Applications of energy storage systems in power grids with and without renewable energy integration-A comprehensive review

Energy storage system (ESS) is recognized as a fundamental technology for the power system to store electrical energy in several states and convert back the stored energy into electricity when required. Some excellent characteristics such as availability, versatility, flexible performance, fleet response time, modularity etc., make ESS more attractive for power system applications. The ESS has signification contributions and applications to operate the power system optimally in power grids with and without integrating renewable energy (RE) systems. This paper presents a comprehensive review of ESS technologies and their applications in power grids. Five different types of ESS, namely mechanical, chemical, electrical, electro-chemical and thermal, are elaborately explored with their key characteristics and applications. A summary of comparative analysis to find the appropriate ESS for power system applications and an analysis of the practical implementation of different ESS worldwide have been presented briefly, reflecting the suitability of ESS for power system applications. The comparative analysis further demonstrates the nature of various ESS, including their advantages and limitations in specific applications. The major challenges from these analyses are identified to be the capacity of ESS, RE integration, high maintenance and implementation cost of ESS, ESS degradation, waste management and asso-ciated environmental pollution. Moreover, the review finds out that there are still numerous challenges in terms of technology and economy that need to be addressed to make the practical applications of ESS viable for power industries. The reviews also identify recent key researches that can effectively address those issues and explore the future directions researchers can undertake to improve various characteristics of ESS. Finally, the transition pathway to promote ESS for power systems applications with and without integration of RE systems is discussed to demonstrate the possibility and potentiality of large-scale ESS deployment for a sustainable climate-friendly future.