What is an energy storage system?

An energy storage system (ESS) for electricity generation uses electricity (or some other energy source, such as solar-thermal energy) to charge an energy storage system or device, which is discharged to supply (generate) electricity when needed at desired levels and quality. ESSs provide a variety of services to support electric power grids.

What is compressed air energy storage (CAES)?

The United States has one operating compressed-air energy storage (CAES) system: the PowerSouth Energy Cooperative facility in Alabama, which has 100 MW power capacity and 100 MWh of energy capacity. The system’s total gross generation was 23,234 MWh in 2021. The facility uses grid power to compress air in a salt cavern.

What is a battery storage system?

Many battery storage systems, and flywheels and super capacitors, provide rapid response to electricity demand fluctuations on sub-hourly timescales—from a few minutes down to fractions of a second—to keep grid voltage and frequency characteristics within a narrow range and provide an expected level of power quality.

What is the power capacity of a battery energy storage system?

As of the end of 2022, the total nameplate power capacity of operational utility-scale battery energy storage systems (BESSs) in the United States was 8,842 MW and the total energy capacity was 11,105 MWh. Most of the BESS power capacity that was operational in 2022 was installed after 2014, and about 4,807 MW was installed in 2022 alone.

How many energy storage projects are planned in 2023?

All other planned energy storage projects reported to EIA in various stages of development are BESS projects and have a combined total nameplate power capacity additions of 22,255 MW planned for installation in 2023 through 2026. About 13,881 MW of that planned capacity is co-located with solar photovoltaic generators.

What is a small scale battery ESS?

Small scale have less than 1 MW of net generation capacity, and many are owned by electricity end users that use solar photovoltaic systems to charge a battery. EIA publishes data only for small-scale battery ESS. ESSs are not primary electricity generation sources.