A battery energy storage system (BESS) is a technology that stores electrical energy in batteries for later use.
It is designed to store excess electricity typically generated by renewable energy sources, such as solar or wind, and to release that electricity when high demand or intermittent generation sources are not available. Batteries used in energy storage systems can be of many types, including lithium-ion, lead-acid, liquid flow batteries, or other emerging technologies. The choice of battery technology depends on specific requirements such as cost-effectiveness, energy capacity, response time and cycle life.