Published: 7 Jan 2021, 08:49 By: Andy Colthorpe Upton solar farm in Texas, where Vistra deployed its first battery storage system, completed in 2018. Image: Vistra Energy. The world’s largest battery energy storage system (BESS) so far has gone into operation in Monterey County, California, US retail electricity and power generation company Vistra said yesterday. Phase 1 of Moss Landing Energy Storage Facility was connected to the power grid and began operating on 11 December 2020, at the site of Moss Landing Power Plant, a natural gas power station owned by Vistra since it acquired the facility’s previous owner, Dynegy in 2018. At 300MW / 1,200MWh, the BESS is considerably larger than the 250MW / 250MWh Gateway Energy Storage project brought online earlier this year by LS Power, also in California. Not only that, but Phase 2 of Vistra’s project will add another 100MW / 400MWh and is scheduled for completion by August this year.