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Optimizing energy management for distributed renewable energy sources (DRESs) with battery energy storage systems, energy trading, and emission trading schemes (ETSs) within the Internet of Energy (IoE) has garnered considerable attention. ETSs have been extended to include sectors with dispersed emissions, notably targeting households, aligning with the growing adoption of DRESs for household electricity. However, previous studies focused on how renewable portfolio standard (RPS) that mandates energy suppliers to include a percentage of renewable energy into their energy portfolios influence industrial and large-scale energy systems, neglecting the potential of implementing RPS at the household level. In addition, previous studies analyzed energy markets of traded green certificates (TGCs), certified through their separation from renewable energy generation, but rarely investigated their potential within households. Consequently, this study introduces house-based RPS (HRPS) and the unbundling of TGCs into a dynamic energy management optimization problem for a smart house with DRESs, a home energy storage system (HESS), and an electric vehicle, where HRPS mandates daily consumption of green energy, allowing for energy and TGC trading through their respective trading platforms. A mathematical programming model is formulated for determining HESS charging/discharging decisions, energy trading, and TGC trading under HRPS, while minimizing costs and penalties for HRPS non-compliance. Since TGC unbundling makes this model much complex, a hybrid simplified harmony search (SHS) and double-adaptive general variable neighborhood search (DAGVNS) algorithm is proposed. Simulation results demonstrate that the introduction of RPS and TGC trading can effectively reduce the smart house's carbon emissions by approximately 19.4 % weekly. [Display omitted] • House-based renewable portfolio standard (HRPS) is included for more emission cuts. • Unbundling of traded green certificates (TGCs) enhances household energy markets. • Energy optimization of a house battery, energy, & TGC trading under HRPS is modeled. • Hybrid SHS and DAGVNS is devised to tackle model complexity due to TGC unbundling. • This method with HRPS and TGC unbundling reduces house emissions by 19.4 % weekly. [ABSTRACT FROM AUTHOR]

The number of poultry in Türkiye constituted approximately 24 % of Europe's total in 2020. Although Türkiye has a significant number of poultry animals, it has been relatively unsuccessful in terms of managing the associated poultry waste. The present study focuses on poultry manure-based biogas potential (PMBP), which represents an alternative means of poultry manure management in Türkiye. PMBPs were calculated for each year from 2003 to 2021, for which it was found that for 2021, Türkiye's PMBP had increased by 40 % since 2003, reaching 3469 GWh. The possible electrical energy savings that PMBP could provide for lighting, habitation, business, government offices, and industry throughout Türkiye were calculated, with PMBP spatial distribution maps for 2021 created according to geographical region and province. The province with the highest PMBP was found to be Manisa, at 390 GWh. The projected PMBPs were calculated to 2040 using the artificial neural network (ANN) and autoregressive integrated moving average (ARIMA). According to ARIMA, the PMBP for 2040 could potentially be increased by as much as 32 % from that of 2021, while according to ANN predictions, this same increase could be as much as 72 %. The ability to reduce greenhouse gas emissions resulting from poultry manure management in Türkiye through biogas production was calculated. Investors may need to prepare a feasibility study for the establishment of a biogas plant in a suitable region within Manisa province, as it has the highest PMBP among the regions evaluated. • Türkiye's biogas potential was estimated for 2040. • Türkiye's poultry manure based biogas potential is currently 3469 GWh. • Artificial neural networks were used to predict biogas in the coming years. • Emissions from Türkiye's poultry manure were calculated. [ABSTRACT FROM AUTHOR]

Paradigm transition towards green, clean and sustainable energy sources to reduce the global carbon footprint propelling the current energy market towards hydrogen economy due to the much reliable, carbon neutral and near zero emission properties though safe transportation and storage of hydrogen is a big challenge. Owing to its remarkable hydrogen content, easy storage and safe handling, NH 3 is the most suitable hydrogen carrier. Considering the energy potential of NH 3 , this review, focus on the thermocatalytic decomposition of NH 3 for CO x free production of H 2 on non-noble metal catalysts. Taking cost effectivity and scalability into account, recent development in design of inexpensive catalysts with metal components having less global warming potential are covered. A comprehensive survey and comparative assessment of recent (particularly post 2014) Co, Ni, Fe, Mo, metal carbides, imides, bimetallic and multimetallic catalysts with established benchmark catalysts is presented here. Effect of various promoters and supports on electronic properties, textural properties, reducibility and surface characteristics of catalyst is extensively reviewed. Mutual bimetallic synergism, novel synthetic approaches and reaction mechanism is also highlighted considering their role in successful execution of sustainable ammonia decomposition. A brief description of deactivation challenge of catalysts and measure taken to counter it is also given. Special emphasis is given to the catalysts which have potential of decomposition of ammonia at low temperature (<450 °C). Finally, summary and scope along with brief economic evaluation is presented targeting further development in large-scale production of H 2 from NH 3. [Display omitted] • Recent progress in non-noble heterogeneous catalytic NH 3 decomposition was reviewed. • Mutual synergism of supports and active metals promoted low temperature NH 3 decomposition. • Surface basicity, reducibility and spatial configuration were indispensable for highly active catalysts. • High affinity towards NH 3 and easy dissociation of reactive species (N∗ and H∗) were the key for efficient catalyst. • Special emphasis on novel strategies with economic perspective to design efficient catalysts. [ABSTRACT FROM AUTHOR]

This research work explores the conceptualization and evaluation of a hybrid microgrid that taps into the potential of solar photovoltaic systems, wind energy conversion systems, and battery energy storage systems. In practice, nonlinear loads pose power quality issues that significantly impact the performance of hybrid microgrids. To tackle these challenges, an adaptive multi-generalized integrator (MGI) filter is proposed. This filter extracts the fundamental signal from the distorted utility grid voltages. It features a pre-filter with a DC-off set rejection loop, effectively minimizing the DC-offsets from the distorted grid voltages. This facilitates the distribution of active power generated by the hybrid microgrid's sources while simultaneously addressing various power quality problems. In addition, a dynamic power management control approach enhances grid resilience by operating the hybrid microgrid in grid-connected and islanding modes. It provides uninterrupted and high-quality power supply to consumers during grid outages. The performance of this filter is comprehensively assessed through numerical simulations in MATLAB®/Simulink® environment. A real-time laboratory prototype is developed with WAVECT® WUC300 FPGA controller, demonstrating the practical application of the proposed filter. It ensures the minimum DC-offsets of 0.02V, fast convergence, and minimum oscillations. The grid synchronization and power quality index of the grid currents simultaneously achieve a THD of 2.82 %, complying with the IEEE-1547 and IEEE-519 standards. Importantly, the proposed adaptive-MGI filter outperforms the conventional SOGI and LMF filters in terms of nonlinear load tracking capabilities, with a response speed of less than 200μs, thereby highlighting its practical relevance and importance. [Display omitted] • Hybrid Microgrid is a reliable solution to cater to load demand. • Presented novel adaptive MGI-filer for the multifunctional operation of HMG. • A systematic procedure and development of the HMG system are presented. • The proposed controller offers reliable solutions to power quality and grid interaction of RES. [ABSTRACT FROM AUTHOR]

The growing global demand for further penetration of renewable energy sources has highlighted Offshore Wind Farms (OWFs) as a promising solution, particularly in Greece, due to its abundance of wind resources. To address the challenges of optimal OWFs location, this study presents an integrated approach that combines Multi-Criteria Decision-Making (MCDM) methods with a Geographic Information System (GIS). The potential offshore sites have been evaluated across various technical, environmental, legislative, and safety criteria, utilizing incomplete information weights derived from the Analytic Hierarchy Process (AHP). This approach accommodates inherent impreciseness in both the payoff table values and criteria weights, leading to the adoption of an extension of the VlseKriterijumska Optimizacija I Kompromisno Resenjee (VIKOR) method. The applied ranking process identified the most preferable sites in Greece, incorporating different decision makers' perspectives. The methodology ranked 35 distinct sites in the Greek sea, including, but not limited to, areas south of Alexandroupoli, east of Xerokampos Crete, and near the Gulf of Patras. The novelty of this approach could play a pivotal role in the development of offshore wind power production within Greece's energy transition context. Finally, the proposed framework can be easily generalized, replicated and adapted in any country, thus contributing to the optimal placement of OWFs at a global scale. [Display omitted] • GIS-based Multi-Criteria Decision Analysis for offshore wind farm site selection. • Integration of official data in diverse formats as feature layers in GIS application. • Experimental evaluation of the methodology for ranking available OWF areas in Greece. [ABSTRACT FROM AUTHOR]

Low-carbon energy transitions are being increasingly developed at sub-national or regional levels, forming, thus, energy regions. More energy regions have been formed as energy systems become more decentralized, and national governments devolve decision-making power to local authorities. Energy regions have been studied in several countries, but no study has yet overviewed these regions' variety, transition process, and governance approach. It is important to draw lessons for other cases worldwide, like coal and carbon-intensive regions, to understand what type of regions and how they have stimulated their energy transition. Thus, this study investigated i) the concepts of energy regions that have been published and ii) the way energy regions have transitioned in terms of governance arrangements and innovation processes. A systematic literature review was conducted covering forty-seven academic publications and three grey literature reports of energy regions in ten countries. This review covered three academic (sub-)disciplines: i.e. sustainability transitions, regional studies, and innovation studies. Results show five concepts of energy regions: city-regions, peripheralized regions, coal and carbon-intensive regions, learning regions, and renewable energy regions. The formed typology shows the possible transition pathways that regions can follow. Interestingly, only those energy regions that adopted social innovations had the potential to empower their region, its organizations, and its citizens. Finally, recommendations for practitioners in similar regions worldwide are outlined to help overcome obstacles and advance their low-carbon transition. [Display omitted] • A typology is built based on a region's institutionalization and transition stage. • Five energy region concepts and four transition pathways are identified. • Learning energy regions represent a transition phase where innovations are adopted. • Social innovation can be key to promoting citizen empowerment in energy regions. • Informal institutions can be key to overcoming limited resources in energy regions. [ABSTRACT FROM AUTHOR]

Hydropower is an important step towards a low-carbon society; however, its global potential is challenged by high sediment content in streams. In Pelton turbines, which are installed in high-head hydropower plants (HPPs), even fine particles cause substantial damage leading to reduced turbine efficiency and increased maintenance cost. This study reviews the complex problem of hydro-abrasive erosion in Pelton turbines, particularly advances in prediction of erosion and associated efficiency reduction, abrasive potential at a potential site, and mechanism of progressive erosion. For this purpose, the hydro-abrasive erosion in buckets and injectors of the Pelton turbines covering a wide range of design heads, capacities, sediment and operating conditions obtained from reported works were analysed. In the bucket, the cut-out, splitter and brim region are found severely affected due to erosion; while, nozzle outlet and needle tip region are majorly affected. The erosion in cut-out, widening of splitter, and distortion of jet from injector erosion are major reasons for Pelton turbine efficiency reduction. The synergic effects of erosion and cavitation is also presented. A modification in the erosion model for initial assessment of erosion potential at a site is proposed and its use for mitigation of erosion at untapped hydropower projects is also discussed. Finally, the optimization steps related to erosion at a site for both upcoming projects and operational HPPs are addressed in detail. In view of the projected increase in sediment yield from catchments due to climate change, this study provides insights into mitigating erosion in HPPs located in erosion-prone regions. [Display omitted] • A review of Pelton turbine components prone to erosion and underlying mechanisms. • Data of hydropower plants in erosion-prone locations around the world are analysed. • Estimation of erosion potential for both proposed and operating HPP is discussed. • Reduction in Pelton turbine efficiency as a consequence of erosion is discussed. • Research scope and mitigation steps for erosion in Pelton turbine are discussed. [ABSTRACT FROM AUTHOR]

Mitigating global warming requires the rapid deployment of renewable energy (RE) systems throughout all parts of the world economy. A crucial step for such deployments is the assessment of their social, economic and environmental impacts. By reviewing three hundred and sixty-nine studies, this work identifies and synthesises a myriad of social, economic and environmental aspects of RE technologies deployment that have been studied over the past decade. The review identifies barriers and drivers that have been found to be common across countries, and those where studies and/or local contexts have found contradictory results. Amongst social issues, trust and quality of institutional governance were found to be increasingly prominent themes of research and key drivers for RE deployment. The review also reveals a growing interest in attachment to place, but with contradicting findings for its negative or positive impacts. Amongst economic issues, the review found widespread agreement that, irrespective of the type of economy, countries continue to preferentially pursue economic growth through expanded production and innovation in fossil fuels. The review of the environmental impacts found that studies of RE deployments tend to focus on negative local impacts, leaving positive global benefits, such as mitigating climate change, as implicit, and that there are only a few studies on the environmental impacts of RE in developing economies. Two gaps that the review identifies as demanding future work are investigating the benefits of RE co-location in developing economies and redressing the underrepresentation of First Nations perspectives and participation in research and RE deployments. [Display omitted] • Review of social drivers and barriers to renewable energy deployment. • Review of economic drivers and barriers to renewable energy deployment. • Review of environmental impacts of renewable energy deployment. • Global trends, agreements, controversies and gaps over the last decade. [ABSTRACT FROM AUTHOR]

This study reports a comparative analysis of life cycle greenhouse gas (GHG, CO 2 -eq.) emissions of three fuel-type vehicles, viz. internal combustion engine (ICEVs), battery electric (BEVs), and hybrid electric vehicles (HEVs), from an Indian perspective. Vehicles in hatchback and compact sports utility vehicles (SUVs) categories were analyzed. GHG emissions in fuel life cycle (well-to-tank and tank-to-wheel) and vehicle life cycle were estimated using data from websites of OEMs and ministries of Government of India, and the GREET software. The vehicle life cycle constitutes a smaller fraction (15–20 %) of total life cycle GHG emissions for ICEVs and HEVs compared to BEVs (∼35 %). The vehicle cycle emissions of BEVs are higher than ICEV and HEV in both categories (52–63 % for hatchback and approx. 45 % for compact SUV). The fuel cycle emissions of BEVs are smaller than ICEV and HEV in both categories (29–34 % for hatchback and 32–40 % for compact SUV). The total life cycle GHG emissions of BEVs were lower than ICEV and HEV (15–17 % in hatchback and 17–25 % in compact SUV category) for the 2023 energy mix in India with a significant share of thermal route. With anticipated doubling of renewable energy sources in India by 2030, the total life cycle GHG emission of BEV will decrease by approximately 20 %. However, sensitivity analysis revealed that BEVs produce higher GHG emissions than ICEVs and HEVs until a minimum lifetime travel distance. Thermal power plant efficiency and battery lifespan also influence BEVs lifetime GHG emissions. [Display omitted] • Analysis of emissions in fuel life cycle (WTT and TTW) and vehicle life cycle. • BEVs have high vehicle cycle emissions and low fuel cycle emissions. • Life cycle GHG emissions of BEVs lower than ICEV and HEV for present energy mix. • 20 % reduction in total GHG emission of BEV with higher renewable energy share. • Thermal power plant efficiency and battery lifespan affect BEV emissions. [ABSTRACT FROM AUTHOR]

Microbial electrolytic cell combined with anaerobic digestion faces challenges such as unstable clean energy supply and inefficient cathode performance. The integration of low-cost, durable electrodes with renewable energy can enhance the microbial electrolytic cell sustainability. In this study, a metal-organic framework-modified electrode and intermittent renewable energy sources were used in the microbial electrolytic cell to treat swine wastewater. Additionally, hydrothermal carbon composite metal-organic framework were tested to reduce cathode costs and improve biocompatibility. Results showed that with 18 h of daily power from a hybrid wind-solar system, the metal-organic framework-modified cathode achieved the highest cumulative methane production of 305.11 mL/g-chemical oxygen demand and the highest net energy recovery. Increased microbial activity during the power-on period enhanced methane output and energy efficiency, making this energy supply method ideal for microbial electrolytic cells. This approach ensures efficient use of renewable energy, improving the economic feasibility of microbial electrolytic cells for wastewater treatment. The metal-organic framework-modified cathode also promoted biofilm growth, with an average thickness of 37.6 μm and enhanced microbial activity, likely due to its lower resistance and rapid current response. [Display omitted] • Clean energy intermittent power supply effectively reduced energy consumption. • A hydrochar composite MOF cathode was used for MEC-AD of swine wastewater. • Improved electrode and intermittent power supply mode improved methane production. • Enrichment of Methanoculleus at the HCM cathode improved digestion stability. [ABSTRACT FROM AUTHOR]

The economic viability of solar power has led to widespread adoption in homes and businesses. However, its intermittent nature requires integration with other renewables and storage solutions to achieve peak efficiency. This study delves into the in-depth review and analysis of mathematical modeling for determining the optimum capacity of solar power plants and their combination with the other sources based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method. The main contributions of this research include a) Presenting the most commonly used variables for optimizing PV-based combination sources in the literature. b) Utilizing text mining on a large database in addition to the PRISMA model to increase the comprehensiveness of the results. c) Presenting all the common objective models in the literature, and d) Conducting a comprehensive comparison of solving techniques. This research provides valuable insights into the status and development trends in optimal sizing for PV energy systems by providing future direction in the renewable sources combination area. • Export limitations and pricing policies significantly impact the optimal combination of facilities. • Using shorter time intervals for energy demand and generation enhances model accuracy and complexity. • The majority of objective functions used in the literature are financial in nature. • In off-grid scenarios, demand spikes are challenging. • Due to parameter stochasticity and uncertainty, heuristic algorithms are commonly used to solve the problem. [ABSTRACT FROM AUTHOR]

Solar radiation modification (SRM) is a possible deliberate approach to decrease or reflect incoming solar radiation with the goal of reducing global temperatures, which have increased over the last decades due to high atmospheric greenhouse gas concentrations. Stratospheric aerosol injection, specifically, has shown potential for successfully reducing global temperatures in climate model simulations. Despite the growing literature in the areas of climate change and SRM, their combined effects on renewable energy generation, a climate change mitigation strategy, have not been addressed. In this review paper, we synthesize previous literature on the possible effects of climate change and SRM on renewable energy resources (i.e. , wind energy, solar energy, biomass energy, and hydropower), review the status of climate change and SRM research, and explore potential effects of SRM on renewable energy primarily in the Continental United States (CONUS), but with global perspectives as well. We discuss the research challenges and impacts of SRM on renewable energy and conclude by discussing the potential implications of SRM for renewables for SRM governance and policy. This work is not advocating for or against SRM. It is highlighting an important potential impact for future decision makers. • Climate change is projected to have varying impacts on renewable energy sources. • Solar radiation modification could also impact renewable energy sources, if applied. • More research on solar radiation modification impacts on renewable energy is needed. [ABSTRACT FROM AUTHOR]

Renewable hydrogen is a flexible and versatile energy vector that can facilitate the decarbonization of several sectors and simultaneously ease the stress on the electricity grids that are currently being saturated with intermittent renewable power. But hydrogen technologies, are currently facing limitations related to existing infrastructure limitations, available markets as well as production, storage and distribution costs. These challenges will be gradually addressed through the establishment, operation and scaling-up of hydrogen valleys. Hydrogen valleys are an important stepping stone towards the full-scale implementation of the hydrogen economy with the target to foster sustainability, lower carbon emissions, and derisk the associated hydrogen technologies. These hydrogen ecosystems integrate renewable energy sources, efficient hydrogen production, storage, transportation technologies as well as diverse end-users within a defined geographical region. This study offers an overview of the hydrogen valleys concept analyzing the critical aspects of their design and the key segments that constitute the framework of a hydrogen valley. Α holistic overview of the key characteristics of a hydrogen valley is provided whereas an overview of key, on-going hydrogen valley projects is presented. This work underscores the importance of addressing challenges related to the integration of renewable energy sources into electricity grids as well as scale-up challenges associated with economic and market conditions, society awareness and political decision-making. • Hydrogen valleys are gathering hydrogen production, storage and end-use technologies within a defined geographical region. • Hydrogen valleys are expected to integrate various renewable energy sources and ease stress on electricity grids. • A current status of hydrogen valleys is provided along with critical challenges and the path forward. [ABSTRACT FROM AUTHOR]

Greenhouses play a crucial role in food production and economic growth in northern regions but contribute significantly to energy consumption and carbon emissions. To address this challenge and enhance food production sustainably, there is a growing need for efficient and renewable energy solutions. Low-carbon heating in greenhouses will be achievable by using heat pumps powered by cost-effective renewable energy sources such as photovoltaic systems. This study introduces an open-source quasi-steady-state thermal model for greenhouses, non-ideal air-source heat pumps (ASHPs), and ground-source heat pumps (GSHPs) with both vertical (V) and horizontal (H) ground heat exchangers. Additionally, a ventilation sub-model is provided to manage cooling loads for residential, semi-commercial, and commercial greenhouses. Furthermore, an open-source SAM-Python-based photovoltaic system model is developed to size photovoltaic arrays for powering the heat pumps. The study reveals a nonlinear relationship between greenhouse size and annual thermal loads. It also demonstrates that ASHPs exhibit the lowest efficiency (COP h = 2.52, EER c = 9.00), followed by VGSHPs (COP h = 3.68, EER c = 19.88), with HGSHPs being the most efficient (COP h = 3.79, EER c = 19.48) for the Canadian case study. The required on-grid photovoltaic ratings to power HGSHPs, VGSHPs, and ASHPs respectively are 2.16, 2.17, and 2.64 kW for residential, 103, 104, and 128 kW for semi-commercial, and 827, 831, and 1,028 kW for commercial greenhouses. Self-consumption of designed photovoltaic systems ranges from 23.5 % to 25.1 %, with self-sufficiency varying between 23.7 % and 26.0 %. The size of the photovoltaic system is competitive with similar scenarios; however, future studies are needed to conduct an economic analysis while simulating the dynamic loads of greenhouses. [Display omitted] • Heat pumps (HPs) promising solution to provide low-carbon efficient heating in greenhouses (GHs). • Open-source quasi-steady-state greenhouse thermal model and ventilation sub-model for cooling. • Air-source heat pump (ASHP), ground-source heat pump (GSHP). • GSHP with both vertical (V) or horizontal (H) ground heat exchangers. • Case study is provided for Canada to power the HGSHP, the required on-grid PV ratings for 3 sizes of GHs. [ABSTRACT FROM AUTHOR]

Renewable energy sources, such as solar, wind, water and geothermal are abundant and replenished by nature, making them crucial for both present and future sustainable energy needs while significantly reducing greenhouse gas emissions, environmental pollution and can mitigate adverse climate change. This review work focusses on the recent applications of nanotechnology in energy production from renewable and sustainable energy sources. The recent advances in the application of nanoparticles and their nanofluids in solar panels, waste heat recovery, fuel cells, wind and hydropower turbines, and geothermal energy are discussed in detail. Moreover, this review highlights the role of nanotechnology in the conversion of biomass to bioenergy and biogas upgrading techniques. In addition, contribution of nanotechnology in carbon dioxide capture via various methods have also been discussed, which is closely associated with renewable energy production. This research reviewed various nanofluids for heat transfer across different equipment used in renewable energy production, comparing their performance to aid in nanoparticle selection for specific tasks. The review article explicitly addresses challenges in applying nanofluids for renewable energy, bridging the gap between nanotechnology and renewable energy generation. While nanoparticle applications hold promise for industries, challenges must be addressed for their full integration into industrial processes. Currently, nanofluid use in wind and hydropower energy is limited, but research potential exists for lubricating agent applications and energy recovery. • Review on the application of nanotechnology in renewable energy. • Role of nanoparticles in energy production from biomass to bioenergy. • Contribution of nanotechnology in carbon capture. • Challenges in applications of nanofluids in renewable energy. [ABSTRACT FROM AUTHOR]

Due to their rapid commercialisation, Photovoltaic (PV) systems are considered the foundation of present and future renewable energy. Nonetheless, the full potential of this technology has yet to be realised because of several challenges. Consequently, effective solutions are critical for achieving high solar PV performance. This work aims to consolidate and provide a unique global review of pioneering recent studies on the most influential factors affecting solar PV performance. Four driven parameters are emphasised: dust/soil, tilt angle, temperature, and humidity. Regional, national and international experiments performed indoor, outdoor and at the laboratory, real-scale studies and numerical simulation dealing with PV performance challenges and potential routes for improvement and optimisation are reported. The review included studies from across the world, including the Middle East, Africa, the Asia Pacific, America and Europe. The figures and detailed tables with pertinent information on the key subject are provided. The studies suggest that the dust can reduce PV efficiency by up to 24 %. Adjusting PV module alignment up to five times a year can enhance energy yield by 3.63 %. The efficiency drops by 0.05 %/°C, with the temperature increase from 25 °C to 45 °C causing an efficiency drop of up to 20.22 %. This paper provides a comprehensive analysis of the thermal management, economic implications, environmental impact, and disposal concerns associated with end-of-life PV modules, highlighting the need for effective regulations to address emerging challenges. Finally, this work can be used as a pertinent guide for communities working in the field of solar PV involving researchers, industrialists and policymakers in the design, sizing, application and commercialisation of high-performance PV technologies and systems. • Dust accumulation lowers the performance efficiency of the photovoltaic (PV) module by up to 40 %. • The power and efficiency of the PV module are reduced by 0.5 % and 0.05 % for every 1 °C rise in ambient temperature. • The optimum tilt angle of the module is determined by mathematical analysis and empirical correlations. • The maximum output of the PV module declined by 34.22 % for the increase in relative humidity by 50.15 %. • Degradation of the PV modules is expedited up to 23 times in highly humid conditions. [ABSTRACT FROM AUTHOR]

Sweden has experienced two decades of wind power expansion and enters a broad diffusion phase. In this study the aim is to deepen the knowledge of the municipal role in this phase in relation to national wind power policy. Local public officials and politicians was interviewed in fourteen Swedish municipalities. The results show that municipal representatives experience great uncertainty about the responsibilities and incentives they have in the energy transition – responsibilities that are difficult to interpret but also difficult to realize in practice. In conclusion, unclear State policy, increased social resistance, lacking municipal capabilities, and a market-driven planning regime adds a burden of incongruous responsibility on municipalities, which risks enforcing uncertainties in the transition of the national energy system. The study brings socio-technical insight to the global expansion of renewable energy within decentralized political systems. • Municipal operationalization of Swedish wind power strategy is studied. • Wind power planning regime presents incongruous responsibilities for municipalities. • Wind power development in high-demand Swedish regions for fossil-free energy is hindered. [ABSTRACT FROM AUTHOR]

As the mandatory scope of zero-energy building certification has expanded, the integration of renewable energy systems into building designs and energy operations has significantly increased. The long-term maintenance of these systems is crucial for sustaining zero-energy goals. The primary key to maintaining renewable energy systems is to assess quantitative performance factors, such as degradation and malfunction. This study presents a comprehensive evaluation of the long-term power performance of a large-scale vertical building-integrated photovoltaic system, which has been monitored over 9 years (2012–2020). The system, comprising 22 arrays with a total installed capacity of 142.654 kWp, was analyzed to derive quantitative performance indicators that highlight the importance of continuous maintenance. The photovoltaic system's arrays were investigated to separate them into analysis groups, and simulation-based analysis was carried out for the detailed assessments. The findings revealed that 19 of 22 arrays were operating normally, while three experienced malfunctions. In 2020, a 19.12 % performance degradation was observed in normally operating arrays compared to 2012. Post-malfunction, the affected arrays performed at approximately half the efficiency of the normal arrays. Despite theses issues, inverter efficiency remained stable across all arrays. However, a noticeable decline in array efficiency indicated performance degradation due to specific array issues. When compared to simulation-based theoretical performance, in 2020, the malfunctioned arrays exhibited nearly triple the performance degradation of the normally operating arrays. These results underscore the critical role of quantitative performance indicators in maintenance strategies and demonstrate how inadequate maintenance can lead to substantial power generation losses. [Display omitted] • Zero-energy building certification promotes application of renewable energy system. • Compared to application, attention to performance maintenance is lack. • This study emphasizes importance of maintenance for renewable energy system. • Performance of building-integrated photovoltaic system is assessed over nine years. • Performance is assessed based on International Electrotechnical Commission 61724-1. [ABSTRACT FROM AUTHOR]

A perfect combination of weather and a power system backed by battery-based energy storage enabled Ireland to break a renewable penetration record in February 2022, with 96 % of electricity demand covered by wind generation at its peak. In high renewable energy penetration scenarios seen worldwide, ensuring the resilience of power systems against major events has received increased attention. Supplementing traditional generation units with renewables and distributed energy resources (DER) in the energy mix to meet the load demand and net-zero emission goals has affected power system inertia, black-start readiness, service restoration, and operations. Maintaining adequate resources to retain black-start readiness in anticipation of widespread outages is becoming challenging. This study reviews the technical aspect of a 100 % inverter-based resources (IBR) based distributed restart zone (DRZ) to assist black-start. It investigates the feasibility of using a set of IBR control schemes to help restart a non-black start combined cycle unit by aggregated energy storage system and PV via transmission lines. Through assistance from power system operators, common operation practices are incorporated and simulated in a black start cranking path case study. Simulation results are reported and compared against the traditional practices based on hydropower. The results show that the IBR could supplement the traditional black-start resources. The functional requirements identified in this study would be useful for developing GFL and GFM inverter controls in the industry to enable black-start ancillary service by IBR. [Display omitted] • Shows how distributed renewables can reboot a power system post-blackout. • Proposed restart zone complements traditional methods, boosting grid resilience. • Simulations on a real power system prove distributed restart zones aid black-start. [ABSTRACT FROM AUTHOR]

The transition to renewable energy sources is crucial for combating climate change and enhancing energy security. However, along with well-acknowledged benefits, the energy transition may impose overlooked and unintentional risks to sustainability, stemming from patterns of trade between countries. The buildup of solar and wind energy capacity requires critical metals and equipment that are often imported, while too ambitious renewable energy and climate policies may lead to the offshoring of energy- and carbon-intensive industries, resulting in carbon leakage. This study uses principal component and cluster analyses to estimate indicators of trade-related energy security and carbon dioxide emissions embedded in trade of the sixty-four countries. The analysis indicates that wealthier countries, particularly those that are not energy self-sufficient, are more likely to utilize solar and wind energy. Solar and wind energy use is also associated with higher imports of embedded energy and emissions, as well as imports of metals and equipment required for renewable energy production. In contrast, energy-self-sufficient countries, being net exporters of both energy and energy embedded in products, barely use solar and wind for electricity generation and hardly import metals or low-carbon technologies. This study highlights the need to account for possible cross-border dependencies and displaced emissions, which may result from higher reliance on distributed renewable energy sources. [Display omitted] • The energy transition faces sustainability challenges due to cross-border trading. • Principal component and cluster analyses applied to analyze country-level data. • Renewable energy is linked to reliance on imported emissions and embedded energy. • Renewables may elevate dependence on imported metals and low-carbon equipment. • The World Energy Trilemma Index should account for cross-border interdependencies. [ABSTRACT FROM AUTHOR]

To accelerate the transition towards an energy system based on renewable energy sources (RES), governments set targets for RES shares in their energy mixes. Renewable energy also plays a major role in decarbonization strategies of private organizations. Electricity from RES is claimed via the acquisition of market-based Energy Attribute Certificates, such as Guarantees of Origin (GOs). GOs can be traded within the European residual mix area. Interest in GOs is lower in countries with high RES shares, leading to a trade imbalance. In 2020, Iceland and Norway had a GO trade deficit that corresponded to 74.2 % and 62.4 %, respectively, of their gross final electricity production from RES. This study evaluates the non-dependence of Europe's RES targets and the GO system by including GO trade in the RES share calculations. Overall, 11 countries do not reach their 2020 RES targets for the electricity sector due to the inclusion of GO trade. Their total GO trade deficit amounts to 212 TWh, equivalent to 31 % of all issued GOs from RES. Limiting international GO trade to ensure that each country still achieves its RES-E targets is one option to harmonize governmental and corporate RES and decarbonization targets. Other options include the complete prohibition of international GO trade and a GO trade limitation to actual physical electricity transmission. Further aligning physical and virtual electricity consumption could strengthen the energy transition contribution of energy attribute certificate systems, such as the GO system. [Display omitted] • Countries with high renewable electricity shares often export Guarantees of Origins (GOs). • 11 European countries would miss their 2020 renewable electricity targets due to GO trade. • 2020 GO trade deficit of countries missing their targets adds up to 212 TWh • Governmental renewable energy targets and the GO system require harmonization. [ABSTRACT FROM AUTHOR]

Natural hydro environments such as rivers and ocean currents provide abundant and essentially free sources of kinetic energy. Although significant research has been devoted to harnessing this power through traditional turbine systems, there are also studies on the novel use of flow-induced vibration of a bluff body. The large oscillations of an elliptical cylinder resulting from the newly-discovered hyper branch have raised interesting questions about its potential as a source of effective renewable energy. This study investigates the power extraction characteristics of the hyper branch over a range of flow velocities. A factor-of-ten increase in the maximum time-mean power coefficient relative to an established flow-induced vibration system — the vortex induced vibration for aquatic clean energy converter is demonstrated. This suggests the possibility of a new and effective strategy to utilise flow-induced vibrations for energy generation and could help drive the commercial implementation and uptake of oscillating energy converters. [Display omitted] • Thin elliptical geometry is inherently aerodynamically unstable. • Elastically mounted thin elliptical cylinder yields large crossflow oscillations. • Electromagnetic damper attached to cylinder is used to simulate generator loads. • Elliptical cylinder yielded a maximum power coefficient of 3.31. • Factor-of-ten improvement in power coefficient compared to other similar devices. [ABSTRACT FROM AUTHOR]

Decarbonising the global energy system involves several critical aspects, such as enhancing energy efficiency, expanding electrification, adopting alternative fuels, and leveraging hydrogen, among other strategies. Cold and cryogenic energy have substantial potential sources, extending beyond liquefied natural gas, as the demand for several alternative fuels and substances continues to grow. This study explores various techniques for harnessing cold energy to generate power, ranging from simple to complex technologies. It conducts a comparative analysis of promising technologies suitable for converting cold and cryogenic energy into power. Furthermore, it provides a detailed performance comparison for each technology and outlines prospects for future development. In the end, the study discusses the potential direction of further research and underscores the increasing significance of integrating cold and cryogenic energy into existing business models and value chains, not only as a means of transportation but also as a source of power generation. Harnessing cold and cryogenic energy as a seasonal Carnot battery presents a compelling and innovative solution. This advanced system offers significant potential, especially when integrated with variable renewable energy sources or waste heat, providing a promising option for enhancing energy efficiency and sustainability. [Display omitted] • Several alternative fuels and substances in large industries are discussed. • Several promising thermodynamic cycles and thermoelectric have been reported. • The performance of the selected cold energy-to-power conversion is compared. • The challenges and future trends of cold energy-to-power conversion are discussed. [ABSTRACT FROM AUTHOR]

The growing expansion of distribution systems propelled by high penetration of renewable energy sources, growth of electric vehicles, the integration of energy storage systems, and the implementation of demand-side management strategies have introduced uncertainties related to generation fluctuations, and consumption patterns. These uncertainties are to be modeled precisely and effectively to achieve flawless embedding of the distributed energy resources into the distribution grid. This paper begins by highlighting the growing importance of distributed energy resources in active distribution network planning and then provides a comprehensive overview for methods used in the literature to characterize uncertain parameters, specifically through probability distributions, distributionally robust representations, and robust uncertainty sets. The study principally aims to critically analyze the prevailing techniques for modeling and optimization of active distribution planning problems with high penetration of distributed energy resources under growing uncertainties in physical space, such as intermittency in renewable energy production, demand variation, network topology changes, variability in electric vehicle charging load, and customer attitude towards demand response. Various methodologies, including probabilistic methods, possibilistic methods, stochastic optimization, robust optimization, information gap decision theory, and hybrid approaches, are thoroughly assessed and compared. This comprehensive and comparative assessment aids researchers in selecting the most appropriate uncertainty modeling technique in accordance with the characteristics of uncertain variables and the specific planning problem being addressed. Furthermore this study also examines the implications of cyber space uncertainties in active distribution network planning. [Display omitted] • The conceptual framework and potential areas of analysis in active distribution network planning are presented. • Thorough examination of uncertainty quantification and uncertainty modeling techniques are conducted. • Joint implications of cyber space and physical space uncertainties on active distribution planning problems are explored. [ABSTRACT FROM AUTHOR]

South Africa's transport sector is a major contributor to carbon emissions due to its reliance on liquid fossil fuels such as diesel and petrol. In a bid to decarbonize the transport sector, South African government is committed to developing its green economy through the use of clean and renewable energy sources. Biogas, as a renewable energy source, can be derived from food waste (FW); upgraded to bio-compressed natural gas (bio-CNG) and applied as a vehicle fuel. This study assesses the economic feasibility of upgrading biogas to bio-CNG as a transportation fuel in South African provinces. The FW generation was determined using a mixture of population and income models while the biogas generation is modelled using modified Bushwell's equation. The economic analysis was premised on four economic metrics such as net present value (NPV), payback period (PBP), internal rate of return (IRR), and levelized cost of bio-CNG (LCO-bio-CNG). Some important findings indicate that an average of 6.6717 million tons/year of FW is generated in South African provinces producing 11.7111 million Nm3 of bio-CNG which is capable of filling about 1.2 million 10 m3 compressed gas cylinders. Economically, the project is profitable with positive NPV in all provinces, less than 2 years PBP, minimal LCO-bio-CNG (0.0551–0.0807 USD/m3) as well as remarkable IRR (31.15–36.08 %). Sensitivity analysis was also conducted to determine the influence of some critical parameters on the general performance of the project. This study provides valuable information for optimal investment in bio-CNG for public transportation. [Display omitted] • The bio-CNG generation potential from food waste for each province is estimated. • The economic assessment for the bio-CNG implementation is evaluated. • The volume of bio-CNG can fill about 1.2 million 10 m3 of compressed gas cylinders. • The bio-CNG project is found to be economically viable in all South African provinces. • Policy implications for the optimal investment in bio-CNG are suggested. [ABSTRACT FROM AUTHOR]

The transition to renewable energy sources, particularly wind turbines and solar photovoltaics, is critical to achieving a climate-neutral European Union. However, challenges in deployment arise related to land conflicts, aesthetics, regulatory barriers and others. While studies have indicated optimal locations, their actual location and associated location determinants remain unknown. This study addresses this gap, with contributions in three key areas. Firstly, it presents the most recent and coherent spatial dataset of onshore wind turbines (118,238) and industrial solar photovoltaics (670 km2) in the European Union, extracted from Open Street Map. The results present an 8.5-fold and 2.5-fold increase in onshore wind turbines and solar photovoltaics, respectively, compared to similar results from 2020. Secondly, the study provides two models to understand the significance, associated relationship, and strength of a wide range of variables as location determinants. It identifies 16 significant predictors for onshore wind turbines, and 13 for solar PV, uncovering previously unconsidered predictors in optimal placement studies. A 50-fold cross-validation concluded the robustness of both models, allowing for the development of probability maps that illustrate the future expansion potential in the European Union. The regions with the highest wind turbine potential include Denmark, Ireland, the Netherlands, Belgium, northern Germany and France. For solar PV, areas with significant potential are found in the Netherlands, Germany, flat regions in Italy, southern and central Spain, Poland, the Czech Republic, and Hungary. [Display omitted] • In the EU, 118,238 onshore wind turbines and 670 km2 of solar PV were identified. • Two separate models explain the occurrence of onshore wind turbines and solar PV. • Probability maps show where future renewable energy installations can be expected. [ABSTRACT FROM AUTHOR]

Seawater source heat pumps (SWSHP) offer promising renewable energy solutions for coastal cities, aligning with China's carbon neutrality goals. This comprehensive review synthesizes state-of-the-art SWSHP technology, identifies key research gaps, and proposes future research directions. SWSHP systems are classified into open and closed loops, with analysis of seawater intake modes and heat exchanger types. Performance evaluation indexes for energy, economic, and environmental aspects are summarized. The review highlights SWSHP's potential in district heating and mariculture, emphasizing the importance of considering seawater temperature, tides, and district characteristics for implementation. Key challenges identified include corrosion issues, thermal pollution, suboptimal complementary energy design, and techno-economic barriers. An interdisciplinary perspective offers a holistic view of SWSHP systems and their impacts. The review contributes by identifying seven critical research areas: large-scale SWSHP systems, multi-energy integration, energy storage integration, mariculture-specific applications, comprehensive evaluation frameworks, marine ecological impact assessments, and cutting-edge technology development. This work provides valuable insights for policy decisions and critical analysis of current limitations, aiming to advance SWSHP technology and promote sustainable implementation in coastal regions. By addressing these research gaps and focusing on proposed directions, this review guides future research and development in the renewable energy sector, supporting the transition towards sustainable energy utilization and climate change mitigation. [Display omitted] • SWSHP: a promising renewable energy technology for China's coastal regions. • Various SWSHP types classified and analyzed for their unique characteristics. • Energy, economic, and environmental evaluation methods for SWSHP summarized. • SWSHP shows great potential in district heating and mariculture in coastal cities. • Key challenges identified and recommendations made for reliable SWSHP systems. [ABSTRACT FROM AUTHOR]

Solar power has gained popularity as an alternative to tackling global energy and environmental issues. However, concerns about the unpredictable nature of renewable energy sources, irregular behavior, and partial shading of solar panels hinder photovoltaic (PV) system stability and efficiency. Utilization of a solar charge controller (SCC) with pulse width modulation (PWM) and maximum power point tracking (MPPT) functionality is imperative to enhance the effectiveness and reliability of PV systems. Fluctuating external conditions make MPPT challenging, particularly under non-ideal operating conditions such as partial shading or temperature variations. Advanced MPPT control methods have been proposed to address these challenges, outperforming conventional algorithms. This study provides a comprehensive review and analysis of the control strategies employed in PWM and MPPT for PV systems. Each MPPT technique has pros and cons, but a streamlined approach considers cost, accuracy, complexity, speed, analog/digital, and efficiency. The intent is to contribute to the widespread adoption of the MPPT technology and address the challenges associated with PV system implementation. Through diligent research efforts, MPPT systems improved efficiency in managing renewable power generation intricacies. Utilizing advancements in SCC with PWM and MPPT enhances energy harvest, increases system reliability, prolongs battery life, and improves solar energy system performance. The fundamental discoveries are condensed in advancing progressively resilient controllers for enhanced efficiency, reliability, stability, protection, and nations. This work aids the transition to clean energy systems and provides a foundation for selecting the most effective MPPT controller for future research direction toward sustainable development. [Display omitted] • Advanced MPPT techniques boost PV system efficiency and performance. • Technology constraints are analyzed to enhance controller performance. • Innovative SCC designs with built-in PWM and MPPT enhance PV system performance. • This review improves the accuracy, effectiveness, and durability of controllers. [ABSTRACT FROM AUTHOR]

Calcium-looping energy storage technology presents a promising potential to address the instability issues associated with the renewable energy sources (e.g. solar power). In this work, a fluidized bed is comprehensively analyzed as an energy release device. A multiscale method is proposed to investigate the mechanisms involved in the reaction and heat release during the exothermic carbonation process, spanning from the grain scale to the reactor scale. The accuracy of the model in terms of reaction kinetics and heat transfer is rigorously validated against experimental results. It is revealed that the carbonation reaction exhibits three distinct stages within 40 s, characterized by changes in reaction rate: the rapid reaction stage, the transition stage, and the equilibrium stage. The rapid reaction stage experiences significant fluctuations in the reaction rate due to factors such as gas-solid temperature distribution, reactant gas concentration distribution, and the phenomenon of gas back-mixing. Observations in the reactor show distinct zones, including the bubble zone, dense phase zone, splash zone, and freeboard zone, where bubbles exhibit a cap-shaped morphology. The reaction rate near the bubbles is approximately 10 times higher than that in the dense phase zone, highlighting the critical role of dense and small bubbles in facilitating mass transfer during carbonation. Additionally, grain size significantly influences the carbonation process, with smaller grain sizes promoting the reaction. This study has established a fundamental mechanism of heat release during the carbonation reaction, providing a solid foundation for future investigations into the carbonation-calcination looping process. • A model ranging from grain to reactor scale is proposed to study carbonation process. • The chemical reaction kinetics based on the grain model is developed for CFD process. • The process is investigated from micro-reaction and macro-concentration distribution. • The influence of the particle-bubble dynamics on the reaction process is analyzed. [ABSTRACT FROM AUTHOR]

Promoting renewable energy sources and effective storage, conversion, and transportation technologies to address non-renewable energy supply and environmental issues is a need of the time. The unique features, including its environmentally benign nature, high mass energy density, and known as a clean energy carrier, make hydrogen energy an appealing substitute for fossil fuels in both mobile and fixed applications. Hydrogen has become the most significant source of energy as the need for energy increases. It is a crucial strategy for preventing the increase in pollutants and global temperature. Despite its advantages, the high flammability of H 2 requires adequate safety measurements at the points of storage, production and application. A safe, cost-efficient, compact and light hydrogen storage medium is essential for the hydrogen economy. Highly pressured gaseous hydrogen and liquid hydrogen storage systems are the conventional hydrogen storage systems. Solid-state storage systems have received interest because they can safely, compactly, and irreversibly store large amounts of hydrogen. This overview presents effective methods for hydrogen synthesis, storage, safe transportation, and application.Technologies for producing hydrogen are already commercially accessible, and some of them are still in development. Therefore, there is a desire to reduce the environmental impact of greenhouse gases and other pollutants that are increasing on a global scale. Even though there have been significant advancements in hydrogen technology, but more sustainable research efforts are still required to develop the techniques. [Display omitted] • A detailed review on hydrogen production methods including renewable and non-renewable. • Hydrogen storage strategies and infrastructure. • Advancements in the transportation of hydrogen. • An overview of the different industrial applications of hydrogen. • Effect of hydrogen on worldwide environmental issues. [ABSTRACT FROM AUTHOR]

Renewable energy needs to be expanded because it is important for sustainble development. There is the need to study the importance of factors that drive renewable energy. This study mainly focuses on assessing the impact of green technology (GTI), research and development (RDT), and the digital economy (DEC) on renewable energy innovation (RENT) in BRICS countries. The study used FMOLS and DOLS as the main econometric methods to determine the long-run empirical estimates from 2000 to 2022. The research is expected to provide important implications to policy planners as to how they should expand the scope of renewable energy. The findings of the study are as follows: (1) Green technology positively influenced RENT in BRICS countries. (2) The study documented a positive relationship between RDT and RENT. (3) The DOLS analysis shows that the DEC fosters renewable energy companies. (4) The findings also indicate a negative correlation between DEC and RENT in BRICS countries. It is recommended that policymakers in BRICS economies formulate and execute policies that promote green technology advancement, research, and development initiatives, and foster digital economy integration to spur renewable energy innovation. [Display omitted] • Impact of green technology, research and development on renewable energy. • Impact of the digital economy on renewable energy innovations. • BRICS countries are chosen. • Digital economy fosters renewable energy innovation. [ABSTRACT FROM AUTHOR]

Limestone calcination produces calcium oxide (or lime), that forms the basis for the manufacturing of many critical engineering materials such as cement and iron-and-steel. Limestone calcination—an endothermic reaction—is regarded as one of the most energy-and-CO 2 intensive industrial chemical reactions, and is facilitated by fossil fuels, since the high temperature requirement (∼900 °C) renders it less conducive to electrification through renewable energy sources. In this study, a novel, low-temperature (∼450 °C) pathway for ultrafast calcination of limestone using combustion synthesis or self-propagating high-temperature synthesis (SHS) is developed. SHS leverages exothermic heat from the combustion of lignin or biomass—as low-carbon fuels—mixed with limestone. Pelletized samples consisting of different limestone-fuel ratios are subjected to SHS reactions in a furnace maintained at 350 °C or 450 °C, and the degree of limestone-to-lime conversion is determined using thermogravimetry. The type and content of fuel and the kinetics of combustion influence the: (a) temperature evolution in the sample; (b) time to attain peak temperature and the total SHS time (<15 min); (c) expansion of the pellet; and (d) rate and extent of reactant-to-product conversion. The use of lignin alone, or an equal mix of lignin and biomass as fuel, achieves a limestone-to-lime conversion exceeding 90 %, contingent on processing conditions like pellet size and airflow rate. It is thus shown that SHS—which (i) uses less than half the energy, (ii) releases 25–30 % lower CO 2 emissions, and (iii) is > 4X faster than a conventional thermal process—is a sustainable and viable approach for limestone calcination. • Ultrafast SHS method implemented for the first time in the calcination of limestone. • Biofuels mixed with limestone, subjected to temperatures much lower than limestone's calcination temperature. • Elucidation of the influence of critical parameters on calcination kinetics and product formation. • Significant reductions in carbon emissions and energy consumption associated with calcination. [ABSTRACT FROM AUTHOR]

Most of the energy demand is currently supplied from fossil fuels, which leads to the accumulation of greenhouse gases and air pollution. A sustainable future can be created globally through the efficient use of renewable energy sources. These sources include wind, solar, geothermal, biomass, and more. Geothermal energy can meet the energy needs of the future as a clean and reliable source and stands out due to certain distinctive features among renewable energy sources. Unlike other renewable energy sources, geothermal energy is not dependent on time or weather, making it a reliable and continuous energy supply. Additionally, it has a lower environmental impact. This review examines the development of geothermal energy systems and their integration into smart technologies, highlighting the potential of geothermal energy for smart energy systems. The focus is on integrating smart systems into geothermal-based setups to enhance efficiency and analyze the state-of-the-art technologies of such systems. Geothermal-based systems can be classified as single generation, co-generation, multigeneration, smart energy systems, and energy hubs. Consequent to examining systems, it has been concluded that geothermal systems have a huge potential, but unfortunately, not all of them are used due to some difficulties. Its development will occur faster, and its share in the renewable energy sector will grow with smart system integration. [Display omitted] • Detailed examination of geothermal based energy systems. • Opportunities and challenges of geothermal energy. • Geothermal energy is more reliable than other renewable energies. • The potential of smart systems to integrate into geothermal-based systems. • Green hydrogen production with geothermal energy. [ABSTRACT FROM AUTHOR]

The global demand for sustainable energy sources drives interest in flow energy harvesting for renewable energy generation. Understanding the impact of boundary region size is crucial to create practical and autonomous devices. This study investigates how changing the distance between wall boundaries (y∗) affects the performance of a piezoelectric-based energy harvester that converts aeroelastic motion into electrical energy. The research focuses on the interaction of a piezoelectric flag with fluid flow downstream of inverted C-shaped and circular cylinders placed in a uniform fluid flow. The dynamic behavior of the piezoelectric flag is influenced by the gaps between the cylinders and the flag (D x), as well as between the cylinders and the walls (D y), leading to fluctuations in the levels of harvested power. The arrangement of cylinders with specific dimensions (2.0 ≤ D x ≤ 3.0, D y = 4.65) consistently demonstrates the highest power output through continuous flag motion. The inverted C-shaped cylinder outperforms the circular cylinder, showing a 19 % increase in power output. Particle Image Velocimetry (PIV) experiments confirm these findings by showing improved wake dynamics alignment and energy efficiency. However, certain gap sizes lead to lower energy production due to boundary effects and inadequate wake flow coupling. This research provides valuable insights into the optimal design configuration for piezoelectric-based energy harvesters in fluid flow environments. • Effect of channel gap variation is studied experimentally on a piezoelectric flexible flag. • Two bluff bodies and various distances between the flag and the walls are examined. • The inverted C-shape cylinder increases disturbance region and energy harvesting capabilities. • There is a specific channel gap that yields an exceptional increase in the power output. [ABSTRACT FROM AUTHOR]

Liquid air energy storage (LAES) has emerged as a promising solution for addressing challenges associated with energy storage, renewable energy integration, and grid stability. Despite current shortcomings, including low round-trip efficiency, poor economic performance, and limited engineering applications, LAES still demonstrates significant potential, particularly in short-term large-scale energy storage and renewable energy power integration, thanks to the high energy storage density, lack of geographical limitations, and minimal environmental impact. Previous review papers predominantly addressed advancements in thermodynamics and economics but overlooked key aspects such as dynamic performance and sustainability. Additionally, these review papers heavily emphasized system simulations, neglecting the research progress in experimental studies. Furthermore, the summaries of advancements in LAES subsystems were insufficient. This paper fills the gaps mentioned above and provides a comprehensive overview of LAES technology, covering its development history, comparison with other energy storage technologies, and research progress of LAES subsystems, standalone LAES systems, and hybrid LAES systems. Despite these achievements, key challenges remain, including high initial investment costs, complex technical requirements, and low operational efficiency, which collectively constitute barriers to the widespread adoption of LAES technology. This paper also identifies current research shortcomings and provides recommendations for future research directions. Further research and development of LAES technology are essential for alleviating fossil fuel shortages, environmental pollution, and excessive greenhouse gas emissions, and for realizing the full potential of LAES and its widespread application in the renewable energy utilization and energy storage sectors. [Display omitted] • Conduct a comprehensive review of LAES technology. • Review dynamic characteristics, ecological performance, and experimental studies. • Report advancements in LAES subsystems, basic LAES systems and hybrid LAES systems. • Identify current shortcomings and recommend future directions. [ABSTRACT FROM AUTHOR]

Rampant use of fossil fuels resulting in environmental pollution has necessitated the exploration of renewable energy sources. Sustainable development goal 7 stipulates the need for affordable, clean energy to meet human and industrial needs. Abundance of organic waste, in developing economies, makes methane from biogas a major source of renewable energy. The main limitation being that the raw biogas contains carbon dioxide, hydrogen sulfide and other unwanted gases, therefore it requires purification to remove non-methane components. However, existing biogas purification and upgrading systems are relatively expensive and require sophisticated technology and skills to operate them, hence they are unaffordable especially in many developing economies. Besides, these technologies are mainly applicable to large scale systems and are unsuitable for the small-scale systems mostly found in developing economies. This review critically evaluates the potential of low-cost biogas purification materials such as iron rich soils, activated carbon from solid waste, waste iron fillings, and biomass ash for use in household and small-scale biogas plants. These materials have demonstrated considerable performance achieving the following removal efficiencies; clay (90 %); iron-rich New Zealand Brown soil (93.8 %); commercial steel wool (95 %); and compost (80 %). This study proposes new ways to improve the performance of these materials through proper pretreatment of biomass ash to reduce moisture content, surface modification of activated carbon for improved acid gas uptake, integration of adsorbents to create synergy, regeneration and reuse of these adsorbents to promote sustainability. Low-cost materials demonstrate great promise towards achieving SDG 7 especially in developing economies. • Purification of biogas using low-cost materials has not been studied widely. • Iron rich soils, waste organic matter cane be applied for biogas purification. • Pretreatment and surface modification can improve performance of these materials. • Integration to create synergy, regeneration and reuse will ensure sustainability. • Green materials for biogas purification have great potential and are sustainable. [ABSTRACT FROM AUTHOR]

Geothermal energy is a renewable energy source that can contribute to a decarbonized European energy mix. Geothermal Organic Rankine Cycle (ORC) units can produce power from medium enthalpy hydrothermal resources that are commonly available in Europe. However, their techno-economic and environmental performance is greatly dependent on the site-specific geological conditions. This study proposes a two-step framework to optimize the design and investigate the Levelized Cost Of Electricity (LCOE), Global Warming Impact (GWI), and fifteen other environmental indicators of geothermal ORC units for various geological conditions. First, the LCOE and GWI of the system are calculated via integrated geo-technical, ORC process, techno-economic and life cycle analysis calculations. Second, artificial neural networks (ANN) are used to model for the system and genetic algorithms are used to optimize its design for multiple techno-economic and environmental objectives. It is shown that the techno-economic and environmental performance of the geothermal ORC are driven by the same factors. A higher geofluid temperature results into higher power production and lower LCOE and environmental impacts. Similarly, the LCOE and environmental impacts reduce for increasing reservoir permeability and thickness because the pumping capacity to extract the geofluid reduces. This study shows that geothermal ORCs can be a promising alternative for power production in Europe, though their techno-economic and environmental performance are strongly dependent on the local geological conditions. These conditions can also influence the optimal ORC design. This study also demonstrates the benefits of using ANNs for the optimization of geothermal ORC units. [Display omitted] • The geological conditions determine the design, LCOE, and GWI of the ORC. • The LCOE and GWI reduce with the reservoir temperature, permeability and thickness. • ANN can accurately model for the geothermal ORC and the reservoir response. • ANN facilitate the optimization of geothermal ORCs. [ABSTRACT FROM AUTHOR]

This work analyzes the volatility connectedness of the prices of ethanol and gasoline sold to consumers in fifteen Brazilian capitals. Our data cover the period from 2012 to 2022 and contains several different moments in the dynamics of domestic prices, such as changes in tax policy prices, the crises of covid-19, and the war in Ukraine. The results suggest that fuel prices in the capitals are connected. Gasoline prices substantially affect ethanol prices, indicating that fossil fuel is still stronger in price formation than fuel of renewable origin. The shocks are asymmetric. Price increases in one location lead to increases in others relatively quickly. Price reductions do not propagate at the same speed or intensity. [Display omitted] • Analysis of complex relationships between ethanol and gasoline markets in Brazil. • Analysis of a market that uses a renewable fuel coexisting with fossil fuels. • Fuel prices analysis under impact of changes in tax, covid-19 and war in Ukraine. • Gasoline prices substantially affect ethanol prices in Brazil. • Fuel price increases spread quickly, but reductions spread slowly and in disarray. [ABSTRACT FROM AUTHOR]

Under the global low-carbon target, hydrogen is essential to address uneven energy spatial distribution and seasonal energy imbalances. However, the issues of insufficient energy interaction between different links (e.g., production, storage, and application) of hydrogen in planning models hinder the full hydrogen exploitation. This study proposes the concept of a complete hydrogen energy chain covering the energy flows of all the links and optimizes the hydrogen chain-based energy system's bottom-up long-term investment strategy. It aims to facilitate the transfer of multiple energy flows across time and space for renewable energy efficient consumption. Firstly, a hydrogen chain-based fast clustering optimization method is proposed to deal with high-dimensional data to achieve a fast solution for large-scale long-term planning. Secondly, a high-resolution collaborative planning model of the multi-energy systems integrating the complete hydrogen energy chain is proposed, considering the renewable energy spatiotemporal distribution characteristics and annual hourly operation. Finally, this study thoroughly examines the optimal portfolio selection of different hydrogen technologies based on the differences in cost, flexibility, and efficiency. Taking Northeast China in 2050 as an example, the results show that: The proposed model reduces CO 2 emissions by 60 % with 30 % additional cost in Pareto analysis. At zero-carbon emissions, integrating the complete hydrogen energy chain reduces the renewable energy curtailment by 97.0 %. Meanwhile, the energy system prefers the electrolysis cells with the highest energy efficiency and the fuel cells with the fastest dynamic response. This study provides future energy system planning guidance for countries or regions to realize low-carbon targets. [Display omitted] • A complete hydrogen energy chain contributes to renewable energy consumption. • Propose a hydrogen chain-based fast clustering optimal method for long-term planning. • Electrolyzer capacity is closely linked to renewable energy geographical allocation. • Transportation and storage of hydrogen is key to future affordable energy systems. • SOEC and PEMFC are the preferred options for achieving zero-carbon emissions. [ABSTRACT FROM AUTHOR]

Dramatic increases in variable renewable energy require enhancing power system flexibility to ensure reliable electricity supply. Flexible hydropower can undertake the renewable and natural storage role with adequate strategic operations considering cross-timescale detailed water-energy dynamic coupling characteristics and water demands. Here this study develops an hourly-to-multiyear framework to investigate hydro-wind–solar complementarities across different complementary modes, applying it to China Southern Power Grid. Results indicate that potential synergies and portfolios across complementary modes are distinct in China Southern Power Grid. Furthermore, regional resources interconnections could enhance the spatiotemporal hydro-wind–solar synergies and mitigate the hydrological-related impacts on the complementary potential. By effectively harnessing the spatiotemporal complementarity of renewable energy sources, hydropower is expected to leverage its reservoir regulation capability and cascading joint management capability to integrate wind and solar resources at 1.5 times its own capacity. Our work contributes to a better understanding of the future planning grid expansion and operation of China Southern Power Grid. [Display omitted] • Introduce a hourly-to-multiyear framework to investigate hydro-wind–solar complementarity. • Identify the hydrological-robust hydro-wind-solar complementary mode. • Pooling regional resources could increase spatiotemporal complementarity of renewables. • Derive the strategic regional renewable electricity portfolios. [ABSTRACT FROM AUTHOR]

In recent years, the global expansion of solar photovoltaic power plants has seen rapid acceleration fueled by technological advancements, substantial cost reductions, and favorable regulatory reforms. Although pivotal to the transition towards sustainable energy sources, the integration of a large number of photovoltaic plants presents unique challenges for the system operator in ensuring grid stability and security. Therefore, it has become increasingly important for these plants to provide adequate grid support services and maintain voltage and frequency stability, similar to conventional generators. In this context, this paper critically analyses the diverse strategies and advanced trends for acquiring grid support services from solar photovoltaic power plants. The relevant procedures are garnered from the literature, which dates back to the earliest reported methods. The review encompasses the analysis of different applications related to active power control for frequency regulation, reactive power control for voltage regulation, and black-start support for system restoration. The paper also examines the existing challenges and delves into the opportunities to transform the interaction of photovoltaic power plants with electricity grids. As solar photovoltaic penetration increases, the role of these grid support services becomes ever more critical, requiring innovative solutions, conducive regulatory frameworks, and a thriving market structure to support the continuously evolving energy landscape. [Display omitted] • Analysis of advanced grid support strategies for integration of solar PV systems. • Critical review of active and reactive power controls in PV systems. • Scrutiny of challenges and innovations in PV-based frequency and voltage regulation. • Discussion on potential black start ancillary services from solar PV systems. • Prospective solutions for enhanced PV-grid interaction amid growing solar adoption. [ABSTRACT FROM AUTHOR]

Participatory practices and social innovations are recognised as important for sustainable renewable energy projects. However, information on the significance of diverse participatory practices and social innovations for advancing inclusive and sustainable wind energy developments remains limited. To address this gap, this study aims to understand how diverse participatory practices in wind energy developments across the globe influence energy justice differently. It does so, by analysing how a fairer participation of communities is interconnected to the models of participation while investigating how participatory practices interrelate with social innovations. Drawing on the 'ecologies of participation' approach, the work compiles a dataset of 312 case studies of collective participatory practices in wind energy projects, of which 209 are classified as social innovation projects. Findings indicate that not all participatory practices and social innovations are equal in ensuring just processes in wind energy governance. This requires careful consideration of different aspects of participation (e.g., opportunities provided, continuity of the process) and adherence to principles of justice in wind energy governance (e.g., inclusivity, capacity to influence, transparency). Conclusions highlight that fairer participation practices are interconnected to both the models of participation and to the wider spaces of participation in which they are embedded. [Display omitted] • Original dataset of 312 cases of participation in wind energy. • Participatory practices are multifaceted and relational. • Opportunities for participating increase with more inclusive participation models. • Most participatory practices lack in-depth engagement of local communities. • Social innovation initiatives contribute to inclusive participation in wind energy. [ABSTRACT FROM AUTHOR]

Black start is the restoration of an electrical power system following a total or partial system shutdown. A loss of supply of this magnitude is a most unusual event but must be anticipated as it has significant societal and economic consequences. Many countries are moving towards a low-carbon electricity system, and the fossil generators that currently provide black start capability are being replaced by renewable energy generators, many of which are individually of limited capacity. This reduction in the number of large conventional generators is leading to a need to reconsider black start practices and to question whether restoration of a de-energized network through a skeleton transmission system should be replaced by establishing multiple power islands each with smaller generating units. Using academic studies and the results of two innovation projects recently completed in Great Britain (GB), this study reviews the established power system black start practices and the participation of renewable energy resources in the black start. After traditional black start practices are reviewed, the challenges and solutions for using renewable energy sources and distributed energy resources to support black start are investigated. Restoration control and planning strategies in academic studies are discussed. Then the evolving power system black start practices in GB are discussed, and the methodologies and findings of two innovative black start projects in GB are reviewed. [Display omitted] • Roles of renewables and distributed energy resources in black start are assessed. • Control of renewables or distributed energy resources in black start is analyzed. • Restoration planning with renewables or distributed energy resources is discussed. • The methodologies and findings of black start projects in GB are reviewed. [ABSTRACT FROM AUTHOR]

The multi-terminal high voltage direct current (MTDC) transmission network using voltage source converters (VSC) has emerged as a significant method for integrating renewable energy sources into the conventional alternating current (AC) system. In such a system, unequal active power allocation and fluctuation in DC voltage causes stability problems. The main technical obstacle hindering the progress of MTDC systems is the controlling of DC voltage within the permissible operational range. Herein, the paper aims to review various control methods for MTDC systems that considerably improve system performance by regulating the balanced active power and keeping the DC voltage stable. Although numerous MTDC review papers are available, they frequently focus on specific aspects related to the protection and control of system components. Conversely, this paper provides a comprehensive, up to date overview, assessment and analysis of DC voltage and active power performance in the MTDC based on the voltage and power characteristics. This study examines the technical performance of control schemes and investigates the effectiveness of these control methods under both normal conditions and significant power instabilities. Further, the performance of control techniques is summarized and compared based on various parameters, including steady state and transient conditions, the requirement of communication link and expandability, stability, and flexibility in MTDC. The findings indicate that the droop control-based methods exhibit superior performance. Finally, the future developments in MTDC are discussed. [Display omitted] • Analyzed the impact of active power and DC voltage on control performance in MTDC. • Described the control schemes used in MTDC based voltage and power characteristics. • Compared the control effectiveness under the steady state and transient conditions. • Droop control-based techniques have better control performance. [ABSTRACT FROM AUTHOR]

This paper takes a smart energy system's approach to the analysis of the need for energy storage and balancing in a future climate-neutral society and thus supports and advances the United Nations' sustainable development goals, in particular SDG 7 (Affordable and clean energy). The study qualifies and quantifies that the best solutions to the transition can only be found by taking a cross-sectoral holistic approach – also known as a smart energy system's approach. Optimal investments in storage and resulting levels of curtailment are identified based on five smart energy system integration levels (SESIL), progressing from a sole electricity sector focus to a fully integrated system of electricity, heating, cooling, industry, transport, and materials. The study finds and quantifies that the overall least-cost solution is only identified in a fully integrated smart energy system, with affordable types of energy storage and little curtailment which cannot be found in a sole electricity sector approach. Furthermore, the study shows and quantifies that with the aim of a climate-neutral society, it becomes essential to take a holistic smart energy system's approach to identify least-cost storage and energy balancing solutions, and suggests a tool and a method to identify such solutions. Fig. 1: Energy and Carbon Flows of the "Smart Energy Denmark 2024" scenario. (1) Sources of energy and carbon from renewable energy and sustainable use of biomass are converted into (2) Energy and Carbon Carriers in the form of electricity, district energy and biofuels to cover (3) End Use of energy in all sectors as well as carbon for CCS and biochar to compensate other greenhouse gas-emitting sectors and CCU for the production of green fuels. CCU is thus both an end use and a source. [Display omitted] • Simulations of carbon-neutral energy system configurations. • Five smart energy system integration levels are defined and analysed. • Storage and flexibility requirements at different levels of cross-sector integration. • A full sector-integrated approach is required to identify optimal solutions. [ABSTRACT FROM AUTHOR]

In the context of a highly uncertain global economic environment, exploring the relationship between supply chain allocation and total factor productivity (TFP) of renewable energy enterprises not only helps to optimize the support policy for renewable energy but also ensures the resilience of supply chain and promotes the micro foundation of energy transition. Based on the data of listed renewable energy enterprises in China from 2010 to 2022, this research systematically verifies the impact of the relative choice of diversification and concentration on the TFP of renewable energy enterprises from the perspective of the enterprise supply chain. The results show that: (1) Supply chain diversification can improve the TFP of renewable energy enterprises, but the impact of supply chain configuration on small and medium-sized enterprises is more significant. (2) Through mechanism analysis, it is revealed that supply chain diversification can improve the TFP of renewable energy enterprises mainly through three channels: improving the asset turnover, reducing the performance fluctuation, improving the knowledge absorptive capacity. (3) Compared with other industries, it is found that renewable energy enterprises are more vulnerable to the impact of climate change, which is the main reason for the heterogeneous impact of renewable energy supply chain configuration. Based on the above research, this study proposes policy suggestions to optimize the supply chain of renewable energy enterprises, so that renewable energy enterprises can reduce the potential fluctuation risk, by taking into account the cost reduction and efficiency increase. [Display omitted] • The diversification of supply chains in the renewable energy sector leads to an enhancement in TFP. • Diversification works through asset turnover, performance fluctuation and knowledge absorptive capacity. • Renewable energy enterprises are more vulnerable to the impact of supply chain. [ABSTRACT FROM AUTHOR]

The increased participation of variable renewable energy sources (VREs) in electrical matrices worldwide is essential for achieving several United Nations Sustainable Development Goals (SDGs), such as SDGs 7 (Affordable and Clean Energy) and 13 (Climate Action). However, it brings several challenges to the planning and operation of power systems, mainly due to the intermittency of VREs. In this context, the complementary effects between different intermittent resources have garnered growing attention in the literature since such properties offer a collective capability to capture the stochastic nature of intermittent power generation when simulating scenarios. This work proposes a stochastic simulation model of renewable energy generation that explores several complementary effects between wind and photovoltaic resources in different Brazilian locations. The approach considers calculating energy generation states to simultaneously represent the generation of multiple renewable sources and using probability transition matrices based on historical data. The synthetic time series are subsequently assessed using statistical methods that indicate good adherence of the generated scenarios to most stylized facts of the historical series. [Display omitted] • A methodology to simulate stochastic scenarios for renewable energy sources. • The proposal aims to capture the complementarity between energy sources. • Multidimensional energy production states represent multiple sources. • Temporal and spatial levels of complementarity are studied. • Main joint characteristics of renewable energies are satisfactorily replicated. [ABSTRACT FROM AUTHOR]

Understanding the efficiency dynamics of green innovations is essential for advancing sustainable economic systems. This study evaluates the efficiency of forty-two countries in producing and utilizing green innovations for clean energy production and in achieving sustainable development goals from 2000 to 2020. Employing a network bias-corrected data envelopment analysis (DEA) and Malmquist productivity analysis, this study explores the adoption of green technology and its effects on economic and environmental efficiency. Findings reveal limited progress in clean energy efficiency across most countries, indicating suboptimal use of green innovations for the goals of affordable and clean energy and climate action). The results show that the efficiency pattern of green innovations follows a U-shaped curve, with initial inefficiencies followed by long-term gains. South American nations and the European Union demonstrate strong performance in integrating green technologies. However, green innovations alone appear insufficient; supportive policies, such as green taxes on emissions and renewable energy initiatives, are crucial for enhancing impact and achieving environmental sustainability. [Display omitted] • The study evaluates countries' green innovation efficiency for renewable energy and SDGs. • Many countries show low efficiency in environmental and renewable energy innovations for SDGs. • Green innovation efficiency shows a U curve pattern. • South America and the EU excel in green innovations for clean energy production. [ABSTRACT FROM AUTHOR]

Small hydropower is a crucial renewable energy source in China and plays a significant role in achieving social, economic, and ecological sustainable development goals. However, rapid Small hydropower development has led to various issues, resulting in closure or dismantling of many Small hydropower plants. To maximize the positive impact of Small hydropowers, green transformation and Small hydropower plant upgrades are urgently required. Hence, Small hydropower refurbishment activities are performed to enhance overall benefits. Therefore, this study integrated grounded theory, a qualitative research method, with a comprehensive decision-making trial and evaluation laboratory-fuzzy analytic hierarchy process evaluation model. This formed a new framework to analyse refurbishment activities and was applied in Tangban and Maoyandong plants. Small hydropower refurbishment activity benefits were categorized as internal (direct economic and indirect production benefits) and external (social and ecological benefits), with interconnections and trade-offs. The most critical factors influencing benefits were internal factors, whereas social benefits had a greater influence on external factors. The refurbishment activities at Tangban and Maoyandong were rated high and moderate, respectively, owing to differences in corporate nature, location, and primary business focus. This study not only provides a theoretical model for China's Small hydropower to achieve the United Nations Sustainable Development Goals under the premise of sustainable operations, but also offers a new global framework for evaluation and decision-making in Small hydropower plants. [Display omitted] • Small Hydropower Refurbishment Activities tackle the challenges of small hydropower in China, enhancing its sustainability. • A new comprehensive framework for Small Hydropower Refurbishment Activities has been proposed, combining qualitative analysis to identify benefits with quantitative methods to identify key factors and assess overall benefits. • This new benefit framework can provide decision-making support for the development of small hydropower projects tailored to local conditions. • The sustainability of Small Hydropower Refurbishment Activities require the role of the market, as well as the support of government policies. [ABSTRACT FROM AUTHOR]

Current trends in the global energy market focus on gradually increasing the share of renewable energy sources in the overall energy mix. In recent years, there has been growing interest within the scientific community in assessing the suitability of cities for implementing solar energy solutions. This work discusses various research directions on the solar potential of urban areas, with a particular focus on the role of Geographic Information System (GIS) tools in support of spatial analyses. The main aim of the study was to update the current state of the research based on the analysis of previous works. An attempt was made to assess the role of GIS in research on the solar potential of cities in the context of the overall investigation process. A total of 201 case studies published between 1999 and 2024 (year to date) were analysed, among which articles from 2019–24 were examined in detail. The analysis revealed a wide variation in the approaches regarding the spatial scale of studies and the sources of key data, such as shading and solar radiation. It was shown that one of the key challenges in current analyses is the lack of universality of the methodologies used, leading to divergent, and sometimes challenging to compare final results. In the research aspect, a global urban solar potential was estimated for cities with more than 1 million inhabitants, which amounted to 33.7 PW h annually. [Display omitted] • The state of research on the solar potential, with a focus on articles from 2019 to 24. • The historical context of the research is outlined. • Approaches to the analysis of radiation, shading, and the spatial scale used were addressed. • An analysis of the global potential for cities >1 mln inhabit. Estimated at 0.39 TW. [ABSTRACT FROM AUTHOR]