UK Investment Fund acquires 400-MWh Battery Storage site being developed in California

Energy firm Avantus has sold its Big Rock 1 energy storage project in California to Gore Street Energy Storage Fund, a U.K.-based publicly traded fund managed by Gore Street Capital.

Avantus claims the 200-MW, two-hour (400 MWh) energy storage system is set to be one of the largest energy storage projects in Imperial County, California.

By capturing clean energy produced throughout the day and discharging it during periods of high demand at night, Big Rock 1 will enhance grid resiliency and complement the region’s existing renewable energy resources, the company says. It will transmit into the California Independent System Operator (CAISO) grid.

Additionally, the project is expected to create 90 construction jobs and provide significant tax revenue and other benefits to Imperial County communities.

Construction of Big Rock 1 is anticipated to begin in the second half of this year, with completion slated for late 2024. The energy storage facility is expected to provide firm, reliable power, and offer resource adequacy and ancillary services to the CAISO market.

Under the deal, Avantus will continue to oversee the project’s development and construction, with Gore Street Capital contributing its global operating and technical experience. Following recent acquisitions in Texas, Big Rock 1 is Gore Street’s first acquisition in California and its largest acquisition to date in the U.S.

The Big Rock 1 energy storage project is part of Avantus’ ongoing partnership with Imperial Country, which began a decade ago with the development of the 800 MW Mount Signal solar cluster.

Avantus (formerly 8minute) has more than 90 projects currently in development across California, Texas and the southwestern U.S. Its clean energy pipeline exceeds 50 GW of system capacity, including 42 GW of solar and 78 GWh of energy storage, enough to provide power for more than 30 million people.

Earlier this month, Avantus announced that construction had begun on its 147-MWdc Galloway 2 solar project in Texas. Galloway 2 is majority-owned by Allianz Capital Partners. 

In 2022, the state of California is estimated to have added close to 2.5 GW of battery storage capacity, most of that paired with solar energy in the nation's No. 1 state for solar PV power, according to S&P Global Market Intelligence.