Lessons Learned from the Operating Experience of Battery Energy Storage Systems in the World

With the development of renewable power generation, more battery energy storage systems (BESS) have been installed in power grids, especially for large-scale BESS systems. It is crucial to survey the functions and benefits of these installed storage systems. In this study, numerous large-scale BESS projects, including utility-scale BESSs, were investigated. These battery storage systems were built in America, Asia, Europe and Australia. Each BESS project has its main target and the corresponding operating functions. These functions mainly cover frequency regulation, voltage support, peak shaving, power reliability and resilience enhancement, transmission congestion relief, line upgrade deferral and black start. Additionally, several new trends for BESS developments have been observed. For instance, BESSs are combined with hydrogen power plants to store excess renewable energy; advanced AI software will be applied to real-time trading and control for BESSs by controlling the state-of-charge; the technologies of grid forming for BESSs becomes important; second-life BESSs would be widely utilized in power industry, and dual-battery designs have been proposed to obtain optimal operational strategies. After a complete survey, the results of this study provide important references to the applications of BESSs on power systems.