MOSS LANDING — PG&E’s battery energy storage system saw an operational failure during testing, prompting a delay in its return to service until June 30, 2026.
PG&E’s Elkhorn battery storage system, comprising 256 Tesla megapack batteries, automatically disconnected from the electrical grid when the nearby Vistra battery storage system ignited in January. The Elkhorn system remained inactive until June, when Tesla, which maintains the system, began a series of operational and safety checks in hopes of resuming operations that month. During its tests, a clamp failure in one of the megapacks caused a coolant leak. The issue did not result in any injuries, power outages or fires, PG&E said in a statement.
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Tesla is now making plans for inspections and repairs, pushing the system’s estimated return-to-service date back a year. In the meantime, the system will remain largely disconnected from the grid, connecting occasionally to maintain a “minimum state of charge” and avoid damaging the batteries, said Paul Doherty, a PG&E representative.
Battery energy storage facilities are designed to store energy that can then be used later. They’re often used to integrate renewable energy resources into the electricity grid — allowing the use of solar energy at night, for example. The Elkhorn system makes up a relatively small percentage of PG&E’s contracted battery storage capacity, so its inactivity hasn’t had effects on the electricity grid or on consumers, according to Doherty. Battery storage is an important part of California’s energy mix, though, and resuming the system’s operations will ensure the grid is reliable and mitigate issues such as rolling blackouts, he added.
Despite the utility of battery storage facilities, January’s fire, which burned for days, spurred a wave of opposition to these systems. In the months following the blaze, the Santa Cruz County Commission on the Environment hosted a series of public workshops at which experts presented information on battery storage. Several attendees showed up protesting the proposed construction of a new battery storage facility at 90 Minto Road in unincorporated Watsonville, voicing concerns that the technology was unsafe for the environment and for human health.
In order for the community to feel safe with the Elkhorn system going back online next year, PG&E must ensure that they can identify operational issues before they cause problems, said Glenn Church, a Monterey County supervisor who represents Moss Landing. “There needs to be full transparency on what the problems are and how it is being addressed,” he wrote in an email.
PG&E has taken a “conservative approach” to restarting the system, said Doherty. “Our top priority is ensuring the safety of our communities and the safe operation of our facilities,” he said. He added that PG&E has had emergency action plans since before the Elkhorn system came online in 2022, and has several other safety precautions in place such as a FEMA-certified incident management team and a continuous air monitoring system.
PG&E is coordinating with the county to further develop emergency plans, and will incorporate any new “industry learnings and best practices” that come from Vistra’s investigation of the root cause of the fire, Doherty said.
Church noted that the Elkhorn system coming back online will only affect residents if there’s an accident, further stressing the need for proper safety precautions. PG&E’s delay in returning the Elkhorn system to service, and the emphasis on safety, is “a positive step,” Church wrote in an email.