The need for grid-connected energy storage systems will grow worldwide in the next future due to the expansion of intermittent renewable energy sources and the inherent request for services of power quality and energy management. Electrochemical storage systems will be a solution of choice in many applications because of their localization flexibility, efficiency, scalability, and other appealing features. Among them redox flow batteries (RFBs) exhibit very high potential for several reasons, including power/energy independent sizing, high efficiency, room temperature operation, and extremely long charge/discharge cycle life. RFB technologies make use of different metal ion couples as reacting species. The best-researched and already commercially exploited types are all-vanadium redox batteries, but several research programs on other redox couples are underway in a number of countries. These programs aim at achieving major improvements resulting in more compact and cheaper systems, which can take the technology to a real breakthrough in stationary grid-connected applications.

Redox flow batteries for the storage of renewable energy: A review

Superconducting magnetic energy storage (SMES) is known to be a very good energy storage device. This article provides an overview and potential applications of the SMES technology in electrical power and energy systems. SMES is categorized into three main groups depending on its power conditioning system, namely, the thyristor-based SMES, voltage-source- converter-based SMES, and current-source-converter-based SMES. An extensive bibliography is presented on the applications of these three types of SMES. Also, a comparison is made among these three types of SMES. This study provides a basic guideline to investigate further technological development and new applications of SMES, and thus benefits the readers, researchers, engineers, and academicians who deal with the research works in the area of SMES.

/pdf/an-overview-of-smes-applications-in-power-and-energy-systems-168707qbsk.pdf

An Overview of SMES Applications in Power and Energy Systems

A microgrid (MG) is a local entity that consists of distributed energy resources (DERs) to achieve local power reliability and sustainable energy utilization. The MG concept or renewable energy technologies integrated with energy storage systems (ESS) have gained increasing interest and popularity because it can store energy at off-peak hours and supply energy at peak hours. However, existing ESS technology faces challenges in storing energy due to various issues, such as charging/discharging, safety, reliability, size, cost, life cycle, and overall management. Thus, an advanced ESS is required with regard to capacity, protection, control interface, energy management, and characteristics to enhance the performance of ESS in MG applications. This paper comprehensively reviews the types of ESS technologies, ESS structures along with their configurations, classifications, features, energy conversion, and evaluation process. Moreover, details on the advantages and disadvantages of ESS in MG applications have been analyzed based on the process of energy formations, material selection, power transfer mechanism, capacity, efficiency, and cycle period. Existing reviews critically demonstrate the current technologies for ESS in MG applications. However, the optimum management of ESSs for efficient MG operation remains a challenge in modern power system networks. This review also highlights the key factors, issues, and challenges with possible recommendations for the further development of ESS in future MG applications. All the highlighted insights of this review significantly contribute to the increasing effort toward the development of a cost-effective and efficient ESS model with a prolonged life cycle for sustainable MG implementation.

/pdf/review-of-energy-storage-system-technologies-in-microgrid-13f9i4hnhx.pdf

Review of Energy Storage System Technologies in Microgrid Applications: Issues and Challenges

Energy storages introduce many advantages such as balancing generation and demand, power quality improvement, smoothing the renewable resource’s intermittency, and enabling ancillary services like frequency and voltage regulation in microgrid (MG) operation. Hybrid energy storage systems (HESSs) characterized by coupling of two or more energy storage technologies are emerged as a solution to achieve the desired performance by combining the appropriate features of different technologies. A single ESS technology cannot fulfill the desired operation due to its limited capability and potency in terms of lifespan, cost, energy and power density, and dynamic response. Hence, different configurations of HESSs considering storage type, interface, control method, and the provided service have been proposed in the literature. This paper comprehensively reviews the state of the art of HESSs system for MG applications and presents a general outlook of developing HESS industry. Important aspects of HESS utilization in MGs including capacity sizing methods, power converter topologies for HESS interface, architecture, controlling, and energy management of HESS in MGs are reviewed and classified. An economic analysis along with design methodology is also included to point out the HESS from investor and distribution systems engineers view. Regarding literature review and available shortcomings, future trends of HESS in MGs are proposed.

Hybrid energy storage system for microgrids applications: A review

Renewable Energy Sources have been growing rapidly over the last few years. The spreading of renewables has become stronger due to the increased air pollution, which is largely believed to be irreversible for the environment. On the other hand, the penetration of renewable energy technologies causes major problems to the stability of the grid. Along with the fluctuations of the renewable energy technologies production, storage is important for power and voltage smoothing. Energy storage is also important for energy management, frequency regulation, peak shaving, load leveling, seasonal storage and standby generation during a fault. Thus, storage technologies have gained an increased attention and have become more than a necessity nowadays. This paper presents an up to date comprehensive overview of energy storage technologies. It incorporates characteristics and functionalities of each storage technology, as well as their advantages and disadvantages compared with other storage technologies. Comparison tables with several characteristics of each storage method are included, while different applications of energy storage technologies are described as well. Finally, several hybrid energy storage applications are analyzed and different combinations of energy storage technologies are reviewed.

Energy storage for electricity generation and related processes: Technologies appraisal and grid scale applications

Energy storage (ES) has become increasingly important in modern power system, whereas no single type of ES element can satisfy all diverse demands simultaneously. This study proposes a hybrid energy storage system (HESS) based on superconducting magnetic energy storage (SMES) and battery because of their complementary characteristics for the grid integration of wind power generations (WPG). This study investigates the mathematical model and the topology of the proposed HESS, which is equipped with a grid-side DC/AC converter, a battery buck/boost converter and a SMES DC chopper. The advanced control strategies comprised of device level and system level are designed. The control strategy for the converters which can be considered as device level is briefly discussed. The significant contribution of this study is proposing a novel system-level control strategy for reasonable and effective power allocation between SMES and battery. According to the control objectives, a fuzzy logic controller optimised with genetic algorithm is adopted. The detailed controller designs are described, meanwhile system stability and HESS operation performance are evaluated. MATLAB simulations are presented to demonstrate the effectiveness of the proposed strategies.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-rpg.2013.0340

Design and advanced control strategies of a hybrid energy storage system for the grid integration of wind power generations

As small-sized superconducting magnetic energy storage (SMES) system is commercially available at present, the function and effect of a small-sized SMES in an EV charging station including photovoltaic (PV) generation system is studied in this paper, which provides a practical application of small-sized SMES. The comparison of three quick response energy storage systems including flywheel, capacitor (super-capacitor) and SMES is also presented to clarify the features of SMES. SMES, PV generation system, and EV battery are connected to a common dc bus with corresponding converters respectively. Voltage source converter (VSC) is used for grid-connection. With characteristic of quick power response, SMES is utilized to maintain the dc bus steady. During the long-term operation of EV charging station, an energy management strategy is designed to control the energy transfer among PV units, SMES, EV battery, and power grid. The EV charging station system is modeled in MATLAB/SIMULINK and simulation tests are carried out to verify the function and performance of SMES.

Application of Small-Sized SMES in an EV Charging Station With DC Bus and PV System

Fast charging is a practical way for electric vehicles (EVs) to extend the driving range under current circumstance. The impact of high-power charging load on power grid should be considered. This study proposes an application of a hybrid energy storage system (HESS) in the fast charging station (FCS). Superconducting magnetic energy storage (SMES) and battery energy storage (BES) are included in HESS. Based on the quick response of SMES and the high energy density of BES, power magnitude and power change rate of FCS can be limited by compensation of HESS. A controller is designed to generate real-time power demand to HESS. As a part of the control strategy, the energy regulation control of SMES is highlighted. The regulation control is necessary for SMES to deal with energy imbalance in continuous operation; meanwhile it is beneficial for battery life. Finally, feasibility of this control strategy is verified by simulation.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-gtd.2015.0110

Application of a hybrid energy storage system in the fast charging station of electric vehicles

A novel flux-coupling type superconducting fault current limiter (SFCL) is proposed in this paper. This type SFCL is composed of two superconducting coupling coils, a controlled switch and two metal oxide arresters (MOAs). The primary coil and the secondary coil, which are wound in the reverse direction and are respectively in parallel with the two MOAs, are connected in parallel through the controlled switch and a main circuit breaker. Under normal condition, due to the non-inductive coupling characteristics between the two superconducting coils, the impedance of the proposed SFCL will be too small to affect the main circuit. After the fault happens, the controlled switch will be opened from its initial closed state, and meanwhile the MOAs will prevent the two coils from being damaged by the overvoltage caused by the switching operation. Since the flux between the coils cannot cancel out each other, the non-inductive coupling will disappear, and then the limiting impedance will be triggered for current-limitation. In order to evaluate the current-limiting performance of the novel flux-coupling type SFCL, a laboratory scale prototype was made. The two superconducting coils were fabricated with Bi2223/Ag, and an anti-parallel IGBT pair was chosen as the controlled switch. According to the test results, it was found that, the fault current could be limited quickly and effectively, and there was no overvoltage during the operation process of the controlled switch.

Current Limiting Characteristics of a Novel Flux-Coupling Type Superconducting Fault Current Limiter

The concerns about the reliability of SMES have always been the obstacle to the practical application of SMES. In this paper, a fuzzy logic-based operating current regulation strategy, aiming at improving the reliability of SMES, has been proposed. In this control strategy, the current of SMES will be maintained in the best range during normal operation. When the temperature of magnet sharply rises after deep power exchange, the current of SMES will be down regulated to reduce ac loss and obtain more thermal stability margin. An application of SMES in microgrid is taken as an example to verify the control strategy. Simulation results based on MATLAB/Simulink demonstrate the feasibility and correctness of the control strategy.

Jing Shi

Papers

Design and advanced control strategies of a hybrid energy storage system for the grid integration of wind power generations

Application of Small-Sized SMES in an EV Charging Station With DC Bus and PV System

Application of a hybrid energy storage system in the fast charging station of electric vehicles

Current Limiting Characteristics of a Novel Flux-Coupling Type Superconducting Fault Current Limiter

Application of SMES in the Microgrid Based on Fuzzy Control