Sunrun and Tesla Dispatch 580 Megawatts To California’s Grid During Heat Wave, Marking Largest Residential Distributed Power Plant Event In History

Sunrun (RUN) and Tesla (TSLA) report that more than 140,000 home batteries delivered over 580 megawatts of peak power to California’s grid on September 9, 2026, during an extreme heat wave.

Rhea-AI Summary

Sunrun (RUN) and Tesla (TSLA) report that more than 140,000 home batteries delivered over 580 megawatts of peak power to California’s grid on September 9, 2026, during an extreme heat wave.

This is described as the largest residential distributed power plant dispatch to date, with capacity comparable to a large power plant and enough to serve all households in Sacramento County during peak hours. The event, requested by state energy authorities and utilities, ran for three evening hours and aimed to increase operating margin and reduce real-time energy prices. Sunrun and Tesla coordinated 517 megawatts from Powerwalls and 63 megawatts from other batteries, with 110,000 Powerwalls participating and over half owned and operated by Sunrun.

Positive

• 580 MW of peak power dispatched to California’s grid on Sept. 9, 2026
• 140,000+ home batteries coordinated statewide across all three investor-owned utilities
• 517 MW from Tesla Powerwalls and 63 MW from other batteries in the event
• 110,000 Powerwalls participated, with 55% owned and operated by Sunrun
• Follow-on Sept. 10 dispatch delivered an additional 140 MW to the grid
• Combined potential from Sept. 9–10 fleets exceeds 720 MW in a single dispatch
• Brattle Group report estimates up to $206 million in net cost savings to Californians by 2028

Negative

• None.

News Explained

The disclosure adds a separate 140-megawatt dispatch on September 10 and keeps the 720-megawatt figure hypothetical for a same-night combination.

Sunrun and Tesla completed the September 9, 2026 three-hour battery dispatch through California’s DSGS and ELRP grid-service programs, using participating residential batteries as temporarily dispatched grid capacity.

The company says participants benefit from direct compensation for power shared with the grid, making the immediate disclosed consequence operational grid participation rather than a stated change to common ownership.

A separate September 10, 2026 dispatch delivered more than 140 megawatts; the release says more than 720 megawatts could have been delivered if both events had occurred on the same night, so 720 megawatts was not the output of one event.

The release also points to an existing Sunrun, Tesla, and Renew Home initiative targeting more than 16.8 gigawatts of flexible capacity, while a separate Google-funded PG&E resource enrolling nearly 21,000 devices is expected to begin supporting the grid as early as this fall.

Key Figures

Peak power dispatched: More than 580 megawatts Dispatch duration: Three-hour evening period Powerwalls participating: 110,000 Powerwalls +5 more

Peak power dispatched

More than 580 megawatts

September 9, 2026 California grid event

Dispatch duration

Three-hour evening period

September 9, 2026 event

Powerwalls participating

110,000 Powerwalls

September 9, 2026 event

Sunrun-owned Powerwalls

55%

Share of participating Powerwalls

Additional batteries

More than 30,000 batteries

Sunrun customers’ batteries from other manufacturers

Additional dispatch

More than 140 megawatts

September 10, 2026 Southern California Edison event

Potential net cost savings

Up to $206 million

Potential California savings by 2028

Flexible capacity initiative

More than 16.8 gigawatts

Existing Sunrun, Tesla, and Renew Home initiative

Key Terms

distributed power plant, locational marginal price

2 terms

distributed power plant technical

"The combined output marks the largest distributed power plant dispatch event on record"

A distributed power plant is a group of small electricity sources—like rooftop solar, batteries, or small turbines—spread across different locations but coordinated to act like one larger power station. For investors, it matters because this approach can lower transmission costs, increase resilience and flexibility, and create new revenue streams from selling power or grid services; think of many neighborhood generators pooling output like a team instead of a lone player.

locational marginal price technical

"day-ahead locational marginal price exceeding $200 per megawatt-hour"

Locational marginal price (LMP) is the wholesale price of electricity at a specific location on the grid and at a particular moment, reflecting the cost to supply the next increment of power there given local demand, generation, and transmission constraints. It matters to investors because LMPs determine the revenue and operating decisions of generators, the cost of electricity for large consumers and utilities, and signals where grid congestion or investment in new capacity is most valuable—think of it as the local retail price that changes by neighborhood and time because of traffic on the power lines.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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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.

Media Contact
Wyatt Semanek
Sr. Director, Corporate Communications
press@sunrun.com

Investor & Analyst Contact
Patrick Jobin
SVP, Deputy CFO & Investor Relations Officer
investors@sunrun.com

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What triggered the September 9, 2026 distributed power plant dispatch event in California?

The dispatch was coordinated through the California Energy Commission’s Demand Side Grid Support (DSGS)Emergency Load Reduction Program (ELRP). The DSGS event was triggered when the California Independent System Operator’s day-ahead locational marginal price exceeded $200 per megawatt-hour, while the ELRP event was called to coincide with the heat wave by Pacific Gas and Electric Company for batteries in its territory.

How were Sunrun and Tesla customers’ batteries involved across California utilities?

The participating batteries were located statewide, with customers in all three investor-owned utilities’ service territories. Sunrun and Tesla coordinated 517 megawatts from Tesla Powerwalls and 63 megawatts from other batteries, including more than 30,000 Sunrun customer batteries from other manufacturers.

What happened during the separate September 10, 2026 dispatch event?

On September 10, 2026, 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 from their fleets located in that utility’s territory.

How might similar distributed power programs impact costs for Californians?

A report by The Brattle Group, commissioned by Sunrun and Tesla, found that programs like these could provide up to $206 million in net cost savings to Californians by 2028. The report indicates that these savings would benefit all grid-connected customers, and participating customers also receive direct compensation for the power they share with the grid.

What larger initiative are Sunrun, Tesla, and Renew Home pursuing using home batteries and other devices?

The dispatch event supports Sunrun, Tesla, and Renew Home in their existing initiative to unlock more than 16.8 gigawatts of flexible capacity from home batteries, solar, smart thermostats, and electric vehicles for hyperscalers and utilities.

What is the new Google-funded distributed power plant project with PG&E mentioned in the announcement?

Sunrun, Tesla, and Renew Home announced that they will enroll nearly 21,000 existing flexible energy devices into a new, Google-funded distributed power plant with Pacific Gas and Electric Company. The resource is expected to begin supporting the grid as early as the fall following the announcement.