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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]

As the development of distributed solar photovoltaics (DSPV), battery energy storage systems are growing in popularity to promote the performance of DSPV, for both mitigating the impact on the grid and increasing the economic performance. In the meantime, reused batteries retired from electric vehicles provide another option for energy storage systems. In this paper, the economic performance evaluated by net present value of DSPV with reused batteries as energy storage systems (RBESS) is studied at the provincial level in China, so as to depict a comprehensive understanding of the current DSPV status and the development potential of RBESS in China. Instead of only focusing on the role of increasing the percentage of self-consumption (Model 1), a combined usage strategy of RBESS (Model 2) is also proposed. Moreover, the residual value of lithium-ion batteries is taken into consideration in this paper. Our results show that for the residential sector, only a small number of areas can benefit from RBESS under Model 2, while none can benefit under Model 1. Only when the price of RBESS decreases to 200 CNY/kWh, the profitability could be nationwide. However, for the commercial and industrial sector, the performance of RBESS is much better. In the majority of areas, integrating RBESS with DSPV is already profitable. • Provincial level analysis is conducted. • Two using strategies of RBESS are presented. • Only when the price of RBESS decreases to 200CNY/kWh, can the positive NPV be nationwide. • The C&I sector outperforms the residential sector in terms of the ability to gain profits from DSPV and RBESS. [ABSTRACT FROM AUTHOR]

Abstract Using different types of renewable energy sources considering their uncertainties causes numerous challenges for minimizing the operation cost and maximizing the reliability of system. Hence, stochastic programming is an essential tool to consider the system uncertainties. This paper presents a day-ahead energy management system to decrease the operation cost and increase the reliability of a Microgrid considering a number of challenges for supporting electrical and thermal loads. In the proposed method, micro-CHP units, renewable energy sources, auxiliary boiler and energy storage system are all responsible for supplying the electrical and thermal loads. The problem is formulated as a multi-objective optimization problem. Moreover, the influence of considering the electrical energy storage system as a non-ideal battery with charge/discharge efficiency less than 1 is investigated. Also, demand response programs are provided based on load shifting contracts to consumers. A scenario-based approach is used to cover the uncertainties of renewable energy sources, market price and electrical load. Besides, this paper considers both islanding and grid-connected modes of Microgrid and investigates the influence of demand side management on operation cost and reliability in both modes. The capability of the proposed algorithm is analyzed by simulation results of a 3-feeder Microgrid. Highlights • Stochastic model is proposed for covering the uncertainties of variables. • The effect of micro-combined heat and power units on operation cost are considered. • The effect of storage system on operation cost and reliability index are considered. • Operation cost and reliability index are considered as objective functions. • Presenting a new mathematical method for implementing direct load control programs. [ABSTRACT FROM AUTHOR]

Abstract To lower the cost of electricity produced, advanced high-efficiency power cycles operating at temperatures above 600 °C (such as the supercritical CO 2 Brayton cycle) are presently being developed for use in both nuclear and concentrating solar power (CSP) plants. Incorporating thermal energy storage into CSP plants allows renewable energy to be generated while simultaneously providing reliability and stability to the grid. Sensible energy storage using molten nitrate salts is used in the majority of CSP plants. However, nitrate salts decompose at around 600 °C, hence an alternative storage medium is required to support the development of next generation high-efficiency CSP plants. Because of practical experience with molten salt storage in the two-tank configuration in industry, continuing to use fluid media is an attractive option, although thermal storage is also possible with other types of storage media (e.g. solids and phase change materials). This paper critically reviews options for energy storage in fluids that are stable over 600 °C. The focus is on three alternative molten salts — fluorides, chlorides and carbonates — which are assessed based on their thermophysical properties and cost. A brief review of liquid metal and molten glass storage options is included for completeness. Corrosion of containment materials is an important consideration in the choice of storage media, because if exotic materials are required, the cost of the storage tanks can dominate the overall storage cost. Therefore, this paper includes a summary of the main corrosion issues relating to containment of the more promising storage fluids considered herein, identifying possible tank materials and corrosion mitigation options. Graphical abstract fx1 Highlights • Storage media stable at > 600 °C are needed for advanced concentrating solar plants. • Carbonate, chloride and fluoride molten salt mixtures are the main candidates. • Carbonate and fluoride salts have attractive specific heat capacity but high cost. • Corrosion is a major challenge for all three salts, particularly for fluoride salts. • Research trends favour chlorides due to low cost and suitable thermal properties. [ABSTRACT FROM AUTHOR]

Abstract Along with the advent of restructuring in power systems, considerable integration of renewable energy resources has motivated the transition of traditional distribution networks (DNs) toward new active ones. In the meanwhile, rapid technology advances have provided great potentials for future bulk utilization of generation units as well as the energy storage (ES) systems in the distribution section. This paper aims to present a comprehensive review of recent advancements in the operation of active distribution systems (ADSs) from the viewpoint of operational time-hierarchy. To be more specific, this time-hierarchy consists of two stages, and at the first stage of this time-hierarchy, four major economic factors, by which the operation of traditional passive DNs is evolved to new active DNs, are described. Then the second stage of the time-hierarchy refers to technical management and power quality correction of ADSs in terms of static, dynamic and transient periods. In the end, some required modeling and control developments for the optimal operation of ADSs are discussed. As opposed to previous review papers, potential applications of devices in the ADS are investigated considering their operational time-intervals. Since some of the compensating devices, storage units and generating sources may have different applications regarding the time scale of their utilization, this paper considers real scenario system operations in which components of the network are firstly scheduled for the specified period ahead; then their deviations of operating status from reference points are modified during three time-intervals covering static, dynamic and transient periods. Highlights • A survey of operational methods of active distribution systems (ADSs) is presented. • A two-stage time-hierarchy methodology is adopted to categorize recent research. • Day-ahead economic management of ADSs is explored in the first stage. • Static, dynamic and transient operations of ADSs are studied in the second stage. • Modeling and control needs of ADS economic/technical operation are reviewed. [ABSTRACT FROM AUTHOR]

Abstract The demand for reduction of greenhouse gases, the need for a decreased dependence on fossil fuel, and the increasing penetration of the renewable energy sources are changing the world's electrical energy production. The island of Crete in Greece possesses great potential when it comes to wind and solar energy. Currently, a large amount of wind energy is often being curtailed in Crete, due to the technical minima of the existing thermal units, the inherent fluctuating power output of the wind turbines and the electricity demand profile. Electrical energy storage is recognized as an underpinning technology to have great potential in overcoming these challenges. There are many different ways to store the surplus energy and convert it back to electrical energy when it is needed. The aim of the present paper is the investigation of the role that energy storage can play in the further development of renewable energy sources in non-interconnected islands via considering the energy storage technologies of compressed air energy storage, pumped hydroelectric storage and sodium – sulfur batteries. This paper examines the solution of electrical energy storage in curtailment exploitation. A review over the above energy storage technologies is carried out and a comparative analysis is performed for the case study of Crete. Each storage technology is techno-economically evaluated using actual data. Finally, a parallel comparison of the examined storage systems' levelized cost of energy is presented and conclusions are drawn. The compressed air energy storage system appears to be more favorable, having the lowest levelized cost of energy of the examined systems studied at 0.21 €/kWh, while contributing 105.59 GWh of electrical energy to the island's grid per year. For the examined case study, compressed air energy storage system appears to be almost 20% and 50% cheaper in terms of levelized cost of energy in comparison with pumped hydro storage and batteries respectively. Highlights • Review on compressed air energy storage, pumped hydroelectric storage and sodium – sulfur batteries. • Techno-economic comparative analysis of energy storage technologies for the case study of Crete. • Comparative findings on levelized cost of energy of different storage technologies. [ABSTRACT FROM AUTHOR]

Abstract In recent years, providing green and reliable energy supply to islands has appeared in the strategic plans of many countries. This paper introduces three representative island microgrids that have been built and are operating in the East China Sea. Key technologies of the island microgrids are discussed, including the analysis of island resources and load, selection of energy storage, control strategies, and energy management systems. Through analyzing their operation data for one year, this paper demonstrates the impacts of the three microgrids from the perspectives of technology, economics, and sustainability. Summarizing the experiences and insights gained from their construction and operation, this paper provides references for the future development of island microgrid projects. Highlights • Three representative island microgrids in the East China Sea are demonstrated. • Key technologies such as control technology and energy management for island microgrids are studied. • Renewable energy penetration is discussed for the design and operation of island microgrids. • The operation data for a year of the three island microgrids are analyzed from various aspects. • Experiences and insights gained from the construction and operation are presented. [ABSTRACT FROM AUTHOR]

Latent heat storage (LHS) is considered as the most promising technique for thermal energy storage, due to its high energy storage density and nearly constant working temperature. However, the lower thermal conductivity of the phase change material (PCM) used in LHS system seriously weakens thermal energy charging and discharging rates. In order to improve the thermal performance of LHS system, a lot of research on performance enhancement have been carried out. This review paper will concern on the development of PCMs and performance enhancement methods for LHS system in the last decade. The available enhancement methods can be classified into three categories: using high thermal conductivity additives and porous media to enhance PCM thermal conductivity, using finned tubes and encapsulated PCMs to extend heat transfer surface, using multistage or cascaded LHS technique and thermodynamic optimization to improving the heat transfer uniformity. The comparative reviews on PCMs, corresponding performance enhancement methods and their characteristics are presented in present paper. That will help in selecting reliable PCMs and matching suitable performance enhancement method to achieve the best thermal performance for PCM based LHS system. In addition, the research gaps in performance enhancement techniques for LHS systems are also discussed and some recommendations for future research are proposed. [ABSTRACT FROM AUTHOR]

Electrical energy becomes necessary for human being. Generation of electrical energy mostly depends on fossils fuel, they are limited in nature and also responsible for environmental pollution. Renewable energy resources provides a better alternative for future,In comparison to conventional energy resources economical aspect is a major issue of renewable energy sources with the feasibility and efficiency. These limitations are tried to overcome by deployment hybrid renewable energy resources. There are certain criteria to analyze and implement the sized, optimized and cost efficient system. This paper focus on hybrid energy systems based on solar photovoltaic (PV) and wind resources. This paper shed lights on various parameters of economic feasibility, sizing strategies with logical advancements to enhance their utilization, future prospects, and their arrangement. Strategies to develop an effective storage system is also presented here.A brief review on developments in optimization techniques, reliability index and cost analyzing techniques for hybrid renewable energy systems are also presented. [ABSTRACT FROM AUTHOR]

The development of cleaner and renewable energy sources are necessary so that fossil fuel dependency and global warming can be reduced. Present communication is an attempt to explore the available literature on Photovoltaic Thermal (PVT) air collectors and PVT air collector integrated greenhouse drying system. Solar drying is one of the best method to preserve crops for a long time. In developing and under developed countries; per capita electricity production is low; therefore the electricity uses for heating purpose cannot be economically and environmentally justified option. In previous studies, it was found that forced drying is better in terms of controlling drying parameters and PVT air collector is better than standalone PV module in terms of energy storage. In present review paper, combination of PVT air collector and drying system has been discussed. Moreover, thermal modelling of PVT air collector integrated greenhouse drying system has been presented in detail. Average thermal efficiency, electrical efficiency and overall thermal efficiency for PVT air collector are found to be 26.68%, 11.26% and 56.30% respectively at 0.01 kg/s mass flow rate of air. This review paper may be very helpful for researchers and scientists to develop thermal models for different hybrid solar systems. [ABSTRACT FROM AUTHOR]

To maximize the introduction of renewable energy, introducing grid energy storage systems are essential. Electrochemical energy storage system, i.e., battery system, exhibits high potential for grid energy storage application. A battery energy storage system is comprised of a battery module and a power conversion module. This paper starts by reviewing several potential battery systems, as well as an advanced aluminum-ion battery that currently has promising prospects in the electrochemical energy storage system. The characteristics of the batteries are reviewed and compared, including the materials, electrochemistry, performance and costs. The application prospect of the batteries is discussed. The paper summarizes the features of current and future grid energy storage battery, lists the advantages and disadvantages of different types of batteries, and points out that the performance and capacity of large-scale battery energy storage system depend on battery and power condition system (PCS). The power conversion system determines the operational condition of the entire energy storage system. The new generation wide bandgap semiconductor for power electronic technology is discussed from the perspective of performance, topology, model and non-linearity and is compared to the traditional silicon-based semiconductor. Finally, the application prospect of the new generation semiconductor technology in the energy storage system is indicated. This paper concludes the application status of the energy storage system in the renewable energy power generation and indicates the critical problems that need to be addressed during the construction and operation of the storage system. [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]

Energy demands, environmental impacts of energy conversion, and the depletion of fossil fuels are constant topics of discussion in the energy industry. Renewable energy technologies have been proposed for many years to address these concerns. However, the transformation from traditional methods of power generation, usually based on fossil fuels, to power generation based on renewable resources presents many challenges associated with emerging, or less established, technologies. This paper examines the role of renewable energy in the U.S. and its potential to meet current and future energy needs in a way that is technically and economically sound. Renewable energy technologies, ranging from well-developed and established to new and emerging technologies, are presented in terms of their technical potential, current state of the technology, potential for further growth, and economic potential. While renewable energy sources are abundant across the U.S., issues of dispatchability, variability, scalability, energy storage, geographic limitations, and investment costs are critical in determining future progress. The analysis in this paper can be used to guide the integration of renewable energy systems toward becoming a larger share of energy production. [ABSTRACT FROM AUTHOR]

Geo-resources play an increasing significant role in achieving a sustainable energy future. However, their exploitation is not free of environmental impacts. This paper aims to identify the lessons and knowledge gaps on understanding of the sources, mechanisms and scope of environmental consequences of underground geo-energy resources exploitation. The paper examines four underground exploitation activities: CO 2 geological storage, exploitation of shale gas, geothermal power and compressed air energy storage (CAES). Selected studies carrying out life cycle assessment (LCA) and environmental risk assessment (ERA) are structurally reviewed by applying a six steps method. Our finding indicates that global warming potential is the major focus of examined LCA studies with relatively less attention on other impacts. Environmental impacts at the local level are less evaluated except water use for shale gas and geothermal power. Environmental impacts of exploitation with storage purposes are relatively low. For energy supply associated exploitation, the impacts largely depend on the types of underground activities and the exploited energy carriers. In the ERA studies, likelihood of a hazard occurrence is the focus of the probability assessment. There is limited information on the pathways and transport of hazard agents in the subsurface and on the relation between hazard exposure and the impacts. The leakage of the storing agents is the well-identified hazard for storage associated exploitation, while the migration of fluids and exploited energy carriers are the ones for exploitation with energy supply purposes. In general, understanding of environmental risks of soil contamination are limited. Very few number of ERA studies are available for assessing a CAES. Our research points out the need for developing a framework which allows the integration between LCA and ERA in subsurface environmental management. [ABSTRACT FROM AUTHOR]

Over the past few decades, many publications have been made in the area of Load frequency control (LFC) of interconnected power systems. Load frequency control is necessary to develop better control in order to achieve less effect on the frequency and tie line power deviations after a load perturbation. However, number of control strategies has been employed in the design of load frequency controllers in order to achieve a better dynamic response and the exact choice of the LFC controller in a particular case requires sufficient expertise because each controller has its own merits and demerits. Due to this, an appropriate review of load frequency control (LFC) mechanism is essential and a few attempts have been made in this concern. This paper presents a detailed survey on load frequency control (LFC) mechanism. The overall study explores the depth study issues related to LFC mechanism based on different sources of power system models. This paper focused on different control techniques of LFC, which also includes all the recent application of FACTS devices. This review reveals the investigation of soft computing based optimization technique and application of Energy Storage System (ESS) and HVDC-link in LFC. These studies also illustrates conventional power system, deregulated of power environment as well as distributed generation and micro grids. This paper is designed in order to highlight the major traits of Load forecasting and some critical case studies on LFC. [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]

The intuition of the power distribution system is to supply good quality of power to the customers with cost-effectively and environment friendly. Renewable energy resources (RES) are integrated in the distribution system to meet out the variable load demand with the decarbonizing effect. With the inclusion of RES, the operation of Distribution Network (DN) has become more complex. This paper describes the state of art in various load flow methods used to analyze the parameters in DN. This paper emphasizes upon the various challenges of DN with the integration of RES. It reviews the various pricing methodologies for the delivered power in DN elaborately. The importance of Demand Side Management (DSM) and energy storage in DN are explored in this paper. The analysis of nodal voltages in the DN with Solar PV, Storage, PHEV and Diesel sources is demonstrated on IEEE four node test feeder. [ABSTRACT FROM AUTHOR]

In this paper, an extensive literature survey on critical research areas of various load frequency control (LFC) methods in a deregulated power system with conventional and distributed power generators are emphasized. The main goal of LFC is to ensure zero steady state error for frequency and tie-line power deviations. This paper provides an overview of different types of deregulated power system structures, market models, contracts agreements and various control methodologies/techniques for mitigating the various LFC issues in a deregulated power system. Detailed analysis of various control methodologies based on classical control, robust and self tuning control and various soft computing control techniques are discussed. Finally, the investigations on incorporating fast acting energy storage devices such as Battery energy storage system (BESS), superconducting magnetic energy storage (SMES), Redox flow batteries (RFB) and Flexible AC transmission systems (FACTS) devices for mitigating the LFC problems in a deregulated power system are also addressed. [ABSTRACT FROM AUTHOR]

With the global environmental pollution and fossil energy shortage problems getting increasingly serious, renewable energy sources (RES) are drawing more and more attention. In China, RES are experiencing rapid development. However, because of the randomness of RES and the volatility of power output, energy storage technology is needed to chip peak off and fill valley up, promoting RES utilization and economic performance. So to speak, energy storage is the precondition of large-scale integration and consumption of RES. However, China's energy storage industry is at the exploration stage and far from commercialization. This restricts the development of RES to certain extent. For this reason, this paper will concentrate on China's energy storage industry. First, it summarizes the developing status of energy storage industry in China. Then, this paper analyzes the existing problems of China's energy storage industry from the aspects of technical costs, standard system, benefit evaluation and related policies. Finally, solutions are proposed based on the above problems to promote the sound development of China's energy storage industry. [ABSTRACT FROM AUTHOR]

Unit Commitment (UC) is an optimization problem used to determine the operation schedule of the generating units at every hour interval with varying loads and generations under different generational, environmental and technical constraints. With the significant increase of Renewable Energy Sources (RES) integration into the power networks, effects posed by these system changes to the UC are actively being studied and investigated by global researchers and operation engineers. To this end, this paper firstly provides a literature survey of UC concept, objectives and constraints. Different UC models developed for addressing RES impacts are also reviewed. Moreover, many algorithms have been proposed in the past few decades to optimize the UC problem. This work explores the necessity for alternative optimization approaches for UC solution. In doing that, the work uncovers the advantages and disadvantages of the existing methodologies so that future algorithms could be designed in retaining the advantages of the existing methodologies while avoiding the presented weaknesses. In addition, installation of energy storage devices to balance the fluctuation in power generation and their associated impacts on UC models are reviewed. The contents of this paper provide ready-to-refer and ready-to-use information for the researchers working in the field of UC. [ABSTRACT FROM AUTHOR]

The fast charger for electric vehicle (EV) is a complex system that incorporates numerous interconnected subsystems. The interactions among these subsystems require a holistic understanding of the system architecture, control, power electronics, and their overall interaction with the electrical grid system. This review paper presents important aspects of a PV-grid integrated dc fast charger—with a special focus on the charging system components, architecture, operational modes, and control. These include the interaction between the PV power source, grid electricity, energy storage unit (ESU) and power electronics for the chargers. A considerable amount of discussion is also dedicated to battery management systems (BMS) and their mutual interactions in the control processes. For the power electronics, the paper evaluates soft switching non-isolated dc-to-dc power converter topologies that can be possibly used as future EV chargers. In addition to these, a brief discussion on the impact of the PV-grid charging on the ac grid and distribution system and their remedial measures are presented. Furthermore, the challenges in regard to the vehicle to grid (V2G) concept are also described. It is envisaged that the information provided in this paper would be useful as a one-stop document for engineers, researchers and others who require information related to the dc fast charging of EV that incorporates a renewable energy source. [ABSTRACT FROM AUTHOR]

The electric vehicle (EV) technology addresses the issue of the reduction of carbon and greenhouse gas emissions. The concept of EVs focuses on the utilization of alternative energy resources. However, EV systems currently face challenges in energy storage systems (ESSs) with regard to their safety, size, cost, and overall management issues. In addition, hybridization of ESSs with advanced power electronic technologies has a significant influence on optimal power utilization to lead advanced EV technologies. This paper comprehensively reviews technologies of ESSs, its classifications, characteristics, constructions, electricity conversion, and evaluation processes with advantages and disadvantages for EV applications. Moreover, this paper discusses various classifications of ESS according to their energy formations, composition materials, and techniques on average power delivery over its capacity and overall efficiencies exhibited within their life expectancies. The rigorous review indicates that existing technologies for ESS can be used for EVs, but the optimum use of ESSs for efficient EV energy storage applications has not yet been achieved. This review highlights many factors, challenges, and problems for sustainable development of ESS technologies in next-generation EV applications. Thus, this review will widen the effort toward the development of economic and efficient ESSs with a longer lifetime for future EV uses. [ABSTRACT FROM AUTHOR]

The energy storage system (ESS) in a conventional stand-alone renewable energy power system (REPS) usually has a short lifespan mainly due to irregular output of renewable energy sources. In certain systems, the ESS is oversized to reduce the stress level and to meet the intermittent peak power demand. A hybrid energy storage system (HESS) is a better solution in terms of durability, practicality and cost-effectiveness for the overall system implementation. The structure and the common issues of stand-alone REPS with ESS are discussed in this paper. This paper presents different structures of stand-alone REPS with HESS such as passive, semi-active, and active HESS. As there are a variety of energy storage technologies available in the market, decision matrixes are introduced in this paper to evaluate the technical and economic characteristics of the energy storage technologies based on the requirements of stand-alone REPS. A detailed review of the state-of-the-art control strategies such as classical control strategies and intelligent control strategies for REPS with HESS are highlighted. The future trends for REPS with HESS combination and control strategies are also discussed. [ABSTRACT FROM AUTHOR]

This paper proposes a thermally compensated electrolyser model coupled with a Pressurised Hydrogen Storage model for modelling Renewable Hydrogen Energy Storage Systems needed to support the uptake of renewable energy sources (RES) integration into the grid. The model accurately simulates the output of real world electrolyser and hydrogen storage installations and can be used as a tool for assessing their integrity with intermittent RES. The model, which has been developed using Matlab/Simulink, incorporates a set of thermally compensated simulation equations to emulate the real world operating installations and define their hydrogen production under different energy configurations (grid connected or directly connected to the RES). It can also be used to determine the efficiency of an electrolyser under cold start or during full temperature operation. The proposed model has proved its ability to emulate real world hydrogen energy systems, and this has been validated by comparing its output to the real-world data logged from an existing field installation. The developed model has also been used as a tool to assess the performance of an operating real world system, installed in Africa, and which has not been performing as anticipated. Simulation results revealed the presence of a hydrogen leak within this infield installation, and this has been confirmed by an onsite inspection. The developed model has therefore also proved to be able to examine the performance of operating real-world hydrogen energy systems and detect irregularities and operation performance issues. In summary, this paper proposes a Hydrogen Energy Storage system (HES) model as an enabler simulation tool to support the projected increase of renewable integration into the grid. The model also allows the detection of performance issues within operating HES systems and allows the identification of leaks without the need for conducting intrusive inspections of the installations, hence saving money and time. [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]

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]

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]

In this paper, the authors investigate four original methodologies for sizing a battery bank inside a passive wind turbine system. This device interacts with wind and load cycles, especially for a stand-alone application. Generally, actual wind speed measurements are of long duration which leads to extensive processing time in a global optimization context requiring a wide number of system simulations. The first part of this article outlines two sizing methodologies based on a statistical approach for the sizing of the electrochemical storage device of a stand-alone passive wind turbine system. Two other efficient methodologies based on the synthesis of compact wind speed profiles by means of evolutionary algorithms are described in the second part of this paper. The results are finally discussed with regard to the relevance of the battery bank sizing and in terms of computation cost, this later issue being crucial to an Integrated Optimal Design (IOD) process. [ABSTRACT FROM AUTHOR]

Renewable energy sources have a huge potential to reduce greenhouse gas emissions and decrease the dependence on fossil fuels in the energy sector. However, the energy output of these sources is variable and raises concerns regarding the electric grid reliability. Therefore, the deployment of energy storage would play a key role in enabling the integration of these sources in the electric grid. This paper proposes methods for determining the optimal operation and sizing of energy storage systems. The main purpose of the operation strategy is to maximize the revenues of the renewable farm. The sizing model, on the other hand, has a purpose to minimize the cost of the hybrid system while meeting the service requirement. Both methods were formulated as non-linear programming optimization models. To verify the effectiveness of these methods; case studies have been presented. Finally, this paper proposes an economical analysis to determine the cost added by the storage to each KWh of stored energy. [ABSTRACT FROM AUTHOR]

Photogalvanic cells are based on the photogalvanic effect; provide an additional method on acquiring energy, converting sunlight into electricity and its storage. Production of potential between two electrodes separated by suitable substances in which the influence of light on the electrode potential is due to a photochemical process in the body of the electrolyte is termed as the Becquerel effect so called photogalvanic effect. In this review we have proposed suitable classification of solar cell based on the excitation (direct or indirect) of electron and semiconductor used, in which the photogalvanic cell has potential to revolutionize the existing solar cells due to its low cost and inherent storage capacity. Various type of photogalvanic effect has been discussed as linear photogalvanic, circular photogalvanic and photogalvanomagnetic effect. The main purpose of the paper is to review the results of research published related to this phenomenon and to propose the mechanism for the photocurrent generation in detail. Here, we have reviewed around 400 research articles/patents/reports/proceedings in the development of photogalvanic cells, from early stage to recently more efficient; considering electrolyte, electrode material and assembly set up. The results of electrical parameters (open circuit potential, short circuit current, power at power point, fill factor, conversion efficiency and storage capacity) of the photogalvanic cells containing dye, reductant and surfactants have given in a tabular form with comparison of more than 150 systems. A vast collection of photogalvanic systems and their electrical parameters have been scrutinized for further research work to enhance the electrical output and to make it commercially viable. In this paper, the primitive photogalvanic systems with iron–thionine to recent dye–reductant–surfactant system with specific reference to chronological and technological development in the cell have been discussed. We have also focused on the challenges and limitations in the field of photochemical conversion of solar energy and its storage. [ABSTRACT FROM AUTHOR]

Renewable Energy Sources (RESs) particularly photovoltaic (PV) and wind are becoming important sources for power generation. Frequently varying output of PV and wind caused by clouds movement, weather condition and wind speed make them an intermittent and unreliable sources when connected to grid. Connecting intermittent sources to grid introduces challenges in various technical aspects such as power quality, protection, generation dispatch control and reliability. In this context , leveling intermittent source׳s output is necessary inorder to maintain grid׳s stability. This paper is aimed at bringing out the latest comprehensive literature review on problems associated when the intermittent PV is connected to grid and the methods of smoothing the output power fluctuation from PV. This paper also briefly discusses control strategy built for battery energy storage pertaining to this issue. [ABSTRACT FROM AUTHOR]

For isolated power networks supplied by intermittent energy sources, several doubts have emerged regarding the impact of the uncertainties on the networks reliability. This paper performs optimal sizing for a hybrid power system with wind/energy storage sources based on stochastic modeling of historical wind speed and load demand. The autoregressive moving average is used to stochastically model the uncertainty of the load demand/wind speed and, the sequential Monte Carlo simulation is performed to chronologically sample the system states. The contribution of the paper can be summarized as follows: (1) an objective function based on self-adapted evolutionary strategy in combination with the Fischer–Burmeister algorithm is proposed to minimize the one-time investment and annual operational costs of the wind/energy storage sources; and (2) the effect of the cycle efficiency and charging/discharging rate of different energy storage units on the system cost is investigated under different reliability and load shifting levels. The computational performance of the proposed optimization solver is proven in order to obtain the minimum possible investment cost. The presented case studies in this paper provide the decision makers with the flexibility to choose the suitable capacity installation at different values of reliability and load shifting levels. [ABSTRACT FROM AUTHOR]

Energy storage (ES) is an important device to ensure operation stability and efficiency of a renewable energy based distributed energy generation (DEG) system. As such, many researchers have modelled the operation (scheduling) of energy storage in a DEG system, where it is mostly portrayed to operate on a daily cycle. In this paper, an analysis of the operation mode of energy storage is presented. Two modes of operation are defined, daily mode (DM) (ES operates in daily cycles) and weekly mode (WM) (ES operates in weekly cycles) which are modelled accordingly. This paper then attempts to analyse and compare between both modes in term of operation and cost. The analysis is performed through a mixed integer linear programming (MILP) model programmed via the General Algebraic Modelling System (GAMS). In general, with high capital cost of ES, it is advisable to program the ES to operate in a DM. The reason to this conclusion is mainly due to three factors, intermittency of renewable resources, varying weather conditions, and discharge rate of ES(s). [ABSTRACT FROM AUTHOR]

Uninterruptible Power Supplies (UPS) have reached a mature level by providing clean and uninterruptible power to the sensitive loads in all grid conditions. Generally UPS system provides regulated sinusoidal output voltage, with low total harmonics distortion (THD), and high input power factor irrespective of the changes in the grid voltage. This paper provides comprehensive review of UPS topologies, circuit configurations, and different control techniques used in the UPS system. A comparison based on the performance, size, cost, and efficiency of the system is presented. Different hybrid energy source UPS system and new generation UPS system for smart grid and micro-grid has been explained. Finally the paper describes performance evaluation of UPS system and explains different aspects that are to be considered for choosing a suitable UPS system by the user. [ABSTRACT FROM AUTHOR]

Electric energy transport theories are still a debatable subject regarding their validity and applicability in various aspects. This paper includes a comparative study of the group of theories which are categorized as instantaneous theories as opposed to periodic-averaged ones. As a preliminary review this paper presents first the three apparent power definitions in order to emphasize the difference between them. A discussion regarding their accuracy for energy metering of various conditions such as multiphase and non-sinusoidal environments is presented. Instantaneous theories are then reviewed and compared with periodic averaged theories. The review focuses mainly on p-q theory ( PQT ) and its derivative, instantaneous multi-phase theory. The legacy application of this theory for active filtering is briefly presented and the new idea of using the theory for multi-load and multi-source theory is presented as well. The comparison identifies the similarities and differences between the instantaneous and periodic averaging theories, and their inter-relations. [ABSTRACT FROM AUTHOR]

Wind energy is an abundant source of the pollution free energy. The conventional fossil fuels such as coal, oil and gas are exhausting day by day and wind energy can be the alternative of fossil fuels. Wind energy conversion systems (WECSs) are very vulnerable to the disturbances, faults and low grid voltages. Therefore, modern WECSs are required and designed to the low voltage ride through (LVRT) capability in the line fault condition. There are several approaches to maintain the grid code requirements in the line fault condition. The aim of the paper is to overview some popular approaches of the LVRT capability enhancement in the line fault condition. The fault protection schemes are analyzed using different types of WECSs. The advantages and disadvantages are also analyzed in this paper. To protect the WECSs during the line fault condition, energy storage based approaches are proposed in many literatures but these approaches require an additional system cost. Therefore, some control approaches are proposed for the LVRT capability in literatures without energy storage system which can be reduced the system cost significantly. Among various types of control approaches, in recent, the chopper circuit based fault protection method is gaining interest for the simplicity and fault protection capability without energy storage system. [ABSTRACT FROM AUTHOR]

The application of renewable energy such as solar photovoltaic (PV), wind and fuel cells is becoming increasingly popular because of the environmental awareness and advances in technology coupled with decreasing manufacturing cost. Power electronic converters are usually used to convert the power from the renewable sources to match the load demand and grid requirement to improve the dynamic and steady-state characteristics of these green generation systems, to provide the maximum power point tracking (MPPT) control, and to integrate the energy storage system to solve the challenge of the intermittent nature of the renewable energy and the unpredictability of the load demand. In order to improve the efficiency and the power density of the overall circuit, the use of a three-port DC–DC converter, which includes a DC input port for the renewable source, a bidirectional DC input port for the energy storage system, and a DC output port for supplying the load, is a preferable solution to the traditional method using two DC–DC converters: one for the renewable sources and another for the energy storage system. In recent years, many DC–DC three-port converters have been proposed and reported in the literature. Each of these converters has its own topology and operating principle, which results in different complexities, different numbers of components, different reliability and efficiency. In this paper, a comparison of the features of different topologies of three-port DC–DC converters that have been proposed by different research groups is reviewed briefly. This review can be used as a guide for the appropriate selection of the suitable topology to meet the particular requirement of a system. The paper also discusses the potential research extension of the topologies from three-port DC–DC converters to three-port DC–AC inverters and how the voltage gain of the non-isolated three-port DC–DC converter can be improved. [ABSTRACT FROM AUTHOR]

With good energy storage characteristics, lithium-ion battery electrodes become promising nano-energy storage systems for renewable energy vehicles. However, during the charging and discharging of an electrode system, deformation and degradation may occur, causing battery and material failure that seriously affect the cycling performance and service life of a battery. This is a challenge for the application of lithium batteries in the electric vehicle field. This paper describes the nano-energy system models of different electrode structures and the failure characterization mechanisms during the process of charging and discharging. Moreover, it reviews the new development in the cycling performance evolution and experiment theory, and it analyzes the new research results of Si–C electrode failure. Additionally, this paper addresses the low utilization rate, poor cycling performance and low energy capacity problems associated with lithium batteries. Furthermore, it discusses the highlights, challenges and future direction of lithium batteries and the optimal design technologies that are providing support for the research of lithium battery technologies and development in the energy storage industry. It also reveals the energy system model, nanoscale defects of evolution rules and performance degradation mechanisms according to the failure characterization of nano-structures. Finally, it evaluates the operating mechanism, failure process and engineering application of silicon–carbon–lithium electrode systems. [ABSTRACT FROM AUTHOR]

Introduction of renewable energy sources (RES) in insular areas is growing on different islands of various regions in the world and the large-scale deployment of renewables in island power systems is appealing to local attention of grid operators as a method to decrease fossil fuel consumption. Planning a grid based on renewable power plants (RPP) presents serious challenges to the normal operation of a power system, precisely on voltage and frequency stability. Despite of its inherent problems, there is a consensus that in near future the RES could supply most of local needs without depending exclusively on fossil fuels. In previous grid code compliance, wind turbines did not required services to support grid operation. Thus, in order to shift to large-scale integration of renewables, the insular grid code ought to incorporate a new set of requirements with the intention of regulating the inclusion of these services. Hence, this paper discusses grid code requirements for large-scale integration of renewables in an island context, as a new contribution to earlier studies. The current trends on grid code formulation, towards an improved integration of distributed renewable resources in island power systems, are addressed. The paper also discusses advanced grid code requirement concepts such as virtual wind inertia and synthetic inertia for improving regulation capability of wind farms and the application of energy storage systems (EES) for enhancing renewable generation integration. Finally, a comparative analysis of insular grid code compliance to these requirements is presented in the European context. [ABSTRACT FROM AUTHOR]

Renewable lithium batteries are widely used in both hybrid and pure electric vehicles. Graded materials have structural heterogeneity and anisotropy which allows for these materials to have excellent energy storage capabilities. These important capabilities are why these materials are so fundamental in search for safe, renewable energy storage. As the development of graded materials used in battery development has increased rapidly, the effect of degradation on these batteries has emerged as an issue of international concern. In academic settings specifically, research efforts are focused equally on the capacity degradation of lithium batteries and the security of energy storage. This paper will describe recent advancements in understanding lithium battery performance degradation. To accomplish this goal, this paper will include theoretical characterization models and microscale experimental techniques. In the section that outlines our laboratory work, the impact of coupled degradation effect on the safety of lithium battery is highlighted. The theoretical and experimental analysis section will show that the relationship between degradation (such as dislocations, holes and pores) and energy storage safety is reflected so as to deepen the understanding of the issue’s nature. By discussing battery security and predicting battery performance, this paper evaluates the impact of battery degradation and the corresponding control strategies, offering scientific basis and technical support for the development of sustainable energy. [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]