Californian investor-owned utility San Diego Gas & Electric has ordered a 10MW, six-hour battery energy storage system (BESS), dubbed Emerald, from Mitsubishi Power.

Mitsubishi is supplying its solution for the Pala-Gomez Creek BESS project announced last month when it was authorised by California Public Utilities Commission (CPUC), as reported by Energy-storage.news. The BESS is set to enter commercial operation on 31 January 2023.

The BESS project Mitsubishi Power is delivering to is one of three being developed for SDG&E totalling 161MW/664MWh which were authorised, with the other two being provided by Fluence and ConEdDev.

It is the Tokyo-headquartered company’s eighth BESS project in California bringing the total in the state to 280MW/1,140MWh. The company’s Emerald storage solution includes full turnkey design, engineering, procurement, and construction, as well as a 10-year long-term service agreement.

The project will repower an existing energy storage site, the company said, and will use its energy management system (EMS) the Emerald Integrated Plant Controller. The BESS is a lithium iron phosphate (LFP) battery system.

The Pala-Gomez Creek BESS is to be located at an existing SDG&E battery storage yard adjacent to the Pala substation in San Diego county. It was the result of efforts by the investor-owned utility to identify potential future energy storage sites that can leverage existing infrastructure.

California is the main driver of the energy storage market in the US, accounting for 90% of utility-scale deployments in 2021. Its three investor-owned utilities have in the last few years been directed by the regulator to procure additional, clean energy resources to bolster the grid in light of fossil fuel retirements but also increased wildfire risk. It plans to have a zero-carbon electricity grid by 2045.