Creating Our Clean Energy Future: PG&E Commissions Its Moss Landing Elkhorn Battery

After final testing, the BESS was fully energized and certified for market participation by the California Independent System Operator (CAISO) on April 7, 2022.

PG&E announced today the commissioning of its 182.5-megawatt (MW) Tesla Megapack battery energy storage system (BESS) – known as the Elkhorn Battery – located at its Moss Landing electric substation in Monterey County.

After final testing, the BESS was fully energized and certified for market participation by the California Independent System Operator (CAISO) on April 7, 2022.

Not only does battery energy storage help integrate renewable energy sources, such as solar, it also enhances the overall reliability of California’s ever-changing energy supply. 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.

“We are ushering in a new era of electric system reliability and delivering a vision into the future for our customers with the commissioning of the Tesla Megapack system in Moss Landing. We are committed to safely delivering reliable and clean energy in a way that achieves the greatest value for our customers, but we can’t go it alone into this clean energy future. Projects like this require innovative partners, such as Tesla, and PG&E will continue to seek out and work with the best and brightest to provide breakthrough clean energy solutions for our customers,” said PG&E Corporation Chief Executive Officer Patti Poppe.

The BESS was approved 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.

The Elkhorn Battery system – named for its physical location on the mouth of the Elkhorn Slough on Monterey Bay – was designed, constructed, and is maintained by both PG&E and Tesla, and is owned and operated by PG&E.

It includes 256 Tesla Megapack battery units on 33 concrete slabs. Each unit houses batteries and power conversion equipment in a single cabinet. Transformers and switchgears were also installed along with the Megapacks to connect energy stored in the batteries with the 115 kilovolt (kv) electric transmission system.

The BESS has the capacity to store and dispatch up to 730 megawatt hours (MWh) of energy to the electrical grid at a maximum rate of 182.5 MW for up to four hours during periods of high demand.

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.

The system represents one of the largest utility-owned, lithium-ion battery energy storage systems in the world.

Elkhorn Battery Part of a Growing Trend

PG&E now has contracts for battery energy storage systems totaling more than 3,330 MW of capacity being deployed throughout California through 2024.

To date, 955.5 MW (of the 3,330 MW under contract) of new 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-plus MW of storage capacity (of the 3,330 MW under contract) to come online in 2022 and 2023.