Tesla and Sunrun set residential battery dispatch record in California

Sunrun and Tesla have set a new record for the largest distributed residential power plant dispatch ever recorded. On September 9, 2026, more than 140,000 home batteries simultaneously discharged power to the California electricity grid during a severe heat wave.

The dispatch delivered a combined peak of 580 megawatts, a capacity comparable to a large conventional power plant. This output was sufficient to power every household in Sacramento County during peak hours. Tesla Powerwalls contributed 517 megawatts of the total, while Sunrun managed over 30,000 additional batteries from other manufacturers.

The event was triggered by surging electricity demand and rising wholesale energy prices during extreme temperatures. The discharge was coordinated through the California Energy Commission’s Demand Side Grid Support program and the California Public Utilities Commission’s Emergency Load Reduction Program to increase the grid’s operating margin and lower real-time energy prices.