Battery energy storage system (BESS)

A battery energy storage system (BESS) is a stationary installation that stores electrical energy in batteries for later discharge, used for grid balancing, peak shaving, and integrating renewable generation. Under Regulation (EU) 2023/1542 the batteries within a stationary BESS generally fall under the industrial battery category, so units with a capacity greater than 2 kWh require a battery passport from 18 February 2027. Stationary storage is also a leading destination for second-life batteries, where former EV modules are reused after their automotive duty.