours of occupancy. [ABSTRACT FROM AUTHOR]

In a low-carbon and sustainable future, smart grids have a key role to play not only in saving energy with demand and supply-side management of energy systems, but also in optimizing the integration of a wider range of generation and storage options including renewable energy sources. Moreover, some challenges can follow the transition from a traditional grid into a smart grid. In this context, “public attitude” and “public acceptance” are major components to make more radical scenarios about the feasible implementation of smart grid technologies and successful integration of renewable energy sources. This paper presents unique survey results of public attitudes towards smart grids, smart meters, renewable energy and environment in Qatar using a representative panel from Qatar University community. It contributes to the literature by providing a better understanding of electricity consumers’ perception and behavior about the possible deployment of smart grid applications. It also aims to create data about public attitudes to inform policy makers, the business community and other stakeholders for decision-making by introducing institutional and regulatory changes, and modifying the relationship between consumers, the government and utilities. The main conclusions can be used as a basis for sustainable energy planning, and awareness campaigns formulation in order to enhance public acceptance regarding renewable energy projects and smart grid technologies. However, the results are a first attempt to elicit public views and will need to be extended to the larger community in Qatar and repeated at regular basis. [ABSTRACT FROM AUTHOR]

This paper presents the methodological approach and findings of a simulation study of advanced energy conservation, generation and management technologies applied to two case study dwellings in the UK, so as to achieve net zero energy (NZE) target that includes a reduction of net regulated energy (HVAC) to 0 kWh/m 2 per year and energy generation of at least 50 kWh/m 2 per year. The performance of the dwellings are also tested for a change in energy use and risk of summertime overheating in future climates in the short (2030s), medium (2050s) and long term (2080s). The findings indicate that to meet the NZE targets, regulated loads need to reduce by about half (over current Building Regulations) with community (rather than building-level) renewables playing a major role. It is also found that the NZE targets, given current regulations, are not particularly difficult to achieve in design with regard to energy efficiency but are highly expectant with regard to renewable energy. Further, summertime overheating is projected to be a risk for net zero energy dwellings by the 2050s. Despite this the regulated energy use of both dwellings is projected to reduce by 11 kWh/m 2 /yr, accompanied by a small increase in renewable generation (2 kWh/m 2 /yr). [ABSTRACT FROM AUTHOR]

This paper proposes a novel Case Based Reasoning (CBR) application for intelligent management of energy resources in residential buildings. The proposed CBR approach enables analyzing the history of previous cases of energy reduction in buildings, and using them to provide a suggestion on the ideal level of energy reduction that should be applied in the consumption of houses. The innovations of the proposed CBR model are the application of the k -Nearest Neighbors algorithm (k-NN) clustering algorithm to identify similar past cases, the adaptation of Particle Swarm Optimization (PSO) meta-heuristic optimization method to optimize the choice of the variables that characterize each case, and the development of expert systems to adapt and refine the final solution. A case study is presented, which considers a knowledge base containing a set of scenarios obtained from the consumption of a residential building. In order to provide a response for a new case, the proposed CBR application selects the most similar cases and elaborates a response, which is provided to the SCADA House Intelligent Management (SHIM) system as input data. SHIM uses this specification to determine the loads that should be reduced in order to fulfill the reduction suggested by the CBR approach. Results show that the proposed approach is capable of suggesting the most adequate levels of reduction for the considered house, without compromising the comfort of the users. [ABSTRACT FROM AUTHOR]