Construction and commissioning of a 20 MW battery energy storage system (BESS) in California, USA, has been successfully completed, Greensmith Energy has announced.

The facility is among the largest BESS facilities in North America and capable of providing 80 MWh of electricity over a four-hour period. It was installed at a site in Pomona, California, on behalf of AltaGas, a Canada-based energy infrastructure firm.

The Pomona BESS started operating in December 2016, just four months after AltaGas signed a ten-year energy storage resource adequacy purchase agreement with Southern California Edison.

The project represents the industry’s fastest completion record for a BESS facility of this size, AltaGas said.

Southern California Edison was ordered by regulators to procure energy storage capacity in 2016 to overcome a looming energy shortage in certain parts of California caused by a partial shutdown of a natural gas storage facility in Aliso Canyon.