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In recent years, harvesting solar energy as a renewable and sustainable energy source has been studied extensively across engineering fields. Having reviewed more than 50 large-scale projects of Hydronic Asphalt Pavement (HAP), this paper offers a series of findings: the range of construction cost of asphalt collector varies between 25 and 151 €/m2 and 1.760–3.000 €/m2 for the heat exchanger and the total cost. The energy harvest capacity of asphalt solar collector systems (0,6–0,8 GJ/m2/year) and the required amount of heat for snow melting projects (100–900 W/m2) vary significantly in different projects. Using grid supports for easier pipe placement and protection of pipes against heavy loads during and after construction is recommended. Pavement solar collector systems reduced carbon dioxide emissions by 8–100% in different projects by changing their source of energy from fossil fuels to renewable and sustainable sources. Moreover, in order to further evaluate the sustainability of the HAP systems, a detailed life cycle assessment is required, including all available data related to the energy performance, pavement service life, material end-of-life recycling, etc. Finally, the paper identifies the knowledge gaps requiring further research especially in the area of energy output of the HAP systems, pavement service life and life cycle assessment. • A comprehensive review of large-scale hydronic asphalt pavement projects is provided. • Potential challenges in the large-scale hydronic asphalt pavement are investigated. • Technical specifications, operational aspects and performance are explored. • Construction cost and structural response of systems are analyzed. • The projects' performance is evaluated based on energy output and sustainability. [ABSTRACT FROM AUTHOR]

Systems involving more than one energy source, namely hybrid systems, can be arranged in different configurations and layouts depending on the available or used energy source, application and scale of the system. Despite an increasing awareness and penetration of renewable energy sources at different scales in many countries over the world, the adoption of hybrid and novel renewable systems is relatively scarce, especially at a small scale. This scenario is also presented from the point of view of the research of such systems. Therefore, the scope of the paper is to improve the knowledge regarding small-scale hybrid renewable energy systems performance and operation by investigating a novel trigeneration system based on a biomass fired steam cycle, wind turbine, photovoltaic panels and adsorption chiller. In the proposed system, the thermal energy recovered by the steam cycle is used to match the user thermal demand by means of a storage tank supplying directly heat to the user during winter, and driving the adsorption unit during summer. The electrical energy produced by the steam turbine, photovoltaic field and wind turbine is managed by a control system that integrates a bidirectional connection with the electric grid. The grid allows one to virtually store the electrical energy produced in excess and to recover it in part when needed by the user. In order to assess the system performance, a farm and residential buildings are considered as case study. The proposed system is modelled and dynamically simulated by means of Transient System Simulation software. In the paper, the dynamic operation of the system and the energy and economic performance of the system is assessed. The operation of the system is presented in a daily and monthly basis, while the global performance parameters of the system are reported considering a one-year period. The primary energy saving of the system is above 70% when a reference system based on natural gas, electric chiller and grid is considered. For this scenario, the Simple Pay Back of about 10 years is achieved. The results of the analysis show that the system is feasible from the technical and energy point of view, whereas its economic profitability is significantly affected by its cost and the reference system that is adopted by the user. • Modeling and dynamic simulation was performed with TRNSYS software. • Energy and economic performance of the system was assessed. • Different reference systems are considered for heating. • Primary Energy Saving ratio was between 57.4 and 73.3%. • The minimum Simple Pay Back is about 10 years. [ABSTRACT FROM AUTHOR]

Recently, renewable energy generation (REG) forecasting has become a challenging task for effective energy management. To date, a number of time-series models utilizing physical models, statistical techniques, and artificial intelligence algorithms have been proposed to deal with this problem. Fuzzy time series (FTS) models stand out among these methods since they do not need extensive historical data or some statistical assumptions like the normal distribution. Because intuitionistic fuzzy sets incorporate non-membership values in addition to membership values, they provide more information than conventional fuzzy sets do. In this regard, this paper recommends a hybrid methodology that combines the intuitionistic FTS method with the intuitionistic fuzzy c-means method for REG forecasting of Turkey between the years 2000–2020. According to the empirical results, it can be concluded that the presented integrated model showed good performance in terms of accuracy. The suggested framework is a useful tool not only for REG forecasting but also for other time series forecasting problems. [ABSTRACT FROM AUTHOR]

Power-to-ammonia (P2A) technology has attracted more and more attention since ammonia is recognized as a natural zero-carbon fuel. In this context, this paper constructs a renewable energy powered multi-energy hub (MEH) system which integrates with a thermo-electrochemical effect based P2A facility. Subsequently, the energy management of proposed MEH system is casted to a multi-agent coordinated optimization problem, which aims to minimize operating cost and carbon dioxide emissions while satisfying constraints. Then, a novel multi-agent deep reinforcement learning method called CommNet is applied to solve this problem to obtain the optimal coordinated energy management strategy of each energy hub by achieving the distributed computation of global information. Finally, the simulation results show that the proposed method can achieve better performance on reducing operating cost and carbon emissions than other benchmark methods. [ABSTRACT FROM AUTHOR]

To improve the renewable energy sources (RES) utilization of isolated microgrids (IMG) in frequency regulation process, an adaptive frequency regulation strategy with high renewable energy participating level is proposed in this paper: 1) an adaptive droop control method is conceived for primary frequency regulation, in which the designed droop coefficients are adjustable with the real-time wind velocity and state of charge (SoC) of energy storage units (ESUs); as the most important contribution, 2) a general flexible model predictive control (FMPC) framework with adaptive cost function and constraints is developed for secondary frequency regulation. For 2), i) the weight coefficients of the cost function can be adaptively adjusted according to frequency deviation through a pre-designed intelligent function, in which the specification of determining the key parameters is involved; ii) the designed constraints' boundaries can dynamically shift with wind velocity and ESU's SoC; iii) the negative impact of model's uncertainties can also be mitigated by implementing the proposed FMPC. Finally, the effectiveness of the proposal is verified by the comprehensive simulation and experimental study, and the results show that the proposal can significantly improve RES's utilization level while guaranteeing frequency regulation performance and operation safety in IMG. [ABSTRACT FROM AUTHOR]

As the solar energy utilization technology for renewable clean energy, actual parabolic trough receivers are subject to tracking errors and absorber tube installation errors, and the bellows and Kovar ring under these errors have a significant impact on the receiver's safety. Based on the MCRT-FVM-FEM principles in this paper, a receiver's optical-thermal-stress mathematical model is modeled and the thermal-stress performance and safety of the receiver's key components under two errors are evaluated. The correlation between the bellows and Kovar ring's performance and the two errors is analyzed. The results demonstrate that the lower tracking errors and larger installation errors markedly increment the absorber's deformation and have a negative impact on the receiver safety. Bellows and Kovar ring's asymmetrical temperature distribution causes variable swell and uneven stress under tracking and installation errors. Temperature gradient variation of bellows is more sensitive under errors than Kovar rings. Kovar ring's compressive stress rises substantially as the Y-directional installation error varied from −15 mm to 15 mm compared to other errors. With tracking errors exceeding 8 mrad, bellows' tensile stress and Kovar ring's compressive stress diminish under installation error. Thus, larger tracking errors significantly reduce the threat to the receiver when installation errors exist. [ABSTRACT FROM AUTHOR]

With the high penetration of renewable energy, its intermittency and volatility also bring challenges to traditional power system such as maintaining reliable operation of system and improving the utilization of renewable energy. Under the background of Energy Internet (EI), energy router (ER) emerges as the times require. Aiming to improve the ability of support of energy storage units to DC buses and suppressing power shocks both inside and outside the ER, in this paper, an ER based on multi-hybrid energy storage system (MHESS) is proposed. As the principle of maximizing the utilization of renewable energy, a corresponding energy coordinated management strategy is proposed. Charging/discharging timespan optimization model is established to ensure MHESS as available as possible. The reference power of MHESS is allocated based on the proposed optimization model. Simulation analysis of different working conditions in 4 operation scenarios are carried out and the results show that the power oscillation on different buses of ER can be dampened within 0.1s and the bus voltages fluctuate within 2% while operation scenarios are switched, which verifies the feasibility and effectiveness of the proposed energy coordinated management strategy. [ABSTRACT FROM AUTHOR]

Over the last two decades, there has been a significant interest in developing solutions to improve the efficiency of power systems, such as optimal energy consumption and management. The demand response programs (DRP) have long been one of the most effective strategies to encourage consumers to change their consumption behavior. In this paper, a novel hybrid DRP has been implemented by combining the time of use (TOU) and incentive-based (IB) DRP methods. To meet the load demand, a PV-WT-BESS hybrid renewable energy system (HRES) has been proposed in this work. Further, to analyze the impact of hybrid DRP on the capacity allocation of different system components, optimal sizing has been performed in two scenarios, one with the actual load and the second with the load after considering the hybrid DRP. The optimization has been carried out by using an improved search space reduction (ISSR) algorithm. To demonstrate the effectiveness of the ISSR algorithm, the obtained results are compared with other algorithms such as particle swarm optimization (PSO), grey wolf optimization (GWO), teaching-learning based algorithm (TLBO), seagull optimization algorithm (SOA), and sine cosine algorithm (SCA). Finally, a novel energy management strategy (EMS) is also proposed in this work on the supply side of the HRES, which intelligently uses the variations in the grid tariff to charge the BESS when the tariff is low. To demonstrate the proposed DRP and EMS-based sizing, a case study has been performed for a grid-connected PV-WT-BESS for the location of Kanyakumari, India. From the results obtained, it has been concluded that the hybrid DRP reduces the peak demand up to 5%, which reduces the levelized cost of energy (LCE) by 22%. Furthermore, the proposed novel EMS reduces the LCE further by 5%. The overall cost reduction of up to 25% has been achieved by using both the proposed hybrid DRP and EMS, while satisfying all necessary constraints. [Display omitted] [ABSTRACT FROM AUTHOR]

Distributed energy systems are becoming increasingly popular worldwide. The 100% renewable energy system can be an important energy supply alternative to reduce the carbon emissions and address energy shortage, especially for remote areas. However, the performance of 100% renewable energy system (RES) at community level needs further detailed analysis, which is affected by the climates, availability of renewable energy and local energy markets. This paper proposes a design optimization framework of 100% renewable energy systems for low-density communities and investigates the system performance. To investigate the integration and performance of 100% RES, thirty typical cities located in different regions of China were chosen considering different climates, geographical features, and renewable energy distributions. By taking the economic performance as the optimization objective, the optimal design for the 100% RES is obtained, and the energy and economic performance is analyzed. Results show that, under the current energy market conditions, the 100% RES is feasible for low-density communities in most regions of China. The payback periods of the systems in most cities are less than six years. When the cost of PV is reduced by half considering future technological developments, the payback period of a 100% RES can be reduced by 30%–60%. This paper would provide design suggestions and application recommendations in regard to promoting 100% RES in China. • Application of 100% renewable energy system at community level is studied. • 30 zones are selected considering climates, renewable energy sources and markets. • Solar energy and biomass can contribute to over 90% of the total energy supply. • Investment of 100% RES can be paid back in 6 years for most regions. • Payback periods can be reduced by 30%–60% when PV technology is further developed. [ABSTRACT FROM AUTHOR]

The present study of the district heating (DH) system in the city of Kisa, Sweden, shows how, through energy cooperation with a nearby sawmill and paper mill, a local energy company contributes to energy-efficient DH and cost-effective utilization of a new biofuel combined heat and power (CHP) plant. Cases of stand-alone and integrated energy systems are optimized with the linear program MODEST. The European power market is assumed to be fully deregulated. The results show clear advantages for the energy company to cooperate with these industries to produce heat for DH and process steam for industry. The cooperating industries gain advantages from heat and/or biofuel by-product supply as well. The opening to use a biofuel CHP plant for combined heat supply results in cogenerated electricity of almost 29 GWh/a with an increased biofuel use of 13 GWh/a, zero fuel oil use and CO 2 emission reductions of 25,800 tons CO 2 /a with coal-condensing power plant on the margin and biofuel as limited resource. The total system cost decreases by −2.18 MEUR/a through extended cooperation and renewable electricity sales. The sensitivity analysis shows that the profitability of investing in a biofuel CHP plant increases with higher electricity and electricity certificate prices. [ABSTRACT FROM AUTHOR]

The paper proposes an innovative power-sharing model, i.e., a power-system architecture for aggregation of users able to share the power produced by common generators and energy services. The model is suitable for both multi-tenant buildings and groups of multiple buildings and it is applicable for both existing and new buildings. It is scalable for larger systems and suitable for an easier integration with storage systems. The novel principle of the model is that the energy produced by common generators can be shared among the end-users in a unidirectional way, so that each user remains passive towards the distributor, except a single active user that assumes the role of balance node. This key feature allows for easily implementing the model in all the residential and tertiary multi-units buildings in full compliance with national regulations, with the adoption of power sharing contracts as well. This paper discusses the feasibility of the model through a dynamic Matlab/Simulink model, which is used to show its effectiveness in several case studies. The significance of this work consists of approaching the energy sharing in buildings with a completely new strategy, based on an innovative system architecture that can be effectively implemented. • Innovative democratic power-sharing model for building and energy communities. • It allows for aggregation of users. • It allows to share the power produced by common generators. • Each user remains passive towards the distributor. • The model can be implemented in all multi-units buildings. [ABSTRACT FROM AUTHOR]

Tremendous development and integration of intermittent renewable energy resources have forced the hydraulic turbines to experience transient processes more frequently and thus endangered the stability of the machine. The principal objective of this paper is to present the numerical investigation into load rejection towards a high-head model Francis turbine based on the structured overset mesh, which provides greater flexibility over the standard mesh techniques and adequate mesh quality during the movement of the guide vanes. The numerical results show good agreement with experimental measurements. The formation and evolution process of the vortex rope in the draft tube are elaborated by the velocity invariant Q and the swirl number S reaching its maximum value due to the formation of precessing vortex rope. Evidence is presented which shows that significant influence of the rotor-stator interaction is captured, and the pressure fluctuation amplitudes caused by the changing of angular position of guide vane are also powerful. Furthermore, the velocity profiles in axial and radial imply that an increasing recirculating flow region is developed at the center of the draft tube during the transient process. The findings presented in this paper enhance the insight into transient features of load rejection process. - Load rejection process was simulated through the structured overset mesh technology. - Dynamic characteristics during load rejection was analyzed. - Formation of processing vortex rope was presented. [ABSTRACT FROM AUTHOR]

At present, energy represents a key element in the social and economic development of a territory. This is particularly true for fragile territories that are not interconnected, such as small island states. As is true for many of the Small Island Developing States (SIDS) worldwide, the energy situation of the Comoros is substantially based on fossil fuel imports. The socioeconomic development of this archipelago is overwhelmingly dependent on energy security from sustainability, availability and affordability perspectives. As a forward-looking response to energy vulnerability, the deployment of renewables to diversify the generation of electricity appears to be an essential prerequisite for guaranteeing a sustainable future. Nevertheless, despite a high potential for renewable energy, only 3.8% of the electricity supply in the Comoros is provided by hydropower. This paper provides a comprehensive overview of the energy situation throughout the Comoros and focuses on renewable energy opportunities to facilitate the supply of green power. This study ultimately shows that renewable energies are rarely exploited despite the powerful potential of different resources. Finally, this paper attempts to provide recommendations for the Comoros to pursue a more sustainable future. • Analysis of the current energy situation of Comoros. • Defining renewable potential and ongoing actions. • Analysis of the specific barriers and policy to the development of RES in the Comoros. [ABSTRACT FROM AUTHOR]

Integrating biomass, photovoltaic, and other renewable energy sources for hydrogen production can form a biomass-photovoltaic-hydrogen integrated energy system (BPH-IES). The system features multi-energy storage and joint supply, as well as cascaded utilization, is a promising co-generation way to meet the system's electricity, heat and hydrogen needs, and has significant energy-exergy-economy-environment (4E) performance. Therefore, scientific and effective evaluation of the BPH-IES is an important prerequisite for promoting its development. Firstly, by analyzing the structure of the BPH-IES system, this paper constructs a comprehensive performance evaluation index system of the system from the 4E dimensions. Secondly, a hybrid multi-criterion decision making (MCDM) framework for the 4E comprehensive performance evaluation of the BPH-IES is constructed, in which the anti-entropy weighting method is used to determine the objective weights, the subjective weights are determined by the decision making trial and evaluation laboratory method improved by intuitionistic fuzzy sets, and the final combined weighting results are obtained based on a game-theoretic method that the objective and subjective weights' heterogeneity can be fully minimized. The grey-relation-analysis-based measurement alternatives and ranking according to the compromise solution method is proposed to determine the ranking of alternatives. This paper selected 8 typical BPH-IES cases for 4E evaluation analysis. The results showed that energy performance is the core dimension that reflects the 4E performance of the system, and system's economy indicators such as energy supply income and energy supply cost will also significantly affect the system's 4E performance. Therefore, the 4E performance of BPH-IES can be effectively improved by expanding the system's demand and supply scale and increasing the system's installed proportion of clean energy and hydrogen penetration. Finally, the ranking consistency test, Leave-One-Out analysis and sample separation test demonstrate that the developed hybrid MCDM can ensure robustness meanwhile improve the decision efficiency. [ABSTRACT FROM AUTHOR]

In recent years, the government has attached great importance to promoting innovation in new energy technologies, particularly in the area of solar power generation. Photovoltaic (PV) power generation has become an essential factor in the promotion of renewable energy due to its inherent safety, environmental sustainability and abundant solar energy resources. The efficiency and stability of PV generation systems are closely related to the accurate prediction of real-time global horizontal irradiance (GHI). However, some existing research methods have made some progress in hourly resolution, but the multi-step prediction accuracy and model generalization ability in high time resolution are still unsatisfactory. Therefore, this paper proposes a novel minutely multi-step irradiance forecasting based on all-sky images using LSTM-InformerStack hybrid model with dual feature enhancement scheme. In this scheme, the advantages of both LSTM and InformerStack models are combined to further enhance the global and local features, which can better capture the short-term time series patterns and long-term dependencies and improve the accuracy of the time series. The experimental validation results show that the performance of this prediction scheme is improved by 11.2%, and 26.0% for nRMSE and R2, respectively, and the 24-step prediction can be improved up to 26.1% vs. the persistent model. Meanwhile, the prediction scheme of this paper is also expected to provide a reference in future multi-step time series accurate prediction with higher resolution. [ABSTRACT FROM AUTHOR]

In the pursuit of sustainable energy solutions, the integration of renewable energy sources and hydrogen technologies has emerged as a promising avenue. This paper introduces the Integrated Renewable Energy-Driven Hydrogen System as a holistic approach to achieve energy independence and self-sufficiency. Seamlessly integrating renewable energy sources, hydrogen production, storage, and utilization, this system enables diverse applications across various sectors. By harnessing solar and/or wind energy, the Integrated Renewable Energy-Driven Hydrogen System optimizes energy generation, distribution, and storage. Employing a systematic methodology, the paper thoroughly examines the advantages of this integrated system over other alternatives, emphasizing its zero greenhouse gas emissions, versatility, energy resilience, and potential for large-scale hydrogen production. Thus, the proposed system sets our study apart, offering a distinct and efficient alternative compared to conventional approaches. Recent advancements and challenges in hydrogen energy are also discussed, highlighting increasing public awareness and technological progress. Findings reveal a payback period ranging from 2.8 to 6.7 years, depending on the renewable energy configuration, emphasizing the economic attractiveness and potential return on investment. This research significantly contributes to the ongoing discourse on renewable energy integration and underscores the viability of the Integrated Renewable Energy-Driven Hydrogen System as a transformative solution for achieving energy independence. The employed model is innovative and transferable to other contexts. [Display omitted] • Integrating renewable energy and hydrogen for energy independence. • Advantages of Integrated Renewable Energy-Driven Hydrogen System: Zero emissions, resilient energy. • Economic viability: Payback period of 2.8–6.7 years. • Technological progress in hydrogen energy. • A novel and transferable system dynamics model for sustainable solutions is proposed. [ABSTRACT FROM AUTHOR]

The increasing demand for renewable energy sources has led to the development of HRES that combine multiple sources of renewable energy to provide a reliable and efficient energy supply. However, renewable energy sources typically come with higher costs than conventional energy production methods. Hence, the optimal sizing of HRES is essential to prevent the oversizing of the system while ensuring a reliable supply of load demand, accommodating variations in meteorological conditions and changes in power demand. Numerous research papers addressing the optimal sizing problem are available in the literature. However, none of the mentioned studies take into account the power degradation of all renewable sources. The degradation of renewable sources, such as PV and WT, can have a significant impact on the performance of HRES. The degradation of PV panels can result in reduced efficiency and output, leading to a decrease in the overall energy production of the HRES. Similarly, WT may experience wear and tear over time, leading to reduced performance and output. The reduction in the output of renewables in the standalone system causes an increase in the loss of power supply probability (LPSP). This paper analyzes the optimal sizing of the HRES, considering the degradation of the sources. Further, analysis has also been carried out based on the number of BESS to be added to HRES to meet the derived constraints and their impact on the cost of energy as well. [Display omitted] [ABSTRACT FROM AUTHOR]

In the pursuit of sustainable energy solutions, the integration of renewable energy sources and hydrogen technologies has emerged as a promising avenue. This paper introduces the Integrated Renewable Energy-Driven Hydrogen System as a holistic approach to achieve energy independence and self-sufficiency. Seamlessly integrating renewable energy sources, hydrogen production, storage, and utilization, this system enables diverse applications across various sectors. By harnessing solar and/or wind energy, the Integrated Renewable Energy-Driven Hydrogen System optimizes energy generation, distribution, and storage. Employing a systematic methodology, the paper thoroughly examines the advantages of this integrated system over other alternatives, emphasizing its zero greenhouse gas emissions, versatility, energy resilience, and potential for large-scale hydrogen production. Thus, the proposed system sets our study apart, offering a distinct and efficient alternative compared to conventional approaches. Recent advancements and challenges in hydrogen energy are also discussed, highlighting increasing public awareness and technological progress. Findings reveal a payback period ranging from 2.8 to 6.7 years, depending on the renewable energy configuration, emphasizing the economic attractiveness and potential return on investment. This research significantly contributes to the ongoing discourse on renewable energy integration and underscores the viability of the Integrated Renewable Energy-Driven Hydrogen System as a transformative solution for achieving energy independence. The employed model is innovative and transferable to other contexts. [Display omitted] • Integrating renewable energy and hydrogen for energy independence. • Advantages of Integrated Renewable Energy-Driven Hydrogen System: Zero emissions, resilient energy. • Economic viability: Payback period of 2.8–6.7 years. • Technological progress in hydrogen energy. • A novel and transferable system dynamics model for sustainable solutions is proposed. [ABSTRACT FROM AUTHOR]

The increasing demand for renewable energy sources has led to the development of HRES that combine multiple sources of renewable energy to provide a reliable and efficient energy supply. However, renewable energy sources typically come with higher costs than conventional energy production methods. Hence, the optimal sizing of HRES is essential to prevent the oversizing of the system while ensuring a reliable supply of load demand, accommodating variations in meteorological conditions and changes in power demand. Numerous research papers addressing the optimal sizing problem are available in the literature. However, none of the mentioned studies take into account the power degradation of all renewable sources. The degradation of renewable sources, such as PV and WT, can have a significant impact on the performance of HRES. The degradation of PV panels can result in reduced efficiency and output, leading to a decrease in the overall energy production of the HRES. Similarly, WT may experience wear and tear over time, leading to reduced performance and output. The reduction in the output of renewables in the standalone system causes an increase in the loss of power supply probability (LPSP). This paper analyzes the optimal sizing of the HRES, considering the degradation of the sources. Further, analysis has also been carried out based on the number of BESS to be added to HRES to meet the derived constraints and their impact on the cost of energy as well. [Display omitted] [ABSTRACT FROM AUTHOR]

Using daily data from the beginning of 2018 to the end of 2022 and the Seemingly Unrelated Regression method, this paper sought to determine the relationship between green and non-green cryptocurrency indices as representative of blockchain technologies on three green bond indices in two periods before the outbreak of COVID-19 and the corona period. The preliminary results confirmed that by spreading the coronavirus, the sensitivity of the green bond market has increased to the gold index. In addition, the green cryptocurrency index (Cardano) significantly impacts green bonds more during the Corona era. The negative effect of the Bitcoin index on the index of green bonds in the Corona era is less than its adverse effect in the pre-corona period. Developing green cryptocurrencies and linking cryptocurrencies and digital green financing are two significant recommended policy implications for scholars and policymakers. • Green cryptocurrency has a greater impact on green bonds during the Corona era. • During coronavirus, the sensitivity of the green bond to gold price has increased. • Bitcoin has negative impact on green bond indices before the COVID-19. [ABSTRACT FROM AUTHOR]

This paper investigates the potential of 15 RCEP (The Regional Comprehensive Economic Partnership) member countries to advance green investments from 2000 to 2021. Based on the results from the Panel Pooled Mean Group (PMG) technique, the investment potential has positive short- and long-term coefficients. The EKC (Environmental Kuznets Curve) hypothesis exists, indicating that gross domestic product per capita in the short term is the factor that inhibits the growth of renewable energy consumption. The financial development index has a non-significant coefficient in the short term. However, it has a positive coefficient in the long term. The climate policy uncertainty negatively impacts renewable energy deployment in the short- and long-term. The conclusions provide some policy implications, such as the support of green SMEs, the establishment of a digital green financing market, and the creation of green multilateralism through the establishment of a green investment network. • Environmental Kuznets Curve hypothesis exists in RCEP economies. • Financial development index has a positive and significant effect coefficient. • The climate policy uncertainty negatively impacts renewable energy deployment. [ABSTRACT FROM AUTHOR]

It is becoming increasingly important for human societies to use renewable energy. More effective energy storage solutions are crucial to increase the share of renewable energy in the domestic and industrial sectors, which consumes a large amount of thermal energy for heating and cooling purposes. There has been little quantitative analysis of thermal energy storage in solar-based cold production units. An efficient method of designing heat and/or cold storage systems and smart operation planning can help a cooling/heating system to be smaller for the same capacity of supply and thereby reducing the costs of initial investment and costs of operation. This paper attempts to show how the size of a heat and cold storage system affects its thermal performance and how it can lower costs and emissions. For this, a solar-assisted thermally driven cooling supply system with various designs and integrations of their cold storage unit is simulated dynamically through a whole year in Qassim region as the case study. The results show that a system design with double solar heat storage and double cold storage in parallel arrangement results in the best techno-economic-environmental performance. For this case, the levelized cost of cooling will be 383 USD/MWhr, which will be at least 3% lower than the typical hot/cold buffer tank design scenario. [ABSTRACT FROM AUTHOR]

Hydropower plants play an integral role in energy supply and are one of the main renewable energy sources. The efficiency of hydropower reservoir systems is controlled by operating rules that need to be optimized to maximize energy production. Here, a novel optimization algorithm, influential flower pollination algorithm (IFPA), is developed in this paper. IFPA has three enhancements: an efficient exploration mechanism based on an adaptive coefficient, a new exploitation mechanism around the best solution, and a rank-based strategy to smoothly transition from exploration to exploitation. IFPA is tested in two benchmark multi-reservoir systems and a real-world five-reservoir hydropower system in Iran. The results show IFPA outperforms other advanced methods in terms of convergence speed and preciseness to achieve the global solution. The tested algorithms include adaptive guided differential evolution (AGDE), composite DE (CODE), hybridizing sum-local search optimizer (HSLSO), improved teaching learning-based optimization (ITLBO), self-adapting control parameters in DE (jDE), self-adaptive TLBO (SATLBO), and a multi-strategy hybrid of DE and particle swarm optimization (MS-DEPSO). IFPA also achieved better total power production in the real-world case study compared to other algorithms. Overall, IFPA can provide better solutions with less power deficit and shows as a promising method for optimizing hydropower reservoir problems. [ABSTRACT FROM AUTHOR]

Accurate prediction of renewable energy generation acts as a critical role which not only provides short-term power generation in the future, but also facilitates scheduling and pre-configuration of energy storage systems. More importantly, the power generation prediction is of great significance to the demand response management (DRM) of renewable energy to participate in the electricity spot market. Therefore, DRM helps improve the stability and reliability of renewable energy systems. This paper presents a novel prediction-smoothing based methodology to reduce and eliminate the influence caused by the uncertainty of renewable energy output. Firstly, the Whale Optimization Algorithm (WOA) is combined with Long Short-Term Memory (LSTM) to predict short-term wind power output. Then, the Hampel-Butterworth-SG filtering strategy with outlier regression and specific risk band elimination is introduced. After that, according to the short-term output forecast results, the scheduling and pre-configuration scheme of peak-filling type energy storage is developed. Finally, based on the predicted renewable energy output and electricity price, the dynamic changes of demand response (DR) are calculated based on Logistics function, optimistic response and pessimistic response factors. Through extensive case studies, it is demonstrated that the assessment deviations in different scenarios is less than 5%, which are 0.64% for Scenario 1 and 3.64% for Scenario 2, and no additional penalty is required at this time. In addition, the proposed Demand Response Load Adjustment Rate (DRLAR) help compare the differences between predicted and actual DR, which are DRLAR = 0.03% in Scenario 1 and DRLAR = 0.01% in Scenario 2. Users are able to adjust the DR dynamically according to the electricity price to realize the optimal scheduling of their renewable resources. The proposed methodology creates a special connection between DRM and renewable energy prediction, which provides a reliable reference for future work. [ABSTRACT FROM AUTHOR]

World electricity consumption has grown permanently since 1990, dramatically increasing the emission of greenhouse gases. The worldwide efforts to reduce them and address climate change are leading to the massive electrification of different end-users, increasing the power demand. Therefore, achieving Sustainable Development Goals regarding affordable and clean energy requires the extensive availability of capital investments in electricity generation from renewable sources. Project Finance (PF) is a suitable financing alternative for large projects. This paper presents the advantages of PF contracts in allocating risks to appropriate counterparts and reducing the likelihood of default. Additionally, this study analyzes the characteristics that favor PF financing for renewable energy projects. The results reveal that country's governance levels, well-developed financial systems, and project costs affect the financing probability of a PF initiative, particularly for low and middle-income countries. Therefore, public policies aimed at increasing the availability of resources to renewable projects must tackle these factors. • The world requires massive renewable energy investments to meet Sustainable Goals. • Project Finance is a widely financing structure for large investment projects. • We study the determinants of renewable energy Project Finance. • Low governance and financial development hinder renewable energy PF initiatives. • Policies to develop capital markets and PF will help to reach the net zero target. [ABSTRACT FROM AUTHOR]

In this paper, the authors present a two-step model to obtain quasi-optimal solutions for the storage and transportation of renewable energy as its installation becomes more widespread in remote areas. The model is formulated as a total cost minimization linear programming problem and considers both renewable energy facilities and the energy supply and demand of the entire country. The first step of the model optimizes the entire country, while the second step determines the marginal capacity of energy storage and transportation facilities when the excess production capacity of remote renewable energy is added. This approximation for reducing computational complexity is shown to be sufficiently accurate under realistic conditions. The authors apply the model to analyze energy storage and hydrogen production at renewable energy power plants in Japan in 2050. The study shows that photovoltaic power generation uses storage batteries attached to the power plant for electricity transmission. In contrast, wind power generation transmits most electricity directly without storage batteries and converts some into hydrogen for consumers. The proposed lightweight model allows for numeral sensitivity analyses, which provide valuable insight into optimizing energy storage and transport of renewable energy. • We developed a 2-step model for quasi-optimization of equipment at VRE site. • This model optimizes energy storage and transport with VRE deployment. • If additional VRE is sufficiently small, the model division retains sufficient accuracy. • Energy supply costs minimized by combining power transmission and H 2 transportation. • PV has large LIB, while WT has direct transmission and H 2 production. [ABSTRACT FROM AUTHOR]

The number and importance of renewable energy communities (RECs) are increasing in all European countries due to the support of EU and national policies in order to foster the energy transition through participatory strategies for distributed energy systems. However, their development is rather slow in some countries, including Italy. The paper addressed the issue of the emergence of these socio-technical configurations in Italy, after the related law which entered into force in 2020 allowing the possibility of creating them. Our study focused on the alliances among different actors (professionals, institutions, NGOs, citizens) highlighting possible trends or models for the future that need to be confirmed in further research. The approach proposed to analyse this current process is the Actor-Network Theory, aiming at drawing the assemblages of human and non-human actants at a general level. Accordingly, we selected three case studies in order to show their different ways of organising, the relevance of trust in establishing each REC and the influence of local context on the composition and features of the actor-networks. [ABSTRACT FROM AUTHOR]

Developing new technologies to utilize natural renewable energy resources and fluxes is critical to mitigate climate change and energy crisis. As a renewable energy resource, wave energy is more predictable and has a higher power density compared to solar and wind. However, the technology for wave energy harvesting is still relatively nascent. One of the major challenges as the sector developers is the lack of spatial–temporal representation of wave resources, or wave power generation, from a generic WEC. This paper proposes a novel Wave Net Power Assessment (WNPA) method by utilizing the theoretical Wave Energy Converter (WEC) power limits (including the radiation power limits, Budal's limit, and gross wave power), and applies it to a decade of wave conditions across the USA East Coast, West Coast and Hawaiian Islands. The WNPA method assesses the wave resource from device point of view (unlike traditional gross wave resource assessment) and is generally applicable to WECs regardless of dimension, size, and degrees of freedom (DoFs). The geospatial application of the WNPA method allowed for the analysis of wave power production potential along U.S. coastlines and provides WEC developers meaningful data to make decisions about the best spatial region to deploy certain WECs. Numerical simulations are conducted for WECs with 5 different sizes, 3 different operating modes across the West Coast, East Coast, and Hawaii over 10 years. In addition, productivity, efficiency and gross power quality comparisons are made in terms of the size and degree-of-freedom for WECs deployed at certain ocean sites (e.g., PacWave). A few of the most important findings: (1) The net wave power is dramatically smaller than the gross wave power, which indicates the new WNPA method has a more conservative assessment of the wave power potential; (2) A heaving 10 m WEC is found to have the highest (compared to other sizes and degrees of freedom) absorption efficiency on the West Coast and Hawaii; (3) For smaller 2 m surging/pitching WECs, ocean sites on the East Coast (e.g., Diamond Shoals, NC) maximize power production. (4) There are distinct trade-offs between maximizing power or minimizing power quality and dependencies exists between the location of interest, the WEC size, and the priority degree of freedom. The proposed methodology can be utilized by WEC technology and project developers to conduct apriori preliminary analysis of WEC deployment locations and device characteristics. • Introduction of novel Wave Net Power Assessment (WNPA) methodology for assessing the wave energy resource by providing an upper practical limit of WEC power generation. • Derivation of generic methodology to predict the performance of a WEC; depending only on WEC characteristic dimension and mode of motion. • Geospatial analysis of WEC generation across the US West Coast, East Coast and Hawaiian Islands with five differing WEC sizes, with three different degrees of motion, over a 10-yr period. • Quantification of the mean power, conversion efficiency and co-efficient of variation over a decade. • Ability to quickly understand the spatial and temporal monthly variability of various WEC archetypes in specific locations within US waters. [ABSTRACT FROM AUTHOR]

Wave energy is a huge renewable energy resource with great potential for development. It can be used to power monitoring sensors on offshore work platforms and bridges. In this paper, a novel piezoelectric wave energy harvester based on cylindrical-conical buoy structure and magnetic coupling (C-PWEH) is proposed. As the wave oscillates up and down, it drives the buoy up and down and forces the piezoelectric patches to deform under magnetic force, thereby collecting the energy from the wave. The efficiency of the wave energy conversion can be improved by optimising the design of the buoy. With magnetic coupling, the low-frequency wave motion can be converted into high-frequency vibrations of the piezoelectric patches thus enabling the device to achieve a better output performance. Experiment findings reveal that the C-PWEH may deliver effective energy production when subjected to wave excitation. When the best matching resistance is 5000Ω, the maximum output power of 41.5 mW can be obtained. Under the optimal experimental parameters, 82 LEDs can be illuminated and power storage tests are performed using capacitors, further demonstrating the feasibility of the C-PWEH powering some low-power sensors. [ABSTRACT FROM AUTHOR]

The fundamental way for China to achieve carbon peak and carbon neutrality is to continuously improve the penetration of renewable energy (RE) in the power system and establish an electricity mix dominated by RE power. According to China's 14th Five-Year Plan, the proportion of non-fossil energy power generation should reach about 39% by 2025. However, the impact of the increase in share of RE power on carbon emissions of the electricity sector remains to be estimated. To this end, the purpose of this paper is to capture the nonlinear characteristics of RE on electricity-related carbon emissions by using panel smooth transition regression (PSTR) model and provincial panel data covering the period 1991–2020 under the background of provincial RE quota system. The estimation results indicate that, (i) in the four transition variables of PSTR model such as the installed capacity of power generation, substation equipment capacity, total electricity consumption and total power generation, the nexus between RE deployment and electricity-related carbon emissions was detected as nonlinear. (ii) The heterogeneous RE carbon abatement effect is reflected in its increasing penetration in provincial power systems. (iii) Carbon abatement performance of RE generation decreases in the negative range with the increase of transition variables. (iv) The estimation coefficient of RE is positive at the higher value of the transition variable in the PSTR model of carbon emissions per capita. As a result, the RE quota with the best emission abatement performance should be designed based on the provincial power resource endowment and the medium and long-term expected electricity consumption. [ABSTRACT FROM AUTHOR]

The increase of Renewable Energy (RE) production to fight the climate crisis is posing new technological and financial challenges, due to the availability and variability of RE Sources (RES). These challenges can be addressed by selecting the most suitable mix of RES to optimise power production, to assure grid resilience and to promote local energy use. To facilitate the selection of such combination, this paper presents an original methodology that allows to compare mixing scenarios with different RES, also in presence of batteries and backup system. It simultaneously optimises the energy surplus with respect to the eventual external electrical load and the missing energy with respect to the same electrical load. This method, which can cope with isolated or plugged-to-grid systems, is here applied to a novel case study, an oil&gas platform under decommissioning, located in the Adriatic Sea (Italy). The RE production from wind, wave and solar panels is supposed to support other activities for the platform reuse, such as aquaculture, monitoring and mineral deposition. In this case, solar energy is providing the greatest contribution to the optimal mix in terms of production, while wave energy assures the most relevant contribution in terms of continuity. [ABSTRACT FROM AUTHOR]

This paper aims to examine the relationship between oil prices and the indices of renewable energy and technology companies using Quantile Regression (QR.), Quantile-on-Quantile Regression (QQR), and Granger-Causality in Quantiles (GCQ) techniques. The results show strong evidence of an asymmetric effect at the sum of oil prices and technology companies' index on clean energy, indicating that the relationship is vital when these variables decrease than increase. The main finding of the QQR method demonstrates that the impact of oil prices and the technology stock index on clean energy is higher at the upper quantile than the lower quantile. We also establish bi-directional GCQ indicating the considerable change in oil price led to a change in renewable energy; besides, the outcome of the change in renewable energy does not support the causal link to the variation in oil prices across lower extreme quantile at 1%. Finally, our findings support the bi-directional causality from the tech companies market to the conventional and unconventional energy markets. Results identify the substantial role of renewable energy, with implications for global policy, decision-makers, and fund managers. [ABSTRACT FROM AUTHOR]

In this paper, we explore the co-movements between renewable and non-renewable energy sources and CO 2 emissions and GDP per capita in Saudi Arabia, respectively. Using the spectral Granger causality approach, our results suggested that non-renewable energy sources lead to carbon emission expansion in the frequency domain. Taken together, a significant causal relationship from fossil to economic growth is perceived over the long-term horizon while renewable energy source drives economic growth over different frequencies and considerably contributes to carbon emissions reduction. The wavelet plots revealed strong discrepancies in all variables in the time-frequency space. While non-renewable energy sources indorsed the economic growth across short-and medium-term scales and contribute to a polluted environment, renewable energy consumption has a substantial effect on carbon emission drop and on economic growth in the short-term. The multiple wavelet outcomes show that renewable energy may not only stimulate the economic growth but also promote sustainable and cleaner environment. The combined effects of non-renewable energy sources rise the carbon emissions. Thus, Saudi's government is counselled to promote the green energy investments and accelerate the transition to renewable energy production as its use as a substitute of fossil fuels carries advantages and opportunities alternating from environment to social-economic. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of information and communication technology (ICT), a subset of many functions such as visual communication, can positively affect renewable energy development in different countries. In this paper, focusing on China as the world's largest emitter of greenhouse gases, the relationship between visual communication and the deployment of renewable energy is investigated using the dynamic ARDL (autoregressive distributed lag) method and annual data from 1990 to 2021. Regarding the empirical estimations, a 1% increase in green finance market size leads to an improvement of sustainable energy deployment by 0.01%. In addition, the ICT development index has a significant and positive effect only in the long term. Furthermore, there is evidence of uni-directional causality from ICT to renewable energy deployment in the medium and long term. The recommended practical policies by the research are developing green financing tools, green economic growth policies, and creating virtual portals for financial interactions. • There is uni-directional causality from visual communication to renewable deployment. • ICT development index has a positive effect in the long term. • Effect of GDP on the development of renewable energy consumption is negative. [ABSTRACT FROM AUTHOR]

With the increasing penetration of renewable energy, the traditional energy storage operation based on individual framework —users own and operate independently mode may become impracticable due to conflicting interests, insufficient utilization, and poor interoperability. Riding on the wave of the proliferation of sharing economy, storage energy sharing expands the existing storage energy without requiring costly and time-consuming infrastructure investments. However, the development path of shared energy storage (SES) mode is not clear due to the asymmetric decision-making of the owners of energy storage systems under bounded rationality. In this paper, the diffusion of the business model of SES among multiple renewable energy stations (the owners, RES) and its key factors are analyzed based on the evolutionary game. The goal is to maximize social welfare and ensure the continuous growth of the sharing market. The numerical simulation is carried out based on the data from northwest China to interpret the development path. The result shows that, in renewable energy cluster the stations with intermittent output or with the higher prediction accuracy are more willing to participate in sharing. The energy storage sharing mode fails when the energy storage capacity ratio of RES is less than 10%. While the high-level ratio (more than 30%) is not conducive to the diffusion of the sharing model in RESs with low power generation prediction accuracy. [Display omitted] [ABSTRACT FROM AUTHOR]

Many subarctic communities rely entirely on fossil fuels for their energy needs. Solar-assisted ground-coupled heat pumps (SAGCHP) can be a solution to integrate renewable energy sources into their energy portfolios. However, it is currently unknown how such systems could operate in the context of the high North (cold ground, extreme mismatch between insolation and heating need, electricity from diesel). The objective of the paper is to develop a detailed model of a SAGCHP heating a house in Nunavik (Quebec, Canada) in order to gain a better understanding of its potential and limitations. The solar assistance is provided by PVs. Simulations with and without electric storage (batteries) were run. A complex tradeoff between four different modes of operation was obtained depending on the conditions of the system at each time step. For the test case, results show that the ground experiences a weak long-term thermal depletion partly compensated solar energy, but that a significant portion of the PV power production is preferably used by the compressor or stored in batteries rather than stored in the ground as heat. Over ten years, the SAGCHP system reduced fuel consumption respectively by 38.2% (without a battery) and 59.1% (with a battery). [ABSTRACT FROM AUTHOR]

By considering the significant role economic growth has played in environmental function between 1990 and 2019, this paper examines the relationships between renewable energy development, trade openness, and institutional quality in the development of green finance in South Asian countries. The effectiveness of institutions and trade transparency are factors in green finance. We use a panel data model to ascertain the cointegration among the variables. The study employs the OLS fixed pool method along with a quantile regression to assess the model and reveal that, although growth in renewable energy development and trade openness worsen the ecological environment, institutional quality and the use of renewable energy promotes green finance development. The findings indicate that trade openness and institutional quality have a positive link with green financing. Institutional quality drives the use of renewable energy, whereas gross domestic product (GDP) drives the environmental impact. In light of these findings, policymakers can put in place beneficial policies for renewable energy development as an economic instrument to minimize ecological footprints and enhance green finance development. • Trade openness. • Renewable energy development. • Green finance. • Institutional quality. [ABSTRACT FROM AUTHOR]

The increasing penetration of renewable energies in power systems demands new services from renewable generation plants. System operators are concerned about system stability since renewable generators behave as constant power sources. Therefore, new requirements have been imposed to grid-following generators to improve their contribution to system stability acting as grid-supporting generators. Nevertheless, grid-supporting control can still compromise system stability for high penetration of renewables, and grid-forming control has arised to ensure proper operation. This paper proposes a novel grid-forming control scheme for doubly-fed induction generators, so they behave as real voltage sources. The proposed grid-forming control is based on the rotor flux orientation to a reference axis obtained from the emulation of the synchronous generator swing equation. The rotor flux is oriented to the reference axis by means of a flux controller that also controls the flux magnitude. The flux orientation in turn allows to control the doubly-fed induction generator torque, while the flux magnitude control allows to regulate the generator reactive power or terminal voltage. The proposed control system has been validated through a comprehensive real-time simulation with hardware in the loop, assessing its grid-forming capability. Moreover, small signal analysis has also been performed to assess system stability. [ABSTRACT FROM AUTHOR]

There is some new challenges about the greenhouse gases, climate changing, and weather warming. The applying of the various Energy Policies (EPs) on production sections, is the prevalent solution that considers promotion of the renewable energies. The result is enhancement of penetration rate of the Renewable Energy Sources (RESs) in the power systems. However, till now, there are little papers that assessed the effects of EPs on the social welfare. The social welfare consists of the financial profits of the RES production company as well as the surplus welfare of subscribers. In this paper, the results of the implementation of a well–known EP as the Renewable Energy Certificate (REC) and its effect on the surplus welfare are assessed, based on the Generation Expansion Planning (GEP). In order to obtain the paper aims, the desired EP and the GEP are mixed, and a comprehensive model is presented from the perspective of an RES production company. The model is solved in the form of a Mixed Integer Non–Linear Problem (MINLP) in the GAMS optimization software using the BARON optimizer. Also, in order to reach complete solution, two scenarios as without and with the proposed EP are considered, and the results are compared with other EPs. For evaluation of the social welfare, a criteria as the Virtual Price Index (VPI) is introduced. With analysis of the results, it could be seen that the surplus welfare of the subscribers increases in the long term horizon, while it was lower than profit of the RES production companies at short terms. • Using of REC-EP to study the GEP, in presence of RES units. • Analysis the SW, social welfare, and the company profits under REC-EP. • Using of robustness method, MINLP, to solve the problem, considering real limits. • Comparing the first scenario results with other methods secured proposed method. • Comparing REC-EP results with others in the second scenario shows its high worth. [ABSTRACT FROM AUTHOR]

The use of renewable energy sources is increasing worldwide to achieve energy production sustainability. To reach this goal and mitigate against climate changes all energy resources must be optimally managed. In this paper, an innovative multi agent-based heuristic optimisation system is developed to address renewable energy systems' challenges associated with the management of renewables including storage devices, planning of energy distribution, and consumption flexibility. A new heuristic algorithm is developed to introduce an efficient and sustainable storage strategy of surplus energy generated by different renewable resource options. This leads to archiving optimised storage levels of energy across different located storage devices in order to face risk of production shortages due to weather conditions. In order to test the behaviour of the developed system and address its benefits, a case study in the Republic of IRAQ is developed. Twelve major cities (in order of population size) distributed in 5 main regions including North, South, East, West and Middle parts of the country are selected, and hybrid renewable power generation sources such as Wind, PV-solar and Hydro are implemented based on weather changes. The results highlight the effect of high suppliers' rate on electricity exchange and production planning from differently used renewable technologies. A sensitivity analysis is conducted to verify the behaviour of the developed model on different demand behaviour types. • This paper considers a complex renewable energy production-distribution problem. • This study proposes an agent-based model to satisfy consumers' demand of energy. • A new heuristics algorithm to provide a sustainable storage strategy of energy. • Simulation result presents optimal energy production and minimum level of shortage. [ABSTRACT FROM AUTHOR]

Non-dispatchable Renewable Energy Sources (RES) changed energy production from being centralised and fully dispatchable, to be more decentralised and less predictable. Despite the substantial growth, RES must be increased to fulfil the power production decarbonization targets set by several countries. In several countries, Italy included, RES development must be based on solar PV. Thus, relevant energy quantities will be shifted from day hours to night hours. Such "Load Shifting" is done with energy storage technologies. A few technologies suited for this task are already available, whereas several others have been proposed, but not tested in the practice. In this paper, such storage technologies are reviewed focusing on the performance and costs. Based on the review, current and future storage economic outlooks are assessed by focusing on the Italian scenario. In the paper, the storage operation is optimized at the hourly level to calculate the maximum achievable annual revenue. The optimisation is performed with a linear programming (LP) approach. Since none of the reviewed storage is economically feasible, the energy price modification required to achieve feasibility are estimated. Based on such results, the distance between the current situation and the one favourable to storage is assessed. In this way, the future outlook of each storage technology is discussed. • A review of storage technologies suited for grid-scale applications is presented. • The data from the review are used for an economic feasibility analysis. • The revenue is maximised over a year through a linear programming problem. • The cost over revenue ratio quantifies the required incentive from support schemes. • The energy price modification required to make any storage feasible is discussed. [ABSTRACT FROM AUTHOR]

The growing energy demand places its focus on renewable energy resources as a sustainable energy resource. Wind Power is one of the important sources of renewable energy. However, it exhibits challenges in the form of stability and control when integrating with the conventional grid. Though the connection of wind power plants does not require any major redesign, it is, however, necessary to ensure that issues are taken care of through control and compensative devices, to enable the grid to recover from grid faults and system disturbances. One such proposal is discussed here. This paper analyses the design and implementation of Proportional-Integral (PI) controlled Static Synchronous Compensator (STATCOM) controllers and is compared with Fuzzy Logic Controlled(FLC) STATCOM controllers. These controllers are primarily used to stabilize the voltage in wind power plants by preventing tripping of Wind Generators (WG) in the event of a grid side disturbance or fault and can recover from the fault by injecting reactive power in the grid. This paper applies STATCOM for restoring the voltage levels at the terminals of the wind power plants and simulated using MATLAB Simulink. It is observed from the simulation results, that STATCOM with fuzzy logic controls tends to reduce the voltage fluctuation and ensure the stability of the system as compared to STATCOM with PI. • STATCOM with PI controller improves voltage regulation. • Enhanced performance with the usage of STATCOM with Fuzzy Logic controller. • Enhanced gain stability in the event of network disturbances. • Improves transient performance. [ABSTRACT FROM AUTHOR]

Short-term forecasting of electricity generation from variable renewable energy sources is not an end in itself but should provide some net benefit to its user. In the case of electricity trading, which is in the focus of this paper, the benefit can be quantified in terms of an improved economic outcome. Although some effort has been made to evaluate and to improve the profitability of electricity forecasts, the understanding of the underlying effects has remained incomplete so far. In this paper, we develop a more comprehensive theoretical framework of the connection between the statistical and the economic properties of day-ahead electricity forecasts. We find that, apart from the accuracy and the bias, which have already been extensively researched, the correlation between the forecast errors and the market price spread determines the economic implications - a phenomenon which we refer to as 'correlation effect'. Our analysis is completed by a case study on solar electricity forecasting in Germany which illustrates the relevance and the limits of both our theoretical framework and the correlation effect. • The economics of short-term electricity forecasts are studied analytically and empirically. • The value and the risk of forecast-based electricity trading are evaluated. • We find that the economics depend on the correlation of forecast errors with prices. • Hence, the most accurate forecast is not necessarily the most accurate. [ABSTRACT FROM AUTHOR]

The primary purpose of this paper is to evaluate the impacts of green finance on green energy deployment in China's tourism industry. To this end, the annual data over 1992–2021 through the ARDL (Autoregressive Distributed Lag) approach for the case of China are analyzed. The findings confirm that the issued green bonds positively impact the green efficiency of China's tourism industry in the long term. In contrast, the coefficient of issued green bonds is insignificant for the short-term approach. In addition, in the short and long term, the consumer price index also has a significant adverse effect on the green efficiency of China's tourism industry. The recommended practical policies are improving executive regulations and transparent market information, implementing green fiscal policies, green construction in hotels and tourist accommodations, green globalization, operational phases of innovation, adaptation, and stabilization (IAS), and eco-tourism regionalism. • Green bonds have a positive impact on the green efficiency of China's tourism. • Consumer price index has a negative effect on green efficiency of China's tourism. • Economic globalization index has a significant coefficient on green efficiency. [ABSTRACT FROM AUTHOR]

The lack of partnerships between biomass generating producers is one of the main barriers to efficient biogas production. Partnerships can help producers properly dispose of waste, assist in the supply of biodigesters, allow the union of properties with different potential biomass generators into clusters, and optimize operating costs. In this sense, new measures must be adopted with regard to the establishment of strategic partnerships between producers. Therefore, in this paper, we propose a new clustering algorithm, BiogasCluster , to decide the optimal number of clusters for generating a renewable energy community. To test the proposed algorithm's applicability, we implemented the algorithm in R language. Experiments with real databases showed that the BiogasCluster proved to be efficient in generating stable clusters for all considered scenarios. It was also found that the filters and criteria used in the proposed algorithm have not been used in previous studies. This study provides important guidance to creating strategic partnerships within bioenergy generation in addition to obtaining a preliminary assessment of the possibility of establishing clusters of rural properties with the aim of achieving energy security and adding value to their businesses. [ABSTRACT FROM AUTHOR]

This paper investigates the validity of the environmental Kuznets curve (EKC) hypothesis for the G7 group of countries through the ecological footprint and its components (namely built-up land, carbon, cropland, fishing grounds, forest land, and grazing land). Most previous contributions rely on CO 2 emissions as a measure of environmental damage, whereas using disaggregated ecological footprint allows us to consider resource consumption and waste generation compared to nature's resource generation and waste absorption. The empirical application is based on a panel data analysis for G7 countries from 1980 to 2018. The results indicate that the EKC hypothesis is confirmed for the ecological footprint overall, but the impact of GDP growth is unequal across its components. Long-term elasticities point to renewable energy generation significantly improving environmental sustainability. Globalization also decreases pollution indicators, while economic complexity seems to contribute to environmental degradation. [ABSTRACT FROM AUTHOR]

Renewable energy attracts increasing attention from both industry and academia under the context of carbon neutrality. For wind and solar energy, the strong dependence on natural processes results in the imbalance between energy production and real demands. Energy storage technologies, e.g., Compressed Air Energy Storage (CAES), are promising solutions to increase the renewable energy penetration. However, the CAES system is a multi-component structure with multiple energy forms involved in the process subject to high temperature and high-pressure working conditions. The CAES system is a complex process flowsheet consisting of charging and discharging process. The process should be optimized to achieve the best thermodynamic and economic performance. Under the optimal design conditions, it might lead to severe consequences once a failure occurs, e.g., harm to humans, the environment, and assets. Limited attention and scarce available information have been paid to the CAES system risk management yet. Hence, this paper applies the System-Theoretic Process Analysis (STPA), which is a top-down method based on system theory, to identify the CAES system safety hazards. The results are expected to provide a preliminary guideline for practitioners regarding the safety and reliability of the CAES system. As a result, a more reliable CAES system can contribute to a more flexible energy system with more efficient and economic utilization of fluctuating renewable energy. [ABSTRACT FROM AUTHOR]

Over the past decades, the penetration of renewable energy sources is growing at a significant pace on a global scale. In parallel, the utilization of renewables could possibly act as the basis for the transition to a Circular Economy, which aims to reduce the use of finite resources. Compared to other European countries, Greece has achieved a significant share of renewables in its' energy mix and in parallel promotes various policies aiming to accomplish zero-carbon emissions by 2050. An important element of this procedure is the broader acceptance of renewables by the public. This paper investigates this concept by capturing citizens' view on renewable energy sources along with the overall concept of Circular Economy in Greece. By implementing a questionnaire analysis, empirical findings capture the intention of citizens to further develop and invest on renewable energy. Besides, our analysis identifies that as education level increases, the willingness to pay more for renewables and their acceptance from the public increases, as well. Finally, empirical findings indicate that Greek citizens are aware of the concept and the benefits arising from Circular Economy, yet additional efforts need to be addressed for the growth of this concept in Greece. • The study captures citizens' view on RES and Circular Economy in Greece. • Participants are aware and sensitive on environmental and climate change issues. • Participants accepted the existence of RES and are willing to pay additional cost. • As the level of education increased, willingness to pay for RES also increased. • Additional efforts need to be addressed for the growth of Circular Economy in Greece. [ABSTRACT FROM AUTHOR]

The emergence of new technologies, such as photovoltaic (PV) solar systems, household Battery Energy Storage Systems (BESS) and electric vehicles (EVs), has introduced challenges for the Distribution Network Operators (DNOs) in the operation of power distribution networks. Uncontrolled renewable energy generation and storage, and EV charging can cause over/under voltage problems. Recently, there has been much effort, from control and scheduling of BESSs and EVs to PV curtailment, to address these issues. However, the knowledge about how much penetration of these technologies can be well-tolerated by the grid when all charging/discharging are uncontrolled, would still be of interest to DNOs. There are many depending factors such as customer consumption profiles, grid conditions and network constraints. In this paper, we propose a framework to determine the critical balance between PV, BESS and EV in a distribution grid. Using real data from 4000 customers in Victoria, Australia, we find that in the absence of advanced control and scheduling algorithms, the best approach to prevent voltage violation in the grid is to keep the installation of PV and BESS balanced with the EV penetration. We also show that power export to the grid by EVs using the vehicle-to-home (V2H) technology may contribute to keeping the grid voltage in the standard range if 40%–80% of EVs are in the discharge mode in critical peak times. While complete coordination of PV, EV and BESS has not yet been fully realized in many networks, our methodology provides a framework for DNOs to perform optimised planning. [ABSTRACT FROM AUTHOR]

The combination of biomass and solar energy in the combined cooling heating and power (CCHP) system is conducive to reducing carbon dioxide emissions of the system. To improve the system's economic performance under the punishment of carbon tax, this paper optimizes the system from system design and operation strategies. A hybrid renewable energy CCHP system with shaft power distribution structure of an internal combustion engine (ICE) is proposed. By optimizing the shaft power distribution of ICE, the direct drive heat pump is realized, and the efficiency of the shaft power of ICE is improved. A double-layer optimization method considering the long and short-term benefits is proposed based on the system, fully improving the system economy in design and operation. The case study shows that the CCHP system reduces the annual cost by 40.37% and the CO 2 emission by 88.93% compared with the separate production system. Compared with the non-shaft power distribution system, the maximum daily operation cost is saved by 557.11CNY. Compared with the hourly optimization method, the proposed optimization method based on total daily benefit reduces the annual cost by 7.73% and CO 2 emission by 35.87%, and the utilization rate of the energy storage device is higher. [ABSTRACT FROM AUTHOR]