Pacific Gas and Electric Company (PG&E) held an official grand commissioning ceremony of its new battery energy storage system (BESS) - the Elkhorn Battery, located at its Moss Landing electric substation in Monterey County, California. 

The Elkhorn Battery consists of a total of 256 Tesla Megapacks (roughly 3 MWh each), installed on 33 concrete slabs. The total energy capacity is 730 MWh, while power output is up to 182.5 MW, available for up to four hours during periods of high demand. With such specs, it's one of the largest BESS in the world.

The entire project took a few years, starting from approvals by the California Public Utilities Commission (CPUC) in November 2018 and by the Monterey County Planning commission in February 2020. Site construction began in July 2020, while on April 7, 202,2 the system was fully energized and certified for market participation by the California Independent System Operator (CAISO).

There are two main purposes of the Elkhorn Battery -to help integrate renewable energy sources and to enhance the overall reliability of the grid.

"Batteries are charged when energy demand is low (or when solar production is high) and then provide additional capacity by sending that reserved power to the grid when demand grows."

" The Elkhorn Battery enhances reliability by addressing capacity deficiencies that have resulted from increased local energy demand. It participates in the CAISO wholesale electric markets, providing energy and ancillary service – such as serving as an operating reserve that can quickly be dispatched to ensure there is sufficient energy to meet demand – to the CAISO-controlled grid."

As we can see in the videos from the commissioning ceremony, a Tesla Cybertruck prototype appeared at the event (more on that in a separate post).


It's worth noting that to date, some 955.5 MW (of the 3,330 MW under contract) of battery storage capacity has been connected to California’s electric grid including:

  • 182.5 MW PG&E Elkhorn Battery in Monterey County, commissioned 2022
  • 200 MW Diablo Storage System in Contra Costa County, commissioned 2022
  • 60 MW Coso Battery Storage located in Inyo County, commissioned 2022
  • 400 MW Vistra Moss Landing Battery Energy Storage Facility in Monterey County, commissioned 2021
  • 63 MW NextEra Blythe system in Riverside County, commissioned 2021
  • 50 MW Gateway system in San Diego County, commissioned 2021

PG&E anticipates an additional 1,400+ MW of storage capacity will come online in 2022 and 2023.

PG&E BESS in Moss Landing, California in brief:

  • 182.5 MW and 730 MWh at PG&E’s electric substation in Moss Landing California
    730 MWh is comparable to 7,300 electric cars with 100 kWh batteries each
  • 256 Tesla Megapacks (roughly 3 MWh each) on 33 concrete slabs
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