A unit of AES Corp. has started work on a 400 megawatt-hour (MWh) battery-based energy storage system for the Alamitos Energy Center (AEC) as part of a larger modernization and replacement project of the existing power plant in southern California.

Storage used for the project will be supplied by Fluence, an energy storage and technology services provider formed by Siemens and AES. Equipment will include Advancion 5 batteries and control systems.

AES business unit AES Southland was awarded a 20-year power purchase agreement (PPA) by Southern California Edison in 2014 to provide 100 MW of interconnected energy storage. It is part of a $2 billion repowering initiative in Long Beach to replace aging natural gas peaking facilities with combined-cycle gas capacity and battery energy storage.

The repowering project is expected to be complete in late 2020.

According to the California Energy Commission, plans filed in 2013 proposed a natural gas-fired, fast-starting, combined-cycle gas turbine, air-cooled electrical generating facility with a net generating capacity of 1,936 MW.

In 2015, AES submitted a revised plan to include a 640 MW natural gas-fired, combined-cycle power block and a 400 MW simple-cycle, air-cooled electrical generating facility. Power Block 1 would consist of two natural gas-fired combustion turbine generators in a combined-cycle configuration with two unfired heat recovery steam generators, one steam turbine generator, an air cooled condenser, an auxiliary boiler and related ancillary equipment. Power Block 2 would consist of four simple-cycle CTGs with fin-fan coolers and ancillary facilities.

In April 2017 the Energy Commission approved the construction plans and work began later that year.