On September 9, during a heat wave, Tesla and Sunrun dispatched 580 MW of power from a network of over 140,000 residential batteries to the California grid. This three-hour event represents the largest recorded instance of a residential distributed power plant operation.
The fleet included approximately 110,000 Tesla Powerwalls, which provided 517 MW, and over 30,000 batteries from other manufacturers, contributing 63 MW. Sunrun manages 55% of the total battery fleet involved in this initiative.
The energy was delivered through the California Energy Commission’s Demand Side Grid Support program and the California Public Utilities Commission’s Emergency Load Reduction Program. The following day, September 10, Sunrun dispatched an additional 140 MW at the request of Southern California Edison.
A report by the Brattle Group estimates that such dispatch models could generate up to $206 million in net savings for California by 2028. Homeowners participating in these programs receive payments for the electricity supplied to the grid during peak demand periods.
