LS Energy Solutions In Commercial Operations For CAISO At Big Rock 200 MW/400 Mwh Energy Storage Site

(MENAFN- GlobeNewsWire - Nasdaq) The Southern California site, developed in partnership with Gore Street Energy Storage Fund (LSE: GSF), is LS-ES's largest energy storage installation to date and the first for the California ISO

CHARLOTTE, N.C., Sept. 04, 2025 (GLOBE NEWSWIRE) -- LS Energy Solutions (“LS-ES”), a leading provider of grid-connected energy storage solutions, announced today that commercial operations have commenced at the Big Rock energy storage site in Imperial County, California. The 200 MW/400 MWh project, developed and operated in partnership with Gore Street Energy Storage Fund (“GSF”), is now providing resource adequacy (RA) and ancillary services for the California Independent System Operator (CAISO) electrical grid.

“We are thrilled to see the Big Rock site in full commercial operation and providing storage services for CAISO,” said Curt Feldman, Vice President at LS Energy Solutions.“As California's grid faces challenges from data center growth, wildfires, and the need to meet carbon reduction goals, utility-scale storage like Big Rock is more critical than ever. Gore Street Energy Storage Fund has been an excellent partner for this project, and we look forward to working with them on future CAISO projects.”

The Big Rock site includes 137 LS-ES AiON-ESS containers storing energy for two-hour durations. LS-ES and GSF currently operate the site at 100 MW of deliverability to supply 400 MWh to CAISO and meet the four-hour discharge stipulation of a 12-year RA contract. In addition to supplying AiON-ESS containers, LS-ES is also supporting the site with operational services that include preventative and capacity maintenance, an extended warranty, and system remote monitoring for the life of the project.

GSF acquired the Big Rock site in February 2023 from clean energy developer Avantus, and it marks the developer's first project for CAISO. Big Rock joins other energy storage investments by GSF in Texas, Ireland, Great Britain, and Germany, with a total operational portfolio of 753.4 MW/924.1 MWh of energy storage assets.

“We are pleased to see Big Rock delivering the full suite of storage services to CAISO, including operation under the 12-year Resource Adequacy contract we have secured," said Alicja Kowalewska-Montfor, Technical Principal at Gore Street Capital.“This marks our first project in CAISO, one of North America's leading grid operators. Our 200 MW/400 MWh site, supported by LS Energy Solutions, will play a vital role in supporting CAISO in building a more flexible grid for Californians, and we look forward to supporting the operator for years to come.”

To learn more about the Big Rock site and LS-ES's energy storage services, visit or meet with the LS-ES team at the RE+ trade show (September 9-11, LS Electric booth F17613 ).

About LS Energy Solutions
LS Energy Solutions, an LS Group company, is a leading provider of grid-connected energy storage solutions. The company brings over a decade of experience innovating energy storage and related technologies, from the first grid-connected lithium-ion storage system and to now having over 1 GW deployed across 250 projects. The company offers a flexible range of battery and power electronics systems for both front-of and behind-the-meter applications, supported by an advanced global manufacturing and testing infrastructure. LS Energy Solutions is a convenient and competitive one-stop supplier for energy storage, from advanced inverters and associated components to fully integrated all-in-one systems. For more information visit .

About Gore Street Energy Storage Fund
Gore Street Energy Storage Fund plc (“GSF” or“the Company”) is London's first internationally diversified listed energy storage fund, launched in May 2018. It holds a portfolio totaling 1.25 GW spread across battery storage facilities in Great Britain and Ireland, Western Mainland Europe and the US. It is listed on the Premium Segment of the London Stock Exchange and included in the FTSE All-Share Index. For more information visit

Media Contact
Justin Williams
Trevi Communications for LS Energy Solutions
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+1 (978) 539-7157‬‬

A photo accompanying this announcement is available at

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