More than 140,000 home batteries dispatched power to California’s statewide energy grid during extreme heat on September 9, 2026, equaling the capacity of a large power plant
SAN FRANCISCO, Sept. 21, 2026 (GLOBE NEWSWIRE) — Sunrun (Nasdaq: RUN) and Tesla (Nasdaq: TSLA) announced today that the companies’ fleets of home batteries dispatched more than 580 megawatts of peak power to California’s grid on the evening of September 9, 2026. The combined output marks the largest distributed power plant dispatch event on record—with enough capacity to power all households in Sacramento County during peak hours.
The dispatch event occurred amid scorching temperatures, elevated demand for electricity, and the resulting increase in wholesale energy rates. At the request of the California Energy Commission and utilities, Sunrun and Tesla discharged their customers’ home batteries to the grid for a three-hour evening period to increase the grid’s operating margin and put downward pressure on real-time energy prices.
Sunrun and Tesla coordinated 580 megawatts of residential battery capacity during the event—combining 517 megawatts from Tesla Powerwalls with 63 megawatts from additional batteries. 110,000 Powerwalls participated in the event; more than half of those (55%) are owned and operated by Sunrun. In addition, Sunrun dispatched more than 30,000 of its customers’ batteries from other manufacturers.
“Sunrun’s distributed home batteries are operating at a scale larger than many peaker power plants combined,” said Sunrun CEO Mary Powell. “Families depend on their Sunrun energy systems for outage protection and energy independence. This historic dispatch shows that the benefits of distributed energy go well beyond individual households as we help control the cost of electricity for all Californians and reduce the need for new costly poles and wires.”
The dispatch event was coordinated through two statewide grid service programs: the California Energy Commission’s Demand Side Grid Support (DSGS) program and the California Public Utilities Commission’s Emergency Load Reduction Program (ELRP). The participating batteries were located statewide, with customers participating in all three investor-owned utilities’ service territories.
The DSGS dispatch event was triggered by the California Independent System Operator’s day-ahead locational marginal price exceeding $200 per megawatt-hour. The ELRP dispatch was an event called to coincide with the heat wave by Pacific Gas and Electric Company for batteries located within its territory.
An even larger distributed power plant event in California is possible from Sunrun’s and Tesla’s battery fleets. The Sept. 9 event did not dispatch the companies’ additional batteries participating in the ELRP program in Southern California Edison’s territory.
However, the following evening, Sept. 10, Southern California Edison requested a three-hour dispatch during peak hours. Together, Sunrun and Tesla delivered more than 140 megawatts of battery capacity to the grid. Had the dispatch events from Sept. 9 and 10 occurred on the same night, Sunrun and Tesla would have had the ability to deliver over 720 megawatts in a single dispatch.
A report by The Brattle Group, commissioned by Sunrun and Tesla, found that these kinds of programs could provide up to $206 million in net cost savings to Californians by 2028. These savings would benefit all grid-connected customers, the report said. Additionally, participants benefit from direct compensation for the power they share with the grid.
The historic dispatch event provides a strong proof point for Sunrun, Tesla, and Renew Home’s existing initiative to unlock more than 16.8 gigawatts of flexible capacity for hyperscalers and utilities from home batteries, solar, smart thermostats, and EVs. The three companies announced earlier this month that they will enroll nearly 21,000 existing flexible energy devices into a new, Google-funded distributed power plant with PG&E. The resource is expected to begin supporting the grid as early as this fall.
About Sunrun
Sunrun Inc. (Nasdaq: RUN) is America’s largest provider of home battery storage, solar, and home-to-grid power plants. As the pioneer of home energy systems offered through a no-upfront-cost subscription model, Sunrun empowers customers nationwide with greater energy control, security, and independence. Sunrun supports the grid by providing on-demand dispatchable power that helps prevent blackouts and lowers energy costs. Learn more at www.sunrun.com.
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