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Energy transition requires a high penetration of reliable and flexible renewable energy. To do so, low-cost, efficient, high capacity and environmentally friendly storage technologies to manage the mismatch between energy production and demand are required. Carnot Batteries are considered as promising energy storage solutions tackling these requirements and storing electrical energy as thermal energy and releasing it whenever necessary while operating on reversible thermodynamic cycles. In Carnot Batteries, power is managed through rotating machines, such as compressors and turbines, and energy is stored as heat in thermal energy storages. In recent years, thermal cycles exploiting Carbon Dioxide (CO 2) as operating fluid, in sub-critical, trans -critical and supercritical conditions, are gaining major interest, thanks to their versatility and high performance, especially for large scale applications. This paper provides an in-depth review on the state of the art of global R&D activities on the use of carbon dioxide for large scale Carnot Battery application, while providing preliminary market and technology maturity breakdown. Different studies on CO 2 -Carnot Batteries at industrial and academic levels are discussed in detail while highlighting the novelty and improvement methods. Detailed information on battery parameters of charging, discharging and storage have been listed and critically analysed, finally concluding with SWOT (Strength, Weakness, Opportunity, Threats) and TRL (Technology Readiness Level) analyses for future developments. [Display omitted] • Academic and industrial outlook on CO2-Carnot batteries. • Important design parameters of charging, storage and discharging are tabulated for each study • · Critical analysis of the design parameters and performance • Roadmap for future developments on CO2-Carnot batteries [ABSTRACT FROM AUTHOR]

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

Research on power system resilience has increased due to frequent natural hazards. Many reviews have been performed on power system resilience, focusing on specific topics such as the application of energy storage systems and microgrids for resilience enhancement. To comprehensively analyze the work carried out on power system resilience, this paper presents a methodology to perform quantitative analyses that combines bibliometric and correlation analyses. For this reason, 851 research publications from popular databases, namely Scopus and Web of Science, spanning from 2001 to 2022, were obtained for analysis. In the quantitative analysis, bibliometric measures are evaluated and analyzed to identify the most productive elements (e.g., countries, papers, journals, and institutions), keyword co-occurrences, and track the thematic evolution of authors' keywords. Additionally, hazard metrics such as risk against natural hazards and word count of natural hazards are proposed to reflect the event-specific risk level of a country and its progress in event-specific resilience research. These metrics are later utilized to perform correlation analyses along with bibliometric measures. This correlation aims to identify lesser-explored natural hazards and countries with the potential for event-specific resilience studies. Overall, this study offers insights into power system resilience trends and emerging areas. It emphasizes less-attended, highly exposed natural hazards, helping prioritize research for future resilient models to address their unique challenges. • Bibliometric and Correlation Analyses were performed using 851 resources. • Identify top countries, institutions, journals, and cited papers. • Perform keyword co-occurrence, its evolution, and visualize trends using diagrams. • Correlation analysis between resilience publications and risk of natural hazards. [ABSTRACT FROM AUTHOR]

From the perspective of the system, cascade phase change energy storage (CPCES) technology provides a promising solution. Numerous studies have thoroughly investigated the critical parameters of the energy storage process in the CPCES system, but there is still a lack of relevant discussion on the current status and bottlenecks of this technology. Therefore, in this paper, 133 papers up to 2023 have been analyzed and visualized to indicate the tendency of CPCES technology. It has been revealed that the CPCES system can ensure the ratio of latent and sensible energy stored in each layer of phase change materials maintains about 2.5, which effectively improves the energy storage efficiency. Accordingly, this paper analyzes the energy, exergy, and entransy dissipation of the CPCES system to figure out the most capable method. The influence of various parameters on the performance of the CPCES system is thoroughly investigated, and a range of recommended values are provided for subsequent studies. Moreover, the economics of CPCES systems is analyzed concerning the characteristics of typical CPCES applications, and the applicability of the technology is revealed. Finally, the ongoing trials that CPCES technology will meet are identified, together with a discussion of trends and opportunities for how to address the challenges. This review provides valuable guidance for future research, development, and innovation of CPCES systems and is expected to attract more attention from researchers and scholars to the provision of advanced CPCES technology. • The systematic research and analysis of CPCES technology are elaborated. • Theoretical, simulation, and experimental studies of CPCES technology are summarized. • The pros and cons of the typical CHTES system are presented. • The influence of relevant parameters on CPCES configuration is depicted. • The existing challenges and future insights for CPCES technology are discussed. [ABSTRACT FROM AUTHOR]

Energy storage technology is recognized as an underpinning technology to have great potential in coping with a high proportion of renewable power integration and decarbonizing power system. However, the costs of energy storage facilities remain high-level and it makes energy storage a luxury in many application fields. To address this issue, a new type of energy storage business model named cloud energy storage was proposed, inspired by the sharing economy in recent years. This paper presents a review and outlook on cloud energy storage technology. The paper starts with the introduction of the basic concept, fundamental structure, and superiorities of cloud energy storage. Facing the energy storage utilization demands of the users on the source side, grid side, and demand side, the typical application scenarios of cloud energy storage are analyzed, and the corresponding state-of-art pilot trials are introduced. After that, the theoretical research framework of the cloud energy storage technology is presented, and the research status of cloud energy storage technology is surveyed. Finally, considering the combination of cloud energy storage and other advanced energy and information technology such as multi-energy coordination and blockchain, the evolution path and development prospects of cloud energy storage are discussed. • Basic attributes including concept, framework and superiorities, as well as corresponding pilot trials of cloud energy storage for different application scenarios are concluded. • The achievements, shortcomings and key research directions of the three most concerning areas of cloud energy storage technology are summarized. • The development prospects of cloud energy storage technology considering the combination with multi-energy technology, virtual energy storage and distributed information technologies are analyzed. [ABSTRACT FROM AUTHOR]

Over the past decade, energy storage in renewable energy-dominated systems has received increasing interest. Effective energy storage has the potential to enhance the global hosting capacity of renewable energy in power systems, accelerate the global energy transition, and reduce our reliance on fossil fuel-based generation. Pumped hydro storage (PHS) is the most common storage technology due to its high maturity, reliability, and effective contribution to the integration of renewables into power systems. Accordingly, it is essential to achieve the optimal operation of energy systems combined with PHS. Therefore, this paper comprehensively reviews recent efforts toward the optimal operation of PHS-based energy systems (PHS-BES), considering the diversified energy sources, configurations, grid connectivity, and research directions. The evaluation criteria for the optimal operation of these systems are mathematically addressed and discussed. Moreover, methods of solving the studied problem are categorized and several improvements are suggested. It is observed that more flexible energy policies are urgently needed to encourage new investments in PHS, and the existing environmental and social criteria require further research. Moreover, the hybridization of PHS with other storage devices should be further investigated, and the development of robust hybrid methods for solving the optimal operation of PHS-BES, especially for real-time applications, is highly promising. Based on an in-depth analysis, this paper provides a compendium of real-world research and industry-oriented challenges, and presents future research and industry trends for the optimal operation of PHS-BES. • The latest studies on the optimal operation of PHS-BES are reviewed. • PHS-BES are categorized based on the number and type of integrated energy sources. • The evaluation criteria and solving methods for the optimal operation of PHS-BES are discussed. • A compendium of real-world research and challenges is presented. • Future research on PHS-BES is concluded. [ABSTRACT FROM AUTHOR]

Ocean renewables (such as offshore wind and wave) are abundant and essential energy resources for supporting future emission-free targets. However, their energy intermittency and high cost have hindered commercialization and wide-scale implementations of these ocean energy technologies. This paper focuses on both issues and aims to increase the dispatchability of ocean energy farms by investigating the potential of a hybrid wind and wave energy platform with energy storage systems (ESS). This research introduces an innovative method to assess the necessary ESS capacity for offshore renewable energy farms, ensuring energy dispatchability to the local demand. In addition, the key criteria and the economic feasibility of deploying ESS in offshore energy farms are also discussed. A life-cycle cost model is presented that quantitatively compares different farm configurations, specifically a standalone offshore wind farm and a hybrid configuration incorporating both wind and wave generation systems. The results indicate that the combined wind and wave energy farm significantly reduces the ESS requirement and provides competitive lifecycle costs compared to the stand-alone wind energy farm, though the amount of these benefits vary on the local resource characteristics. The quantitative assessment presented in this study also provides realistic and practical justifications for combined energy farms that complement statistical conclusions derived from variability indexes in previous studies. [Display omitted] • The techno-economic benefits of combined wind–wave farms are quantified. • A novel method of sizing and evaluating ESS for offshore farms is proposed. • The combined energy farm reduces ESS requirement compared to wind-only farms. • The benefits of combined energy farms are sensitive to the resource characteristics. [ABSTRACT FROM AUTHOR]

Alongside the concern for environmental sustainability, the concept of Circular Economy, a term for an economic system designed to regenerate itself, has gained momentum. Circularity finds full expression in Local Energy Communities (LEC), a newly emerging setup wherein the local energy needs of a community are met independently, through the choice of shared solutions for energy production from renewable sources. Erstwhile the use of stationary energy storage systems for self-consumption optimization, load management, peak shaving, backup power and ancillary services, would foster the value of these Local Energy Communities. In this paper, we design a techno-economic analysis to assess the impact of the usage of Second-life Batteries for increasing the energy self-independence of those communities. A cost-minimization approach with technical and economic constraints is used for the analysis and is applied to a use case of Italy. This paper assesses the benefits that a Local Energy Community can entail while considering self-consumption maximization of PV generation, load shifting and grid balancing needs, while addressing the problem of high storage costs through the exploitation of second-life electric vehicles (EV) batteries, adding an extra layer for circularity. Scenarios related to maximizing the self-consumption of photovoltaic generation and demand side management are designed considering four different LEC technology configurations. The results confirm LEC viability, showing lower energy bills for each scenario and greater benefits coupling a solar generation system with a storage solution. • Development of a techno-economic tool for Local Energy Community. • A feasibility analysis of Second Life Batteries is performed for the energy community. • Increased economic and energy savings are observed with second life batteries. • Second life of batteries are economically feasible for the community at 150€/MWH. [ABSTRACT FROM AUTHOR]

Many studies have been conducted on the distribution network expansion planning (DNEP) problem in recent years. The primary goal of this issue is to satisfy electric load demand, taking into account economic and technical considerations. In the past, this planning was done in a centralized manner with all the information available. The restructuring of power networks and the emergence of renewable energy sources (RESs), energy storage systems (ESSs), and new market players with different interests have led to extensive changes in the DNEP issue. Subsequently, the solving methods of the DNEP problem will be important because many new goals, constraints, and other factors have caused the problem to become non-linear and non-convex. This paper prepares a comprehensive study on the DNEP problem from different aspects such as objective functions and constraints, design variables, planning horizon and phases, planning and system types, uncertainty, distributed generations (DGs) and storage units, planning level, solving methods, load models, and environmental issues. Finally, future research trends such as handling the conflicts, solving approaches, and other points facing the DNEP problem are suggested. • A comprehensive survey of studies that address the distribution network planning. • Proposing posterior approaches for the solving the DNEP problem. • Proposing bi-level model to consider medium and low voltage networks, simultaneously. • Providing suggestions for further research works. • A discussion about future work/research/challenge trends for the DNEP models. [ABSTRACT FROM AUTHOR]

Renewables around the globe, provide fuel diversification, energy security and produce little or no emissions during the electricity generation. The unavailability of rotating masses prohibits on-grid renewable energy generation systems from providing inertia during a frequency disruption. This would be extremely unsettling and impactful when the proportion of energy in the grid due to renewables is high. India currently, has a 28.04% share of on-grid renewable energy. The grid infrastructure systems of India would face severe challenges when the share of on-grid renewables leaps past 50% in the future. Thus, this paper primarily addresses the repercussions of increasing share of on-grid renewables in terms of inertia and frequency response in India. The energy scenario of 2040 in India under 80% proliferation of on-grid renewables has been well reviewed in this paper. The novelty of this paper is the narrative literature review of the Indian Electricity Grid Code (IEGC) on frequency response which is unique and exclusive to this manuscript. It demonstrates the current strategies prevalent in the grid system of India towards frequency response and inertia support. This paper also explains the diverse control strategies and energy storage technologies required for adoption with the on-grid renewables in India for frequency response. The other novelty in this paper is the insight about the inertia lost due to an on-grid 100-kW p solar photovoltaic system to explain the readers about the impact when the integration is hundreds to thousands of kilowatts. • Share of renewables in the Indian grid network is 28.04% (113.226 GW) as of 2022. • India aspires to achieve 54% share of on-grid renewables by 2030 and 80% by 2040. • Indian Electricity Grid Code indicates need for expansion in active power reserves. • India requires diverse control strategies and energy storages for inertia support. • On-grid 100-kW p solar photovoltaic system loses inertia of 100-kW for 4.44 s. [ABSTRACT FROM AUTHOR]

Seasonal thermal energy storage can provide flexibility to smart energy systems and are characterised by low cost per unit energy capacity and varying applicability to different geographical and geological locations. This paper identifies applications and reviews modelling approaches for seasonal thermal energy storage technologies in the context of their integration in smart energy systems. An example district-scale smart energy system is outlined to analyse three potential smart applications for seasonal thermal energy storage: (i) utilisation of multiple renewable energy sources, (ii) integrating waste heat and cool, and (iii) electrical network balancing. The rest of the paper focuses on modelling methods for borehole thermal energy storage and aquifer thermal energy storage in energy system analysis. Energy system tools for planning and detailed design stages are reviewed. Gaps are identified for planning tools in control strategies and open code. TRNSYS is found to be the dominant detailed design tool used to model large-scale borehole thermal energy storage. Co-simulation methods involving detailed physics and power system tools are also reviewed, including studies using co-simulation of a detailed physics tool to represent borehole or aquifer thermal energy storage alongside an energy system tool. A gap exists in co-simulation of borehole or aquifer thermal energy storage models with energy system tools capable of simulating both electricity and heat. In conclusion, seasonal thermal energy storage can provide flexibility through different smart applications at different scales, and modelling approaches using co-simulation methods offer a promising avenue for capturing potential benefits of these smart applications. • Three smart applications of seasonal thermal energy storage are explored. • Integrating multiple energy sources, waste heat, and electricity network balancing. • Modelling STES using planning and detailed energy system tools is reviewed. • TRNSYS dominates studies in the detailed energy system modelling tools category. • Co-simulation methods can capture potential benefits of smart applications. [ABSTRACT FROM AUTHOR]

The intermittency nature of renewables adds several uncertainties to energy systems and consequently causes supply and demand mismatch. Therefore, incorporating the energy storage system (ESS) into the energy systems could be a great strategy to manage these issues and provide the energy systems with technical, economic, and environmental benefits. Among all energy storage systems, the compressed air energy storage (CAES) as mechanical energy storage has shown its unique eligibility in terms of clean storage medium, scalability, high lifetime, long discharge time, low self-discharge, high durability, and relatively low capital cost per unit of stored energy. In contrast, low roundtrip efficiency (RTE), low depth of discharge, and high response time are considered its main drawbacks. This paper presents a comprehensive review of technological developments in CAES systems, including its design criteria and emerging application potentials. Furthermore, a detailed review of the most recent research progress on CAES technology and its challenges is presented from the point of view of the different integration potential of CAES, optimal designing, and scheduling with the role of CAES towards micro-grid, distribution energy network, and energy market environment. Finally, the limitations and future perspectives of CAES are described and summarized. This paper presents a comprehensive reference for integrating and planning different types of CAES in energy systems for various applications. • A review of the CAES practical applications and characteristics is carried out. • A comprehensive classification and comparison of various CAES are given. • The concept of CAES integration with energy conversion systems is introduced. • Different approaches for sizing the CAES components are presented. • CAES's optimal scheduling is discussed from the energy market, distribution network, and microgrid perspective. [ABSTRACT FROM AUTHOR]

The paper presents an enhanced scheme to control the dynamic response that can be delivered by distributed generation (DG) and renewable energy resource (RER) to be more reliable and stable than other electric systems. Robust Adaptive Emulated- Controller (RAEC) has been included to control and tune the adoption of controller parameters across a broad range of operating conditions. Some existing challenges related to high loading profiles that will be handled by new performance features. The objective of paper is to propose robust adaptive emulated-controller that is incorporated with high-speed fluctuations and dynamic energy systems. That can achieve an integrated system to reflect the enhanced structure and operation of electric systems, in addition to, Enhanced Mud Layers (EML) optimization will be applied to control and optimize the performance parameters. • A novel robust system is proposed to enhance the sustainable energy and renewables operation and dynamic performances. • The proposed technique supports the implications of energy resources for the sustainable communities and networks. • There are scenarios to consider the changes in the loading profiles, beside to the uncertain conditions. • The obtained results by the proposed technique have been appraised and examined. [ABSTRACT FROM AUTHOR]

In this review paper, the state-of-the-art vehicle-to-everything (V2X) mode operation of electric vehicles (EVs) is discussed. All the other modes of operation which are enabled by the V2X functionality of the system like Vehicle-to-Grid (V2G), Vehicle-for-Grid (V4G), Vehicle-to-Vehicle (V2V), Vehicle-to-Home (V2H), and Vehicle-to-Load (V2L) are discussed in detail. The V2X functionality is used to provide various services to the system like regulation of active power demand, reactive power compensation, shaving peaks and filling valleys in load demand, frequency and voltage regulation, compensation of harmonics in grid current. The techniques which are used to control the EV in V2X mode to impart the above-mentioned services are included. The advantages and limitations of these techniques are also discussed in this paper. The interaction among different modes of operation of EVs like V2G, V4G, V2V, V2H, and V2L is studied. Battery degradation, cyber-attacks, time-delays encountered in communication channels, and stability issues are the major challenges that may pose the threat to the resiliency of the V2X system. These dominant challenges are included in this paper. The methods which are used to enhance the resiliency of the V2X system against these issues are discussed as the scope of future work. • The paper provides a comprehensive review on vehicle to grid operation of electric vehicles. • The paper provides a comprehensive review on vehicle to everything operation of electric vehicles. • The services providing by utilizing the energy storage in electric vehicle to the system is discussed. • The associated with vehicle to every mode of operation of electric vehicles and its future perspectives are discussed. [ABSTRACT FROM AUTHOR]

This paper introduces the recent developments in Renewable Energy Systems for building heating, cooling and electricity production with thermal energy storage. Due to the needed Clean Energy Transition in the many countries and regions and the goal of closing Net Zero Energy Buildings, it is crucial to provide efficient Renewable Energy Based heating/cooling systems for buildings. The buildings contribute about 40% of total energy consumption, with significant potential for primary energy savings. The application of various Renewable Energy based systems is discussed including: the presentation of Hybrid Renewable Energy bases systems, methodology for their design and methods for the optimisation of Buildings RES. At present, mostly the systems based on heat pumps and photovoltaics are applied in buildings. However, the sources of those energy systems are unstable, and they are influenced by the climate environment. It makes it necessary to combine thermal and electrical energy storage, to achieve high efficiency. The recently developing electrical energy and chemical storage are Battery Energy Storage Systems and Hydrogen Energy Systems, through it is urgently necessary to overcome the difficulties of high cost, relatively low efficiency and demanding storage environment and so on. For the thermal energy storage, Phase Change Materials (PCMs) show great potential for application – with their use the thermal energy can be accumulated at the time of low energy demand or availability and recovered during a high consumption period. This review also presents the recent developments in PCMs for their application in buildings, both for heating and cooling. Finally, it sorts out some challenging issues of the RES today and guides future development. • The recent developments in Renewable Energy Systems for buildings accessed. • Reviewed papers relevant to the Integration of Renewable Energy Systems in buildings. • The recent developments in PCM thermal energy storage in buildings are evaluated. [ABSTRACT FROM AUTHOR]

The inherently advantageous geographical location of East and Southeast Asia provides a great potential for the development of diverse ocean energy technologies along its densely populated coastlines. This review paper focuses on the flexibility and feasibility of emerging ocean energy technologies in this region, including wave, tidal and ocean-current energy converters, floating photovoltaics, and offshore wind-turbines. Recent research on wave energy in the region has achieved advancements such as modifying oscillating water columns to exchange higher pneumatic energy, reshaping oscillating devices to capture more kinetic energy, and improving overtopping converters to absorb more incident waves. Regarding tidal energy, the paper reviews barrage-based and stream-based turbines and investigates the efficiency improvement, flexibility enhancement and adaptation to the unique regional features. Regarding ocean current energy, research on low-velocity turbines and optimized energy storage systems has made their application in the region more competitive. In addition, offshore deployments of floating photovoltaics have recently drawn the sector's attention and are beginning to emerge in the region, although their robustness against extreme weather and wave conditions should be addressed. Furthermore, compared to other ocean technologies, offshore wind technologies have attracted the most investment in the region. Due to the fluctuation of wind-energy generation, enhancing the energy flexibility to increase its grid penetration has become a recent focus in both the academic and industrial communities. However, despite the good research and demonstrations, most of the abovementioned ocean technologies still encounter considerable techno-economic and techno-environmental challenges that limit their competitiveness in the East and Southeast Asian markets. • State-of-the-art review of advanced ocean energy technologies for Asian Regions. •Regional ocean energy review regarding energy flexibility potential and challenge. •Recent progresses and ocean energy potentials in East and Southeast Asia. •Future development and challenges of ocean energy in East and Southeast Asia. •Ocean energy applications in the densely-populated coastal regions and challenges. [ABSTRACT FROM AUTHOR]

Electricity Market is structured to fund reliable electricity supply, meet the need of consumers, ensure the affordability of end-users, and support national economic development. In recent years, to meet challenging emission target set by Government, power system in the UK has a rapid increase of integration with various-scale Renewable Energy Sources (RESs) and Energy Storage Systems (ESSs), which pushes the electricity market reform to accommodate the changes, encourage renewable energy integration, adopt new technologies, stimulate consumers participation, and ensure the power system resilience. The paper reviews the history of UK electricity market evolution, driving factors of reform, and the trend of current electricity market reform. In history, the UK electricity wholesale market has experienced three significant reform stages, which are introducing the Electricity Pool of England & Wales (the Pool) in the 1980s, implementing the New Electricity Trading Arrangements (NETA) in the 2000s, and performing the Electricity Market Reform (EMR) in 2013. To address the new emerging challenges in decarbonising power generation, the paper explains and analyses on-going electricity market changes and the trend for future electricity market reform. • Comprehensive review of UK electricity market mechanism and its history of evolution. • Explanation of the major UK electricity market reforms and the rational for all the reforms. • Clarification of the importance of electricity market in encouraging increases of renewable energy integration. • Analysis the trend for the future electricity market evolution. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) are widely used as a critical energy storage system for internet of things (IoT), electric vehicles (EV) and various renewable energy sources. However, the widespread use of LIBs has resulted in the significant accumulation of batteries with different chemistries in landfills. Existing methods for LIB recycling are unsustainable, non-environmentally friendly and ineffective at recycling spent LIBs with mixed chemistry. These methods are inadequate to achieve recovery and repurposing of the valuable and sometimes toxic components. This mandates an inherent need to improve the existing processes or develop a novel, sustainable, environmentally friendly and effective alternative process. In this paper, we present a comprehensive review of the current recovery technologies; demonstrating the gaps in understanding, the challenges and opportunities available in the recycling processes. This review will also examine and discuss different fundamental scientific principles and methods that can be employed to develop sustainable and effective recycling processes with an aim to facilitate the LIB recycling industry to shift towards a circular economy. • Challenges of repurposing mixed chemistries spent LIBs. • Comprehensive mechanistic insight into different recycling methods. • Advantages, disadvantages and proposed modifications of current recycling methods. • Thorough discussion on novel solvometallurgy based recycling methods. • Conversion of spent LIBs into value added products through combinatorial approaches. [ABSTRACT FROM AUTHOR]

Curtailment of distributed photovoltaic (PV) and battery energy storage systems will have significant implications for power system transition around the world. Australia offers a unique case study as it has highest installation rate of distributed-PV and growing fleet of battery energy storage systems. Distributed-PV and battery inverters in Australia are required to exhibit voltage-responsive power-quality response modes to prevent excessive voltage rise caused by increasing day-time energy exports, but these modes can curtail power output and limit the value that can be gained from the renewable energy assets. For the first time in Australia, this paper studies all three inverter power-quality response modes and develops novel algorithms to assess curtailment. The algorithms are applied to a real-world dataset of 1-sec distributed-PV and battery power measurements from 1300 residential households; therefore, data resolution is higher and sample size is larger than previous related studies. Using these datasets, the study compares the experienced curtailment between distributed-PV only sites and distributed-PV coupled with battery sites for the first time. The study investigates and quantifies the energy loss due to curtailment within the South Australia region with over 40% distributed-PV penetration which has the highest uptake in the world. The results show that average curtailment loss was 1.5% for distributed-PV only sites and 0.2% for distributed-PV coupled with battery sites, however, some sites were heavily impacted losing up to 25% of generation. The reasons for the larger curtailment loss were identified as wiring and network connection faults and high voltage set-points at households' respective local substations. Other potential reason for the heavily impacted sites is being located towards the end of the low voltage feeder, however this couldn't be verified due to lack of spatial data. The large variation in curtailed generation across sites raises concerns for system owners and suggests further inquiry into the power-quality response mode design and regulations. The study also examines inverter conformance using real-world operational data for all three power quality response modes for the first time, and the results showed a low rate of conformance according to the Australian Standards and there were various discrepancies in the execution of these modes which raises concerns considering the increasing importance of distributed-PV and battery inverter fleet in supporting network operations and security. The results therefore warrant further investigation into the reasons behind these discrepancies and devising appropriate mechanisms to tighten inverter conformance checks. • Energy curtailment is calculated for D-PV only and D-PV coupled with BESS sites • Average loss due to curtailment is less than 2% of total D-PV generation • Curtailment is greater for D-PV only sites than D-PV coupled with BESS sites • Some sites lose up to 25% of generation due to curtailment • The large variation of curtailment losses across sites raises concerns • Inverters showed low conformance in power quality response mode standards [ABSTRACT FROM AUTHOR]

This paper provides a review of negative carbon capture technologies. Based on these technologies, here it is proposed an innovative negative emissions power plant combining the generation and storage of energy from biomass, photovoltaic, and concentrated solar power, capturing and recovering CO 2 by producing H 2 or CH 4 as green energy carriers. The main features of the system are i) large-scale energy production system with negative CO 2 emissions; ii) 100% renewable system based on biomass and solar energy with the possibility of integrating other renewables; iii) synergistic integration of processes and systems; iv) recovery of O 2 generated by photovoltaic-driven electrolysis within the process of partial biomass oxycombustion and v) solar-driven limestone calcination. A detailed model of the entire plant is developed to evaluate the integration of the process. The model performance is assessed on an hourly basis throughout the whole year. The base case results show an energy consumption from 1 to 2.1 MJ/kg CO 2 to capture 60–77% of CO 2 emitted from the biomass plant and green methane production of more than 7500 tons/year. The negative emissions associated with the process are -612 kg CO 2 /MWh. It justifies the interest in the proposed negative emissions power plant. [Display omitted] • A synergetic integration of CO2 capture, energy storage and methane production is proposed. • A biomass power plant is considered, resulting in -612 kg CO2/MWh negative emissions. • Solar PV and CSP are integrated into the process to reduce the SPECCA to 1–2.1 kg CO2/MWh. • A large amount of solids storage is required to achieve 70–90% CO2 capture capacity. [ABSTRACT FROM AUTHOR]

The development of off-grid hybrid renewable energy systems (HRESs) is essential to rural electrification and global decarbonization. Based on 299 journal papers in the recent five years, this work conducts a state-of-the-art qualitative review and quantitative bibliometric analysis on the sizing optimization of off-grid HRESs. An overview of system configurations, energy management strategies, performance evaluation indicators, and sizing methodologies are presented, and bibliometric analysis is conducted to reveal the overall scope and mainstream of this research field. Finally, promising future works are summarized on the basis of current research gaps. The results of bibliometric analysis indicate that: (1) solar photovoltaic and batteries are the most common energy source and energy storage respectively, and wind-photovoltaic-battery-diesel is the most popular system configuration; (2) most researchers apply rule-based energy management strategies rather than optimized strategies, owing to their advantages of simple implementation and fast computation; (3) 97.99% of articles considers economic indicators in the sizing optimization model, and techno-economic feasibility is the essential research foundation at the planning stage; (4) meta-heuristic algorithms and the HOMER software tool are the two most popular sizing methodologies for off-grid HRESs. In future works, hybrid energy storage systems, deep reinforcement learning-based energy management strategy, sustainability and resilience indicators, as well as distributionally robust optimization-based sizing methodologies are promising research directions. Overall, the presented overviews and outlooks can provide holistic theoretical knowledge about sizing optimization research for practitioners, thus promoting the academic progress and practical implementation of off-grid HRESs. • Qualitative review and quantitative bibliometric analysis on energy system planning. • Overview of conventional and emerging renewable energy and storage technologies. • Classification of energy management strategies integrated with sizing optimization. • Multi-perspective projection of future works based on current knowledge gaps. [ABSTRACT FROM AUTHOR]

The growing need to alleviate the environmental impact of fossil fuels demands further technical growth in fuel cell hybrid electric vehicles (FCHEVs). Due to the dynamic nature of electrochemical power resources such as fuel cells (FCs) with auxiliary energy storage systems (ESSs), a variety of power management strategies (PMSs) have been widely developed and analysed for optimal power allocation. In this paper, a comprehensive review of various PMSs is systematically investigated for data acquisition and management regarding the search strategy. Within the data collected, the classification and the performance of PMSs are analysed to determine their characteristics and objectives for optimisation process. Additionally, a thorough examination of various PMSs employed in marine industry provides insights into the research trends and challenges associated with FC and battery hybrid systems and particularly ship propulsion systems. Furthermore, a system-level approach to PMS is explored, highlighting the importance of considering the correlation between component sizing and control as well as a health-conscious management that can enhance cost-effectiveness and life cycle of a FC and battery electric ferry applications. • A comprehensive review of power management system (PMS) in fuel cell electric vehicles. • Detailed analysis of PMS classifications and features. • A review and analysis of PMS in fuel cell ferry. • Discussion of current issues and potential research of PMS in ship propulsion system. [ABSTRACT FROM AUTHOR]

Buildings account for about 39% of the total energy consumption in the United States. Developing highly energy-efficient and environmentally friendly systems that are either actively or passively integrated into buildings plays a crucial role in decarbonizing the building sector. Among various technologies, desiccant-based energy systems have received particular attention in recent years due to their unique advantages, such as being thermally driven using low-grade waste or solar energies and being reliable over a wide range of operating ranges. Extensive research efforts have been exerted on desiccant-enabled technologies at both material and system levels aiming to increase their performance and achieve high technological readiness levels. The present review paper comprehensively discusses research works made at the system level. It overviews desiccant-based air conditioning systems, desiccant-based humidity pumps, desiccant-based thermal energy storage systems, and desiccant-based appliances. The study identifies challenges and opportunities to accelerate the commercialization of desiccant-enabled technologies. It is found that desiccant materials offer great promise to improve energy efficiency and functionality of future buildings through decoupling the latent and sensible cooling loads in air conditioning systems, humidity pumps integrated into building facades, and next-generation appliances. However, commercial viability and widespread acceptance of desiccant-based systems have been hampered by several major obstacles, including liquid and air flow mal-distribution and inferior thermo-physical properties of desiccant materials resulting in low ab/adsorption and regeneration rates and bulky/costly systems. • Review the desiccant-enabled technologies at the system level. • Traditional desiccants suffer from limited performance in low-humid climates. • Humidity pumps integrate desiccants into the building facade. • Desiccant materials are promising for clothes dryers and dishwashers. • Identify challenges facing the commercialization of desiccant-enabled technologies. [ABSTRACT FROM AUTHOR]

Supercooling is a natural phenomenon that keeps a phase change material (PCM) in its liquid state at a temperature lower than its solidification temperature. In the field of thermal energy storage systems, entering in supercooled state is generally considered as a drawback, since it prevents the release of the latent heat. Conversely, when dealing with plants, animals or preservation processes, supercooling protects organs, tissues or blood from solidification that leads to damage or to death. This paper first reviews the most important applications and cases in which supercooling can take place and dramatically change the performance. Second, the paper discusses the factors affecting the occurrence and the degree of supercooling, such as cooling rate, PCM container characteristics, PCM thermal history, use of additives, etc. The paper includes a supercooling modeling section, which presents the main mathematical and numerical methods used to solve the challenges encountered by researchers. This review shows that to experimentally foster or reduce supercooling, most researchers tend to use similar methods such as controlling the cooling rate, changing container's characteristics or adding additives. The main challenge in supercooling modeling being its unstable and probabilistic nature, most authors tend to perform experimental measurements to obtain some key parameters, notably the supercooling degree, prior to the modeling. This strategy restricts the validity of the models to applications having the same conditions as the experiments. Nevertheless, this review offers the guidelines to select the appropriate experimental parameters and modeling strategies, depending on the specific and practical objectives of each application. • The advantages and disadvantages of supercooling in nature and different daily applications are reviewed. • The latest experimental studies are presented and factors affecting supercooling are discussed. • The challenges in modeling supercooling of PCM are presented. • The most used techniques to model supercooling are discussed. [ABSTRACT FROM AUTHOR]

Supercooling is a natural phenomenon that keeps a phase change material (PCM) in its liquid state at a temperature lower than its solidification temperature. In the field of thermal energy storage systems, entering in supercooled state is generally considered as a drawback, since it prevents the release of the latent heat. Conversely, when dealing with plants, animals or preservation processes, supercooling protects organs, tissues or blood from solidification that leads to damage or to death. This paper first reviews the most important applications and cases in which supercooling can take place and dramatically change the performance. Second, the paper discusses the factors affecting the occurrence and the degree of supercooling, such as cooling rate, PCM container characteristics, PCM thermal history, use of additives, etc. The paper includes a supercooling modeling section, which presents the main mathematical and numerical methods used to solve the challenges encountered by researchers. This review shows that to experimentally foster or reduce supercooling, most researchers tend to use similar methods such as controlling the cooling rate, changing container's characteristics or adding additives. The main challenge in supercooling modeling being its unstable and probabilistic nature, most authors tend to perform experimental measurements to obtain some key parameters, notably the supercooling degree, prior to the modeling. This strategy restricts the validity of the models to applications having the same conditions as the experiments. Nevertheless, this review offers the guidelines to select the appropriate experimental parameters and modeling strategies, depending on the specific and practical objectives of each application. • The advantages and disadvantages of supercooling in nature and different daily applications are reviewed. • The latest experimental studies are presented and factors affecting supercooling are discussed. • The challenges in modeling supercooling of PCM are presented. • The most used techniques to model supercooling are discussed. [ABSTRACT FROM AUTHOR]

This paper is the editorial for the virtual special issue (VSI) of Renewable and Sustainable Energy Reviews (RSER) dedicated to 4 SDEWES Conferences held in 2020, namely: (i) the 2nd Latin American Conference on Sustainable Development of Energy, Water and Environment Systems (LASDEWES 2020) held from February 9 to 12, 2020 in Buenos Aires, Argentina; (ii) the 1st Asia Pacific Conference on Sustainable Development of Energy, Water and Environment Systems (APSDEWES 2020) held from April 6 to 9, 2020 in Gold Coast, Australia; (iii) the 4th South East European Conference on Sustainable Development of Energy, Water and Environment Systems (SEESDEWES 2020) held from June 28, 2020 to July 2, 2020 in Sarajevo, Bosnia Herzegovina, and (iv) 15th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES 2020) held from September 1 to 5, 2020 in Cologne, Germany. The VSI collected both high quality review papers and original research articles presented at the 4 SDEWES conferences in 2020 belonging to the aims and scope of RSER. After a scrutinizing peer review process, 20 articles were accepted and published. These articles fall into four main areas: renewable energy cutting edge technologies, energy storage, energy modelling techniques and, climate and energy policy and impacts. Cross-areas articles belong to this Special Issue covering almost all the Sustainable Development Goals (SDGs). • The VSI SDEWES 2020 covers four main areas. • An overview of the renewable and sustainable energy challenges to be dealt. • Cross-areas studies help addressing SDGs. • The advances and the novel findings for the successful achievements of ambitious policy targets. [ABSTRACT FROM AUTHOR]

Recent advances in energy storage systems have speeded up the development of new technologies such as electric vehicles and renewable energy systems. In this respect, supercapacitors have gained interest due to their unique features such as high power density, long lifespan, and wide operating range. To achieve the high-voltage levels required for vehicular or utility applications, a supercapacitor pack should contain hundreds of high-capacity series-parallel cells. The internal states of these cells cannot be obtained by direct measurements and these states are usually affected by operating conditions such as temperature and noise. In addition, due to the uncertainty in the manufacturing processes, the characteristics between different batches or even the same batch of supercapacitor cells will be unavoidably different, which will impose significant challenges in terms of uniformity, functional safety, and durability of the system. Therefore, the supercapacitor pack will require a management system to effectively monitor, control, and protect the cells along all performance boundaries. Based on a comprehensive review of the latest articles and achievements in the field, as well as some useful previous experiences of the authors, this paper provides an overview of the key technologies, functionalities, and requirements for Supercapacitor Management Systems (SMSs). To the best of the author's knowledge, this is the first survey that provides an inclusive collection of key requirements for the SMS, including issues related to the modeling, estimation, control, and protection of the supercapacitors. The supercapacitor is a relatively new technology and no international standard about SMSs and their functional requirements are available up to date. The present survey will perfectly fill these gaps. In the survey, the key SMS requirements are broadly divided into the software and hardware functions, and several key issues including modeling and state estimation functions, control and balancing circuits, etc. Are covered. A comprehensive review of the supercapacitor/SMS vehicular applications is also provided in this paper. • Supercapacitors can be used as power buffers in e-mobility applications. • Supercapacitor packs face serious challenges regarding performance and functional safety. • SMS can monitor and control the supercapacitor pack along all performance boundaries. • An effective SMS improves the performance and lifetime of supercapacitor packs. • SMS functional requirements are comprehensively reviewed in this paper. [ABSTRACT FROM AUTHOR]

This paper presents a review of the application of model predictive control strategies to active thermal energy storage systems. To date, model predictive control has been used to manage such energy systems as heating, ventilation and air conditioning equipment or power generation plants. In all cases, the aim of the strategy has been to anticipate both production and consumption decisions to optimize the system performance, reducing the final energy cost. This ability of the strategy to forecast weather conditions and predict demand requirements in advance exceeds the performance of conventional control methods and made the strategy a very effective option to be coupled with active thermal energy storage systems. In this regard, this review paper presents the progress and results of the combination of these two technologies. The key contributions consist of a summary of the technical parameters employed, such as the prediction horizon length, the computational architecture approaches, the thermal energy storage material used and the influence of renewables in this kind of system. Additionally, the review summarises the latest enhancements to overcome computational issues and an analysis of the objective functions employed in each study, which were mainly focused to minimize the energy cost, the peak power and CO 2 emissions. A discussion about the strengths and weaknesses of this technology is provided, highlighting the difficulty of the strategy to operate with complicated physical models as the key limitation to overcome. Finally, some future guidelines to enhance the application of this strategy to control different sort of systems are detailed. • A review on MPC applied to heating, cooling, and power generation systems with TES. • MPC demonstrated to be a promising technology to minimize the operation cost. • Combining MPC and active TES increases the global system performance. • More research is needed on validating MPC strategies upon active TES systems. [ABSTRACT FROM AUTHOR]

To address the urgent environmental challenges of transportation related air pollution and energy shortage, hybrid electric vehicles (HEV) and battery electric vehicles (BEV) with potential for higher energy efficiency are gaining in popularity and gradually replacing those conventional vehicles. Extended range electric vehicle (EREV) is a subset of these new energy vehicles aiming to gain benefits of both HEVs and BEVs and provide a solution to reducing tailpipe emissions whilst providing satisfactory driving-range compared with tradition internal combustion engine (ICE) vehicle counterparts. This paper systematically introduces the current developments of EREV in terms of the powertrain structure, energy management and vehicle performance, while the two key focus areas of auxiliary power unit (APU) charging control and (hybrid) energy storage system ((H)ESS) power management. A case analysis on a typical EREV is presented to study the application potential. Comprehensive comparisons of popular APU control strategies and different energy storage dispositions are shared, several existing issues are also discussed in this paper. Furthermore, a general manufacturing cost analysis for different types of vehicles is presented, and the outlook of EREV for future research is presented. • A review and assessment of extended-range electric vehicle powertrain is done. • An evaluation of state-of-the-art energy management strategies is presented. • A case analysis on a typical EREV is conducted to study its thorough potential. • An investigation of general manufacturing cost for different hybrid vehicles is made. • Outlook and recommendations for extended-range electric vehicle is provided. [ABSTRACT FROM AUTHOR]

Liquid Air Energy Storage (LAES) systems are thermal energy storage systems which take electrical and thermal energy as inputs, create a thermal energy reservoir, and regenerate electrical and thermal energy output on demand. These systems have been suggested for use in grid scale energy storage, demand side management and for facilitating an increase in renewable power integration into the current power network. This paper presents a comprehensive review of LAES systems, ranging from the first known mention of LAES systems in literature to the most recent studies. This review covers liquefaction systems, power generation systems, integrated systems (combining LAES with other industrial processes) and physical LAES plant demonstrations. Although significant analysis of LAES systems has been done to date, there remains a gap between published LAES literature, and how LAES systems would operate optimally at large scale. To bridge this gap, future LAES research should involve multivariate analysis of LAES systems under dynamic, transient conditions, with the aim of identifying and potential design implications, and to further assess the operational and economic viability of LAES systems in use at large scale. This paper aims to achieve a holistic, critical review of all published work relating to LAES systems. • LAES systems have the potential to be a competitive local and grid scale energy storage technology. • LAES systems can facilitate the penetration of renewable energy technologies. • Further analysis of dynamic conditions should be done, with the aim of identifying any potential design implications. [ABSTRACT FROM AUTHOR]

Energy conversion is one of the keys to the world's future renewable and sustainable energy infrastructure systems. The use of multidimensional late transition metal complexes-based nanostructures to realise the self-powered or energy-autonomous systems have led to the creation of mechanistic-catalytic synergies of materials functions. The system requires enhance interface architectures to recover and revolutionise those valuable materials-based resources. Hence, the purpose of the present work is to highlight the importance and the current progress of these latest generations of late transition metal nanocomplexes as a material source in renewable energy structure development. This paper reviews the fundamental mechanism steps in catalytic reactions with the focus of attention limited to the characteristic features of these late transition metals. Further on this, the developments in the field of self-powered of the late transition metal nanocomplexes, mainly focusing on their electrocatalytic reactions for energy conversion technology, comprises ORR, OER, and HER is reviewed. This is followed by a discussion on the current demand for the past five years in high-capacity renewable energy storage applications. Through the discussions, the optimisation and evolutionary changes in terms of selection, stability and scalability of late transition metal nanocomplexes are the factors that make them as a leader to suit the current energy landscape and for the next 25 years for prosperous, sustainable and affordable global energy future. This review will complement other papers on the energy transformation processes and storage that involve modern micro and nanotechnology, thus further boosting the over-all specific properties of transition metal complexes -based nanostructures. • The current development of late transition metal nanocomplexes for renewable energy conversion and storage is discussed. • Fundamental types of catalytic reactions involve late transition metals are discussed. • The available renewable energy technologies are discussed. • Types of energy storage that employed late transition metals as the core elements are highlighted. [ABSTRACT FROM AUTHOR]

Latent thermal energy storage (LTES) heat exchangers can provide energy storage in a broad range of energy systems. Implementing LTES heat exchangers requires an assessment of their performance in a given system. The performance of a LTES heat exchanger is described by its performance indicators which are classified as technical, economical, and life-cycle indicators. The current paper focusses on the technical performance indicator and specifically on predictive methods which aid the assessment of the performance of a LTES heat exchanger in a system. To structure the analysis, a thermodynamic framework is provided which allows to clearly define LTES heat exchangers and classify the technical performance indicators. In a second step, the literature is reviewed for reported technical performance indicators with a specific focus on predictive methods for these indicators. The averaged effectiveness-number of transfer units (ε-NTU) and phase change time method are identified as important predictive models, analyzed, and compared based on their theoretical derivation. The relation between the averaged effectiveness and phase change time is investigated both theoretically and based on data available in literature which results in recommendations for standardizing the characterization of LTES heat exchangers. By standardizing characterization of LTES heat exchangers, researcher can assess their performance in different energy systems without additional experiments or CFD calculations. • A thermodynamic framework is developed. • Based on the framework, reported performance indicators are categorized. • Predictive models for phase change time and effectiveness are derived. [ABSTRACT FROM AUTHOR]

Over the last decade, the demand for data center and network services has increased dramatically. To meet this demand, global average rack power density has risen from 2.4 kW/rack in 2011 to 8.4 kW/rack in 2020 with the aid of technological advancements. About 36% of global data centers have racks above 30 kW/rack. Average Power Usage Effectiveness (PUE) dropped from 2.5 in 2007 to 1.65 in 2013, but has been almost flat since then, at 1.59 in 2020. The depletion of finite fossil fuel reservoirs, adverse impact of greenhouse gas emissions on global warming, recyclability of electronic waste, and the rising cost of energy are pushing the datacom industry toward more energy-efficient and sustainable technologies including renewable energy, highly efficient electronics cooling, waste heat recovery, passive cooling systems, and energy storage, which are broadly reviewed in this paper. Use of renewable energy resources through power purchase agreements rose by 346% from 2.4 GW in 2017 to 10.7 GW in 2020. Air-side economizers can reduce PUE by 30–50% and water-side economizers by 10–30%. The server/rack outlet is an ideal spot for waste heat recovery and can be coupled with a multi-stage heat pump to save significant energy if coupled to a district heating system. Active and passive deployment of thermal energy storage can save more than 20% of cooling energy and reduce temperature fluctuations by more than 60%. Edge computing, decentralization, and virtualization can lead to lower latency, higher scalability, and reliability during failure. [Display omitted] • Average data center rack power has risen from 2.4 kW/rack in 2011 to 8.4 in 2020. • Average data center PUE went from 2.5 in 2007 to 1.65 in 2013 - has been flat since. • Data center renewable use grew 346% from 2017 to 2020 to 10.7 GW. • Air-side economizers can reduce PUE by 30–50% and water-side economizers by 10–30%. • Thermal storage can reduce data center cooling 20% and temperature fluctuations 60%. [ABSTRACT FROM AUTHOR]

Foam structure is a three-dimensional (3D) porous skeleton, which has been widely studied in the field of electrochemical energy storage due to its excellent structural properties, such as high specific surface area, suitable pore size distribution, fast ion transport channels and good stability. The special structure of foam improves the synergy between electroactive and substrate materials: the large specific area provides more growth sites, increasing the loading of active material; the interconnected network framework greatly shortens the transport path of electrolyte ions; the 3D pore space relieves stress effect from volume expansion of active materials. Due to these advantages, the prepared energy storage device has high energy/power density and good cycle stability. In this review, we summarize the preparation methods and structural properties of the foam-based electrode materials, such as metal foam, carbon foam, polymer foam and so on. Subsequently, we briefly introduce the important applications of foam-based electrodes in the related energy devices and other fields, such as supercapacitors, rechargeable batteries. Finally, based on these practical applications, we analyze the future development of the foam-based electrode materials. Schematic diagram of the application and classification of foam-based structures in advanced electrodes. [Display omitted] • Applications of foam structure in advanced electrodes are reviewed. • Characteristics of foam structure formed by several materials are introduced. • Internal mechanisms of the foam structure improving the electrochemical performance of the electrode are analyzed. • The paper suggests further development directions of the foam-based electrodes. [ABSTRACT FROM AUTHOR]

Open-cell metal foam has a great potential for manufacturing compact heat exchangers in energy conservation systems due to the advantages of large specific surface area and high thermal conductivity. In this paper, the research progress on the flow and heat transfer characteristics of fluids in metal foams was reviewed, including the distribution characteristics in fuel cells, heat transfer of phase change materials, convection of dry air and wet air, pool boiling, flow boiling and condensation. The research results show that the metal foam can be applied to improve the performance of fuel cells and enhance the heat transfer of phase changer material in thermal energy storage systems; the metal foam provides better heat transfer performance than the traditional slit fins under dehumidifying conditions, and the surface modification on metal fibers enhances the boiling and condensation heat transfer characteristics. The correlations for predicting the heat transfer and flow characteristics of fluids in metal foams were summarized. Recommendations for further investigations on metal foams were proposed based on the surveyed literature. • Main application and heat transfer characteristics of metal foams were reviewed. • Convection in metal foam was discussed. • Boiling and condensation characteristics in metal foams were summarized. • Correlation for predicting flow and heat transfer characteristics in metal foams was summarized. [ABSTRACT FROM AUTHOR]

Variable renewable technologies are characterized by a large degree of intermittency due to their natural variability, creating a need for exploiting a range of sources. In this context, the use of energy storage systems is often proposed. There are different ways to store and use the overproduced electricity from these technologies. This paper aims to evaluate the global warming emissions savings obtained from storing the surplus electricity from the variable renewable technologies in the Spanish market and later using it in different end use applications, both for the present day and the 2030 time horizon. First, a review of the life cycle assessments of different energy storage technologies published in the scientific literature is performed. Then, selected values from this review, adapted to the emission intensity of variable renewable electricity stored in Spain, are used to compute GHG savings from storing and using this electricity for different end uses. Results show that the highest benefits in terms of GHG emissions avoidance would be obtained in transport applications and in the power sector. However, as the electricity mix becomes decarbonized, the use of batteries behind the meter would lead to no GHG emissions avoidance. Using electricity to produce heat leads to low GHG emission avoidance benefits that will reduce over time. Benefits will improve in time for the chemical sector, as there are few alternatives to decarbonize this sector. A specific storage strategy must be formulated for each particular case. • The largest benefits are obtained using the stored energy in transport applications. • Using the stored energy in the power sector is also an option with high benefits. • The use of batteries behind the meter would have low or no benefits in the future. • Using electricity to produce heat leads to low GHG emission avoidance benefits. • A specific storage strategy must be formulated for each particular case. [ABSTRACT FROM AUTHOR]

Meeting decarbonization goals requires taking significant action on electricity systems, which are a major source of CO 2 emissions. Decarbonizing island electricity systems raises additional challenges due to their heavy historical dependence on fossil fuels and strict power-reserve and reliability requirements. To address this challenge, this paper presents a comprehensive optimization model for long-term capacity planning of island electricity systems. Our model determines an optimal mix of generation and transmission capacity to satisfy energy demand at least cost while respecting the strict technical constraints that are inherent in island systems. In addition, our model considers the use of thermal and renewable generation, electric vehicles providing electricity-system services, batteries, pumped-hydroelectric storage, and ac and high-voltage dc transmission lines. We demonstrate our model with a case study of the Canary Islands archipelago. Our results show that combining the aforementioned technologies reduces generation costs by up to 25% and capacity requirements up to 50% (relative to a case without the technologies). In addition, without any mechanism to internalize the social cost of carbon, fossil-fueled thermal generation is the lowest-cost source of energy. Environmental considerations demonstrate the benefits of renewable generation and result in these carbon-free energy sources supplying about 40% of the energy mix. [Display omitted] • Carbon pricing can increase renewable-energy supply up to 40%. • Energy storage reduce costs up to 23% and favors more renewable-energy capacity. • Transmission interconnectors reduce costs but do not increase renewable-energy use. • Combining technologies reduces costs by 25% and capacity requirements by 50%. • Strict reserve requirements may keep renewable-energy shares below 3%. [ABSTRACT FROM AUTHOR]

Due to the uneven distribution of renewable resources and electricity load centers in China, renewable energy usually needs to be delivered a long distance from the generation base to the load center. However, wind power and photovoltaic (PV) have to be bundled with flexible resources, such as thermal generators, to compensate for the generation uncertainty and variability. Concentrating solar power (CSP) is a controllable generation technology, and it is receiving great attention in the northwest China to be constructed in the 100% renewable energy generation base. This paper proposes a generation portfolio optimization model of a 100% renewable energy base supported by CSP. Firstly, a flexible operation model of CSP based on the interval theory is proposed. Then, a coordinated operation strategy of a 100% renewable energy base organized by CSP, wind power, PV and also energy storage is formulated. On this basis, a generation portfolio optimization model is established with the target of minimizing an extended levelized cost of energy (LCOE) considering the transmission cost. A case study of 100% renewable energy base in Qinghai Province, China, is conducted to verify the effectiveness of the proposed model. It is depicted that CSP plays an important role in the cost-effective portfolio and can be a better alternative to the combination of PV and storage. For the 100% renewable energy base in Qinghai, the LCOE with an optimal CSP, PV, wind, and storage combination is 0.5785 CNY/kWh, which is 20.3% lower than the case without the installation of a CSP station. • Building a 100% renewable energy generation base with a CSP, PV, wind, and storage combination. • A planning model with the target of minimizing an extended LCOE considering transmission cost. • A coordinated operation strategy of a 100% renewable energy base considering CSP's flexibility. • The LCOE of a 100% renewable energy base can drop 20.3% when equipped with CSP in Qinghai. [ABSTRACT FROM AUTHOR]

High and continuously increasing photovoltaic (PV) penetration in distribution network introduces many potential power system problems. One of the most important, and often the first to arise, is overvoltage issue. Although many measures have been proposed and implemented to solve the problem, a standardised metric to assess their economic viability is lacking. This paper introduces a PV levelised cost of integration (LCI) metric, which consists of all the capital and operational expenditures incurred when implementing the measures divided by the PV energy generated throughout its lifetime. The measures analysed are active power curtailment (APC), reactive power control (RPC), active-reactive power control (ARPC), as well as various battery energy storage (BES) measures. These measures were simulated on 69-bus and 119-bus distribution networks with real weather and electricity price data. Among the pertinent results are: (1) ARPC is the most cost-effective voltage mitigation measure, followed closely by RPC and APC, (2) BES cost needs to decrease by more than 80% for BES to be economically viable for overvoltage mitigation, and (3) change in reactive power charge, line losses, and BES roundtrip efficiency losses are all important components of LCI and need to be considered in assessing PV integration measures. The results and the LCI framework presented in this study can be used by policy makers, regulators, and researchers to evaluate renewable energy integration policies, methods, and algorithms. • PV Levelised Cost of Integration is proposed to evaluate PV integration measures. • PV active–reactive power control has the lowest levelised cost of integration cost. • Battery cost needs to decrease ¿80% before it becomes economical for PV integration. • The most suitable measure depends on the network's characteristics and priorities. [ABSTRACT FROM AUTHOR]

Many nations have encouraged the need to fully exploit renewable energy resources and energy-efficient technologies to address the issue of high electricity demand and reduce greenhouse gas emissions. The development of energy pathways and sustainable energy policies of diverse countries for long-term planning has always been a challenging task. This paper investigates the impact of alternative electricity development pathways on system costs and greenhouse gas emissions in Kenya. The Low Emissions Analysis Platform (LEAP) with Next Energy Modeling system for Optimization (NEMO) is used to evaluate the optimized least-cost power system and energy storage. Three scenarios are analyzed: high penetration of renewable energy resources with an energy storage system, internalizing of environmental externalities, and energy productivity. Results from the study indicate that with Kenya's Least Cost Power Development Plan 2017–2037 as the reference, the overall cost savings are up to 26.1 billion US dollars which is equivalent to 55% while the carbon emission saved with high penetration of renewable energy with storage is up to 6.3 Mt. On the other hand, energy productivity shows a downward trend with the existing policies and exhibits an upward trend when two policy instruments are considered. Consequently, those alternative energy planning pathways have the potential to significantly reduce overall system costs and GHG emissions. • LEAP NEMO is used to determine the optimal energy mix. • Simulation of energy storage provides for up to 3% of energy demand. • 6.3 Mt of CO 2 emissions are avoided. • Internalizing environmental externalities increases the costs of LCPDP. • Sustainable policy instruments increase energy productivity. [ABSTRACT FROM AUTHOR]

With the rapid development of smart grids, a smart microgrid structure that includes multiple homes and plug-in electric vehicles interacting in a distributed and coordinated manner is very promising. In this paper, three novel contributions are added according to the relevant literatures. First, a distributed energy management framework composed of three homes with photovoltaic (PV) power generation, second-life battery energy storage systems (SLBESSs), and EVs, is implemented. Then, the component modeling and the corresponding convex formulations are carried out using convex optimization, where the cycling aging model and calendar aging model of EV batteries need to be converted. Finally, the consensus alternating direction method of multiplier (C-ADMM) is employed to manage these three homes in a distributed manner and reduce electricity bills for the microgrid. Simulation results demonstrate that this distributed management method can reduce the whole electricity bills by 40.8% compared with the traditional separate management method and increase the self-consumption rate of renewable energy to 100%. Furthermore, EVs are recommended to avoid discharging to the household appliances as much as possible to reduce the battery aging cost and prolong the service life when plugged-in. The charging process should preferably take place before leaving for work in the early morning. • Consensus ADMM is used to manage multiple homes in a distributed manner. • A comprehensive economic analysis is implemented for multiple smart homes. • Calendar aging and cycling aging of EV batteries are considered. • Second-life batteries are used to reduce energy storage costs. [ABSTRACT FROM AUTHOR]

This paper compares various flexibility options to support renewable energy integration across the energy transition using energy system modelling. We analyse new flexibility assets such as electricity storage, heat pumps, demand-side response with existing wet appliances, electric boilers for domestic hot water and distribution grid expansion, along with energy efficiency measures in electrical appliances and building retrofitting. We propose an open-source sector coupling model (GRIMSEL-FLEX) to minimise, from a social planner perspective, the total cost of the energy system for electricity and residential heating supply in Switzerland, including various types of consumers and urban settings. We find relevant feedback mechanisms among various flexibility options. Firstly, electric boilers have a larger flexibility potential than demand-side response with wet appliances since they reduce storage investments by more than 26% by 2050 (only 12% for demand-side response). Secondly, 34% more electricity storage is needed if heat pumps replace all fossil-based heating and 80% to replace all heating systems entirely. Thirdly, we find a shift in the operation of heat pumps, electric boilers and wet appliances from night to midday, resulting in larger photovoltaic deployment (22%–66% for the residential sector). Finally, electricity storage capacity induced by heat pump deployment is highly dependent on the retrofitting rate. With 1% per annum, 86% of storage investments can be avoided and it can be counterbalanced with a high retrofitting rate of 2% per annum. • Open-source sector coupling modelling framework with different flexibility assets. • Optimal DHW boilers operation and DSR can save up to 40% of storage investments. • 34%–80% more electricity storage is needed to support larger heat pump deployment. • Retrofitting buildings reduces storage needs by 86%. • Flexible heat pumps, DHW boilers and appliances increase PV deployment by 22%–66%. [ABSTRACT FROM AUTHOR]

The penetration of the lithium-ion battery energy storage system (LIBESS) into the power system environment occurs at a colossal rate worldwide. This is mainly because it is considered as one of the major tools to decarbonize, digitalize, and democratize the electricity grid. The economic viability and technical reliability of projects with batteries require appropriate assessment because of high capital expenditures, deterioration in charging/discharging performance and uncertainty with regulatory policies. Most of the power system economic studies employ a simple power-energy representation coupled with an empirical description of degradation to model the lithium-ion battery. This approach to modelling may result in violations of the safe operation and misleading estimates of the economic benefits. Recently, the number of publications on techno-economic analysis of LIBESS with more details on the lithium-ion battery performance has increased. The aim of this review paper is to explore these publications focused on the grid-connected LIBESS applications and to discuss the impacts of using more sophisticated modelling approaches. First, an overview of the three most popular battery models is given, followed by a review of the applications of such models. The possible directions of future research of employing detailed battery models in power systems' techno-economic studies are then explored. • Overview of lithium-ion battery models employed in techno-economic studies of power systems. • The impact of various battery models on the decision-making problems in power systems. • Justification for more advanced battery models in the optimization frameworks. [ABSTRACT FROM AUTHOR]

Achieving carbon-free electricity for all can be facilitated by setting up small to medium-scale off-grid renewable energy systems (RES); however, the variability of renewable energy sources challenges system reliability. In this paper, we optimize a range of RES configurations considering different combinations of solar, wind, battery and pumped hydro storage for a specific location under diverse flexibility scenarios: one of load shifting (flexibility of power demand by changing consumption patterns by 0–30%), one of small load loss/shedding (0–5%), and one of both. Next, we quantitatively assess the impact of the flexibility options, renewable source and energy storage type impact on the microgrids' optimal energy management, cost, curtailment, and reliability level. The results show that RES utilizes 40–45% of added flexibility during particular day hours. The period of these critical hours is significantly affected by the RES type: namely the morning hours for battery storage-based RES while the evening hours for pumped hydro storage-based RES. The load shifting decreases the RES cost by 4–9%, but it does not reduce the overall system curtailment due to the substantial decrease in the energy storage size compared to the RE generator size when the load deferment is allowed. However, load loss scenarios not only reduced the RES cost by 30–50% but they also lessened the system curtailment by 40–51%. The off-grid RES cost can be reduced up to 60–67% by increasing the system flexibility. Moreover, the type of RE input source substantially impacts the system' self-sufficiency, energy served to energy generated ratio, and capacity factor, whose values vary in ranging 0.42–0.72, 0.18–0.5, and 0.13–0.23, respectively. [Display omitted] • Flexibility is crucial to reliable and cost-effective off-grid renewables. • Microgrid models are techno-economically assessed for allowed flexibilities. • Load deferment is more sensitive to energy storage than input source. • Diverse flexibility options can reduce cost and curtailment by 30–50%. • 40–45% of allowed flexibility used during specific hours of the day. [ABSTRACT FROM AUTHOR]

In modern power system planning and operation, the relevance of distributed power generation units and demand-side flexibility options grows. As a consequence, smart planning and operation routines become necessary also in the distribution grid. We therefore develop a co-optimization framework to consider transmission and distribution system constraints and their interactions together. This enables bidirectional flows between both systems, supporting a consistent and cost-efficient overall energy system. The key feature of this paper is an automated coupling of two independently and modularly defined systems. It allows a bottom-up modelling approach of energy demands, conversion and storage technologies from both system levels. However, this approach increases the model size significantly. Thus, timeseries aggregation methods are applied to reduce the computational complexity. The results for the optimal planning of the coupled German energy system show that the electrification of heat and mobility sectors in the distribution grid is not only beneficial to achieve carbon neutrality in 2050, but also to particularly make use of additional flexibility potentials. Our results underline a significant positive correlation between a smart operation of heat pumps and charging stations with the maximum integrable capacities of low-cost rooftop photovoltaics in the distribution system. • Open-source framework to couple transmission system and active distribution grids. • Co-optimization of both system levels enables a holistic model with a global optimum. • Case study: German energy system with the carbon-neutrality target by 2050. • Electrification of residential heat and mobility sector to unlock flexibilities. • Gained flexibilities promote 20% higher PV capacities and reduce system costs by 7%. [ABSTRACT FROM AUTHOR]

The depletion of fossil fuels and climate change pose huge challenges to sustainable development. How to meet the increasing energy demands in an efficient and environmentally friendly manner has become the focus of attention all around the world. The hybrid combined cooling, heating and power (CCHP) systems that combine fuel powered CCHP systems with high energy efficiency and renewable energy technologies with zero emissions are attractive. Hence, this paper reviews various studies on such systems. Firstly, the possible integration forms of available technologies are summarized, which include combined heating and power systems, waste heat recovery systems, solar energy systems, geothermal energy systems, wind energy systems as well as energy storage systems. Secondly, the different application scenarios such as neighborhood level, district level and city level are summed up. The primary concern at the neighborhood level is whether the allocation of benefits needs to be considered. The core of the district level is how to properly decompose the district into multiple sub-districts. Research on the city level is to provide valuable guidance for the harmonious development of the city. Finally, on the basis of the above review, several perspectives that require further efforts are put forward. • The possible integration methods of available energy technologies are investigated. • The application scenarios of distributed energy systems are detailed in three levels. • Several potential perspectives are proposed based on the current studies. [ABSTRACT FROM AUTHOR]

This paper proposes a novel energy distribution optimization method of hybrid energy storage system (HESS) and its improved semi-active topology for electric vehicles (EVs) to further reduce battery capacity degradation and energy loss. Compared with the traditional HESS semi-active topology, the proposed improved topology reduces the energy loss when the battery charges the supercapacitor (SC) to further enhance the efficiency of the system. The real urban driving data of electric vehicles are collected through experiments and divided into aggressive type, cautious type and standard type according to driving style. Based on the mature multi-mode control (MMC), different weight coefficients are assigned to the two optimization objectives of battery capacity degradation and energy loss based on different driving styles, and gray wolf optimization (GWO) is used to optimize the battery output power upper limit and SC charging upper limit of MMC. The simulation results show that compared with the traditional MMC and semi-active topology, the battery capacity degradation and energy loss are improved under different driving styles. In addition, by further analyzing the simulation results, the research direction of HESS energy distribution strategy in the future is discussed. • An improved semi-active topology of HESS is proposed. • The real urban driving data of EV is taken as the research object and classified according to driving style. • GWO is used to optimize the energy loss and LIB capacity degradation of HESS. • Assign different weights to the two optimization objectives according to different driving styles. [ABSTRACT FROM AUTHOR]

This paper addresses a modular design for the methanol synthesis system driven by renewable energy based on the standardization of production lines, aiming to facilitate the storage and utilization of the renewable energy and promote the sustainability of methanol production. An optimization model for the modular design of methanol production lines was proposed to minimize the total annual cost of the system. The modular design scheme of the system, including the number and capacity configuration of the modular production lines, and the scheduling scheme of the modular production lines, were determined by solving the proposed optimization model. The application of the proposed system and the design method were verified via a case study. The effects of the renewable energy fluctuations and the modularization on the design and operation of the methanol synthesis system were explored with the consideration of the continuity and stable operation requirements. • A modular methanol synthesis system driven by renewable energy is constructed. • A design model for the methanol synthesis by modular production lines is proposed. • The design and operation of the modular methanol production system are determined. • The impacts of fluctuations of renewable energy on the system are explored. • The modular methanol synthesis system shows better economic and operational flexibility. [ABSTRACT FROM AUTHOR]

Small Island Developing States (SIDS) have a high dependency on fossil fuels for energy, water, and food production. This has negative implications on the carbon footprint and resilience of the SIDS. Wind power is one of the most promising options for renewable energy in the coastal areas of the SIDS. To account for the seasonal intermittent nature of wind energy, ammonia can be used for energy storage. In this paper, ammonia as an energy vector, is examined to reduce the costs and carbon footprint of energy on the island of Curaçao as a showcase for Caribbean SIDS. The levelized cost of electricity (LCOE) for the combined wind and ammonia energy storage system is 0.13 USD/kWh at a discount rate of 5%. This is cost competitive with the LCOE of 0.15–0.17 USD/kWh from heavy fuel oil, which is the main electricity source in the Caribbean SIDS. In Curaçao, the LCOE from LNG and coal without carbon capture and storage (CCS) is 0.07–0.10 USD/kWh and 0.09–0.14 USD/kWh, respectively. When CCS is applied, the LCOE from LNG and coal is 0.10–0.13 USD/kWh and 0.14–0.21 USD/kWh, respectively. This suggests that the LCOE of the combined wind and ammonia energy storage system can be competitive with fossil-based alternatives with carbon capture and storage (CCS) in a decarbonized energy landscape. The CO 2 -footprint of the combined wind energy and ammonia energy storage system is 0.03 kg CO 2 /kWh, compared to 0.04 kg CO 2 /kWh and 0.12 kg CO 2 /kWh for LNG-/coal-based energy generation with CCS, respectively. [Display omitted] • Green ammonia seasonal energy storage is feasible in Curaçao (Caribbean SIDS). • Absorption Enhanced Haber-Bosch using Ru-catalysts results in a LCOE of 0.13 USD/kWh. • Wind energy combined with ammonia energy storage leads to a carbon footprint of just 0.03 kg CO 2 /kWh. • Hybrid thermal and membrane processes enable zero-liquid discharge seawater desalination. [ABSTRACT FROM AUTHOR]

The popularity of renewable energy systems has contributed significantly in the last years to the utility of low voltage direct current microgrids. However, these systems come with new challenges. This survey focuses on introducing a state-of-the-art low voltage direct current distribution system and sheds light on the challenges that must be faced in order to complete energy transition. This literature review was systematically carried out using the two largest scientific databases (SCOPUS and WOS) where the query (low voltage direct current microgrid) resulted in 198 articles. The purpose of this paper is not to reiterate the comparison of direct current with alternating current systems, which has already been discussed extensively. Instead, the objective of this survey is to assess the feasibility of the low voltage direct current distribution system and its impact on social development. To this end, this work provides valuable information for renewable energy planners, giving some insights or solutions to bridge the gap between the current energy network and the future DC energy microgrids. In particular, this article focuses on parameters such as grid topologies, distribution and voltage standardization efforts. The three major findings are: (i) the off-grid solutions enhance the efficiency rate in energy facilities (from 15% to 30%), and the vast majority of them are supported with energy storage systems to increase their reliability. However, in economic terms the most suitable systems still are the grid-connected solutions. Another finding is that (ii) the bus configurations are most used as well as the best in terms of their effectiveness to distribute low voltage and direct current energy within the microgrid. Lastly, (iii) the voltage value standardization around 48 V and 380 V, and even though there seems to be a clear convergence between them, the lack of agreement is delaying the massive implementation of these solutions worldwide. Finally, a novel assessment of social impacts and reflections on low voltage direct current microgrids is also included. • A thoughtful survey of low voltage DC microgrids is done. • An assessment of which are the types of standards used for every application is presented. • An analysis about how these sorts of systems impact on social indicators is performed. • A prospective analysis based on the low voltage DC systems is carried out. [ABSTRACT FROM AUTHOR]