Sunrun and Tesla Dispatch 580 Megawatts of Home Batteries to California’s Grid in the Largest Event of Its Kind

Sunrun Inc. (NASDAQ: RUN), the largest provider of home battery storage and solar in the United States, announced on September 21, 2026 that its fleet and Tesla’s together dispatched more than 580 megawatts of peak power to California’s grid on the evening of September 9. More than 140,000 home batteries took part. Consequently, a collection of equipment sitting in garages and on the sides of houses behaved, for a few hours, like a conventional power plant.

What Actually Discharged

The 580 megawatts break down into 517 megawatts from Tesla Powerwalls and 63 megawatts from other batteries. Roughly 110,000 Powerwalls participated, and Sunrun owns and operates 55% of those. Sunrun also dispatched more than 30,000 of its customers’ batteries from other manufacturers. The companies compare the combined output to the electricity used by every household in Sacramento County during peak hours.

A second, smaller event followed the next evening. Southern California Edison requested a three-hour dispatch during peak hours on September 10, and the two fleets delivered more than 140 megawatts. Sunrun notes that had both events landed on the same night, the combined fleets could have supplied over 720 megawatts. That number is a statement of available capacity rather than a figure either company actually delivered, and it is worth reading as such.

Two State Programs Made the Call

Neither company decided on its own when to discharge. The event ran through two state programs. The first is the California Energy Commission’s Demand Side Grid Support program, which pays customers to reduce load or supply power when the grid is stressed. Sunrun says the September 9 dispatch under that program was triggered when the California Independent System Operator’s day-ahead locational marginal price passed $200 per megawatt-hour. The second is the California Public Utilities Commission’s Emergency Load Reduction Program, a pilot that compensates customers and aggregators for cutting consumption or adding supply during grid emergencies. Sunrun says Pacific Gas and Electric called that event for batteries inside its territory.

The distinction matters for anyone modeling this revenue line. Dispatch volume is not a function of how many batteries Sunrun installs; it is a function of how often the state calls, which depends on weather, prices and program budgets that sit outside the company’s control. Sunrun says participants receive direct compensation for the power they share, although the release does not quantify it.

How Big 580 Megawatts Really Is

Some context helps. The Energy Commission reported in August 2026 that California has 21,112 megawatts of battery storage supporting the grid, of which roughly 3,000 megawatts sits in more than 300,000 smaller systems at homes, schools, farms and businesses. A single coordinated discharge of 580 megawatts therefore represents close to a fifth of everything behind the meter in the state, moving at once.

The trajectory is steep as well. In July 2026, Sunrun described its California fleet as offering up to 425 megawatts of peak dispatchable capacity, and its largest event of the prior summer, on July 29, 2025, averaged more than 360 megawatts over two hours from Sunrun batteries alone. Comparisons need care, because peak figures and two-hour averages are not the same measurement. Even so, the direction is unmistakable.

The Business Underneath the Record

Sunrun reported second quarter 2026 revenue of $870.0 million and net income attributable to common stockholders of $115.2 million, with $712.4 million in cash. The company served 1,205,613 customers and 1,034,738 subscribers, attached storage to 74% of new installations, its highest rate ever, and installed 332.0 MWh of storage in the quarter. Networked storage capacity across the fleet reached 4,647 MWh. Its most recent quarterly filing lists non-recourse debt of $14.53 billion, a reminder that this is a capital-intensive business regardless of how well the batteries perform.

Management also trimmed its outlook at that report. Chief Financial Officer Danny Abajian revised full-year Cash Generation guidance to a range of $200 million to $375 million, excluding equipment safe harbor investments, down from $250 million to $450 million, and Aggregate Subscriber Value to $4.6 billion to $4.9 billion from $4.8 billion to $5.2 billion. He attributed the change to reduced affiliate channel volumes, a delayed ramp in direct sales and modestly higher capital costs.

Chief Executive Officer Mary Powell framed the September event in infrastructure terms, saying Sunrun’s distributed batteries are operating at a scale larger than many peaker power plants combined, and that the benefits reach beyond individual households by helping control electricity costs and reducing the need for new poles and wires. Sunrun also positions the dispatch as evidence for a broader effort with Tesla and Renew Home to unlock more than 16.8 gigawatts of flexible capacity for hyperscalers and utilities.

Strategic Investment Summary

• Record Dispatch: Sunrun (NASDAQ: RUN) and Tesla dispatched more than 580 megawatts of peak power from over 140,000 home batteries to California’s grid on September 9, 2026.
• Fleet Composition: The total comprised 517 megawatts from roughly 110,000 Tesla Powerwalls, 55% of which Sunrun owns and operates, plus 63 megawatts from more than 30,000 batteries by other manufacturers.
• Programs, Not Discretion: The event ran through the California Energy Commission’s Demand Side Grid Support program and the California Public Utilities Commission’s Emergency Load Reduction Program, so dispatch frequency depends on state calls rather than company decisions.
• Scale in Context: California holds about 3,000 megawatts of behind-the-meter battery capacity across more than 300,000 smaller systems, making this single event close to a fifth of that total.
• Second Quarter Results: Sunrun reported $870.0 million of revenue and $115.2 million of net income attributable to common stockholders, with a record 74% storage attachment rate and 4,647 MWh of networked storage.
• Guidance Trimmed: Full-year Cash Generation guidance moved to $200 million to $375 million from $250 million to $450 million, and Aggregate Subscriber Value to $4.6 billion to $4.9 billion from $4.8 billion to $5.2 billion.

Find out more about the latest corporate developments and financial reports at the Sunrun investor relations site.