Anthony M. Gee

Bio: Anthony M. Gee is an academic researcher from University of Bath. The author has contributed to research in topics: Energy storage & Battery (electricity). The author has an hindex of 6, co-authored 7 publications receiving 446 citations.

Analysis of Battery Lifetime Extension in a Small-Scale Wind-Energy System Using Supercapacitors

Abstract: Due to the variable characteristics of renewable generation, batteries used in renewable-power systems can undergo many irregular, partial charge/discharge cycles. In turn, this can also have a detrimental effect on battery lifetime and can increase project costs. This study presents a method of improving battery lifetime in a small-scale remote-area wind-power system by the use of a battery/supercapacitor hybrid energy storage system. The supervisory control algorithm and hardware implementation are described and projected long-term benefits of the proposed system are assessed by simulation. A representative dynamic model of the overall system, incorporating realistic wind-speed and load-power variations has been developed. An analysis is presented of the potential improvement in battery lifetime that is achievable by diverting short-term charge/discharge cycles to a supercapacitor energy-storage system. This study introduces a method by which supercapacitor energy storage systems and control algorithms can be evaluated and implemented in the application area considered. The composition of a prototype test system is described and experimental results are presented to demonstrate system feasibility.

A Superconducting Magnetic Energy Storage-Emulator/Battery Supported Dynamic Voltage Restorer

Abstract: This study examines the use of superconducting magnetic and battery hybrid energy storage to compensate grid voltage fluctuations. The superconducting magnetic energy storage system (SMES) has been emulated by a high-current inductor to investigate a system employing both SMES and battery energy storage experimentally. The design of the laboratory prototype is described in detail, which consists of a series-connected three phase voltage source inverter used to regulate ac voltage, and two bidirectional dc/dc converters used to control energy storage system charge and discharge. “DC bus level signaling” and “voltage droop control” have been used to automatically control power from the magnetic energy storage system during short-duration, high-power voltage sags, while the battery is used to provide power during longer term, low-power undervoltages. Energy storage system hybridization is shown to be advantageous by reducing battery peak power demand compared with a battery-only system, and by improving long-term voltage support capability compared with an SMES-only system. Consequently, the SMES/battery hybrid dynamic voltage restorer can support both short-term high-power voltage sags and long-term undervoltages with significantly reduced superconducting material cost compared with an SMES-based system.

Analysis of Trackside Flywheel Energy Storage in Light Rail Systems

Abstract: The objective of this paper is to analyze the potential benefits of flywheel energy storage for dc light rail networks, primarily in terms of supply energy reduction, and to present the methods used. The method of analysis is based on train movement and electrical-network load-flow simulation. The results of the analysis indicate potential energy saving of up to 21.6% due to the introduction of the flywheel energy storage. The energy saving effects of receptivity (or energy transfer from one train to another) are also considered. Additional benefits of the flywheel energy storage in terms of voltage drop improvements of 29.8% and a reduction in peak substation power loading of 30.1% are demonstrated in a test case scenario. A novel traction electrical-network load-flow algorithm using modified nodal analysis (MNA) is described in detail. This allows an intuitive representation of network elements such as trains and substations and a direct solution of substation currents.

Novel battery / supercapacitor hybrid energy storage control strategy for battery life extension in isolated wind energy conversion systems

Abstract: In most autonomous off-grid wind energy systems it is necessary to store energy at times when there is an excess and release it at times when there is a deficit Typically, for small off grid applications such as rural electrification, this is achieved using a conventional battery and in many cases a VRLA (valve regulated lead acid) battery Replacement costs factor significantly into the life-cycle costs of battery systems and one of the shortcomings of the conventional battery is its relatively short cycle life This paper proposes a novel control methodology by which a supercapacitor / battery hybridised energy storage system can be implemented to yield a benefit in terms of reduction in quantifiable aging factors that lead to the reduction in battery life cycle

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

Abstract: 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.

Hybrid energy storage system for microgrids applications: A review

Abstract: 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.

Design and Analysis of Novel Control Strategy for Battery and Supercapacitor Storage System

Abstract: In this paper, a simple novel control strategy is designed and analyzed for a hybrid energy storage system (HESS). In the proposed method, batteries are used to balance the slow changing power surges, whereas supercapacitors (SC) are used to balance the fast changing power surges. The main advantage of the proposed control strategy is that, the slow response of battery system including dynamics of battery, controller, and converter operation, is overcome by diverting the power surges to the SC system. The proposed method inherits charge/discharge rate control to improve the life span and reduce the current stresses on battery. The proposed method features less computational burden as it uses simple control strategy. The detailed experimental results presented validate the proposed control strategy for sudden changes in photovoltaic (PV) generation and load demand.

Emergence of hybrid energy storage systems in renewable energy and transport applications – A review

Abstract: The idea of Hybrid Energy Storage System (HESS) lies on the fact that heterogeneous Energy Storage System (ESS) technologies have complementary characteristics in terms of power and energy density, life cycle, response rate, and so on. In other words, high power ESS devices possess fast response rate while in the contrary, high energy ESS devices possess slow response rate. Therefore, it may be beneficial to hybridize ESS technologies in the way that synergize functional advantages of two heterogeneous existing ESS technologies As a consequence, this hybridization provides excellent characteristics not offered by a single ESS unit. This new technology has been proposed and investigated by several researchers in the literature particularly in the fields of renewable energy and electrified transport sector. In this context and according to an extensive literature survey, this paper is to review the concept of the HESS, hybridization principles and proposed topologies, power electronics interface architectures, control and energy management strategies, and application arenas.

Power Smoothing of Large Solar PV Plant Using Hybrid Energy Storage

Abstract: This paper proposes a power smoothing strategy for a 1-MW grid-connected solar photovoltaic (PV) power plant. A hybrid energy storage system (HESS) composed of a vanadium redox battery and a supercapacitor bank is used to smooth the fluctuating output power of the PV plant. The power management of the HESS is purposely designed to reduce the required power rating of the SCB to only one-fifth of the VRB rating and to avoid the operation of the VRB at low power levels, thus increasing its overall efficiency. The PV plant including the HESS has been modeled using MATLAB/Simulink and PLECS software environment. The effectiveness of the proposed power control strategy is confirmed through extensive simulation results.