‘World’s Largest’ Energy Storage Site Approved as Part of California Solar Project

The California Energy Commission (CEC) has approved the Darden Clean Energy Project, which the agency said is the first to be fast-tracked under the group’s Opt-In Certification program. The commission said the installation features 1,150 MW, or 4,600 kWh, of battery energy storage, along with a 1,150-MW solar array with about 3.1-million panels.

Officials as part of their June 11 announcement about the project said the facility once complete will be the largest battery energy storage system in the world. The Opt-In Certification program, authorized under Assembly Bill 205, provides a consolidated state permitting option for eligible clean energy projects. California has a goal of 100% zero-carbon retail electric sales by 2045, as required by Senate Bill 100. As part of the statute, the environmental review for a project must be completed within 270 days from the point the project application is deemed complete, unless significant project changes arise that require more time to review.

“California is moving faster than ever before to build the clean energy we need, now with the world’s largest solar and battery project,” said California Gov. Gavin Newsom. “With a record amount of clean energy capacity added last year, we’re creating jobs and supporting local communities, all while building a cleaner, more reliable power grid.”

The Darden project will be built on 9,500 acres in western Fresno County, a site that officials said no longer is able to support agriculture. IP Darden I, LLC, a subsidiary of Intersect Power, owns the installation. Darden will connect to the Pacific Gas & Electric (PG&E) grid.

“The transition to 100% clean electricity by 2045 requires bold, utility-scale projects like Darden,” said CEC chair David Hochschild. “This project is significant not only for its size but its cutting-edge design and safety measures.”

Certification Requirements

Projects seeking approval through the Opt-In Certification program are required to provide community and economic benefits. The DCEP includes:

• $2 million in community investments over the next decade starting with a $320,000 commitment to Centro La Familia Advocacy Services, a nonprofit supporting crime victims, family wellness, and civic engagement in rural communities.
• More than 2,000 prevailing-wage construction jobs to support the local workforce throughout the construction period, which will last from 1.5 to 3 years.
• An estimated $169 million in economic benefits to the local area over the project’s lifetime, estimated at 35 years.

“Today’s clean energy projects must do more than just deliver megawatts. They should create value in the communities where they’re built,” said CEC Commissioner Noemí Gallardo. “This project exemplifies a community-focused approach that advances the state’s energy goals while creating benefits for local workers and residents.”

The Darden battery energy storage system is designed to store excess energy produced during peak production periods, and discharge it during periods of high power demand, and at times of lower solar power output, such as evening or nighttime hours.

Safety Standards

Newsom in 2024 initiated a state-level effort to innovate and strengthen safety standards for battery energy storage systems through cross-agency collaboration. Key parts of that program include an update to the California Fire Code to include specific fire safety requirements for stationary lithium-ion battery storage systems. It also supports the California Public Utilities Commission’s approval of new safety standards, and enhanced oversight of emergency plans for grid-scale battery energy storage systems.

California leads the U.S. and trails only China globally in battery storage capacity. The state has more than 200 utility-scale systems, and more than 250,000 commercial and residential installations, totaling more than 15,700 MW statewide.

California officials said the state this year has reached a 100% clean energy goal on 91% of days (138 out of 151) through May. California added 7,000 MW of clean energy capacity to the state power grid last, and has added about 25,000 MW of capacity over the past five years.

The Darden project is expected to employ more than 2,000 workers during construction over the next 18 to 36 months.

San Francisco-based Intersect Power specializes in solar-plus-storage installation. The company said it has a current portfolio of 2.2 of operating solar power, and 2.4 kWh of battery energy storage either operating or under construction. The company said it expects to break ground on an additional 4 GW of solar power, and 10 GWh of battery energy storage, this year, representing a $9-billion investment.

—Darrell Proctor is a senior editor for POWER.