California solar-plus-storage project with world’s largest BESS fully online

LinkedIn
Twitter
Reddit
Facebook
Email

The Edwards & Sanborn solar-plus-storage project in California is now fully online, with 875MWdc of solar PV and 3,287MWh of battery energy storage system (BESS) capacity, the world’s largest.

The 4,600-acre project in Kern County is made up of 1.9 million PV modules from First Solar and BESS units from LG Chem, Samsung and BYD totaling 3,287MWh of energy storage capacity.

That makes it bigger than the current largest BESS in the world, Vistra’s 750MW/3,000MWh facility at Moss Landing, also in California, which also came online in two phases.

It has now reached ‘substantial completion’ and is ‘fully online’, Mortenson said this week. Energy-Storage.news has asked Mortenson and project owner Terra-Gen what ‘substantial completion’ means and will update this article if and when a response is received.

This article requires Premium SubscriptionBasic (FREE) Subscription

Try Premium for just $1

  • Full premium access for the first month at only $1
  • Converts to an annual rate after 30 days unless cancelled
  • Cancel anytime during the trial period

Premium Benefits

  • Expert industry analysis and interviews
  • Digital access to PV Tech Power journal
  • Exclusive event discounts

Or get the full Premium subscription right away

Or continue reading this article for free

Engineering, procurement and construction (EPC) contractor Mortenson started construction around three years ago and the first phase, comprising about half of the total capacity, came online in late 2021.

The project has an interconnection capacity of 1,300MW. Its offtakers include the city of San Jose, utilities Southern California Edison (SCE) and Pacific Gas & Electric (PG&E), community choice aggregator (CCA) Clean Power Alliance, and coffee chain shop Starbucks.

Although the MW power of the BESS has not been revealed, most BESS projects in California are 4-hour duration (to qualify for grid operator CAISO’s Resource Adequacy framework) which would make this BESS 821MW.

Part of the project is located on the Edwards Air Force Base and Mortenson said the project was the largest public-private collaboration in US Department of Defense history.

“Now fully operational, this facility is a transformational project in the industry and is providing resiliency to the grid,” said Brian Gorda, VP of engineering at Terra-Gen. 

Terra-Gen’s other notable energy storage project is the 140MW/560MWh Valley Center BESS, also in California, though that project was in the headlines in 2023 for the wrong reasons (including a battery fire and a theft of decommissioned batteries).

Energy-Storage.news’ publisher Solar Media will host the 5th Energy Storage Summit USA, 19-20 March 2024 in Austin, Texas. Featuring a packed programme of panels, presentations and fireside chats from industry leaders focusing on accelerating the market for energy storage across the country. For more information, go to the website.

3 November 2026
Málaga, Spain
Understanding technology and supplier selection for Europe’s utility-scale PV market in 2027. PV ModuleTech Europe 2026 is a two-day conference that tackles these challenges directly, with an agenda that addresses all aspects of PV module, inverter and battery supplier selection; product availability, technology offerings, supply chain traceability, quality assurance, factory auditing, system reliability, and supplier bankability.

Read Next

Premium
October 8, 2026
Energy-Storage.news Premium speaks with Freeman Hall, CEO of second-life BESS firm B2U Storage Solutions.
October 8, 2026
Annual battery energy storage system (BESS) failures per-deployed-GWh declined 98% globally between 2018 and 2025, as installed BESS capacity grew exponentially.
October 7, 2026
The first half of the year saw mixed results among China’s leading ESS suppliers, though generally the industry is still performing strongly, writes PV Tech ESS analyst Charlotte Gisbourne. 
October 7, 2026
US energy holding company and project developer-owner NextEra Energy has suspended operations at two energy storage facilities in Long Island, New York, US.
October 7, 2026
Having just begun construction on a 2.8GWh BESS in Belgium, Giga Storage has progressed its 1.4GWh project in Germany to the ready-to-build stage.