EDP Renewables North America (EDPR NA) has completed Sandrini Energy Storage, a 92-MW/368-MWh battery energy storage system (BESS) in Kern County, California.

The new facility is co-located with the 300-MW Sandrini Solar energy site. The Redwood Coast Energy Authority (RCEA) holds an energy storage service agreement for 100% of the project's battery capacity, along with 100 MW of the solar site's generating capacity.

Battery storage systems charge when electricity is plentiful — in California, typically at midday when solar output peaks — and discharge it later, when demand rises and solar generation tapers. Grid operators describe this daily pattern of midday solar surplus followed by an evening demand peak as the "duck curve," and smoothing that swing has become the core job of the state's growing fleet of utility-scale batteries. At Sandrini, the 368 MWh of storage paired with 92 MW of power capacity equates to four hours of discharge at full output. Co-locating batteries with a solar plant — a configuration U.S. developers increasingly favor for new utility-scale projects — allows the combined site to deliver clean electricity beyond daylight hours.

RCEA is a joint powers authority serving Humboldt County on California's North Coast that operates a community choice energy program, under which local governments procure power for their communities while the incumbent utility continues to deliver it. Its Sandrini contracts illustrate how such offtakers can secure clean energy capacity from projects built hundreds of miles from their service area. Kern County, where Sandrini is located, sits in the state's southern Central Valley and ranks among California's leading regions for wind and solar development. California law — SB 100, enacted in 2018 — calls for 100% clean electricity by 2045, and the state has rapidly expanded grid-scale storage in recent years to shift solar output into evening hours; it now hosts the largest fleet of utility-scale batteries of any U.S. state.

EDPR NA is the North American arm of EDP Renewables, the global renewable energy developer whose parent company is Portuguese utility EDP.

"Sandrini Energy Storage represents an important investment in California's energy future," said Sandhya Ganapathy, CEO of EDPR NA. "Energy storage transforms renewable power into reliable, around-the-clock electricity, ensuring clean energy is available when demand is highest. Projects like Sandrini strengthen grid resilience, support economic growth and help build a more affordable, dependable energy framework for California. We're grateful to work hand in hand with our communities and Redwood Coast Energy Authority to bring Sandrini online."

The project is expected to generate $5 million in local revenue, which will support infrastructure such as schools, roads and emergency services. Construction of the facility sustained about 50 jobs.

Across California, EDPR NA operates 1.23 GW of renewable energy capacity spanning wind, solar and energy storage, capable of powering more than 485,000 California homes.

"The addition of the Sandrini Energy Storage project to our portfolio supports RCEA's goals of building new, clean capacity that matches our customers' energy needs and enhances the generation delivered by Sandrini Solar, while also supporting grid reliability," said RCEA Executive Director Beth Burks.

News item from EDP Renewables North America, published by Solar Power World.