Sunrun’s Distributed Power Plant Quadruples in Size to 75,000 Solar-Powered Batteries to Support California’s Grid

Rhea-AI Summary

Sunrun (RUN) has significantly expanded its CalReady virtual power plant to include over 56,000 customer solar-plus-battery systems, totaling approximately 75,000 batteries. The system is expected to deliver an average of 250 megawatts per two-hour event, with potential peaks of 375 megawatts—enough to power 280,000 homes. This marks a quadruple increase from 2024, when 16,000 households delivered 48 megawatts on average. The program operates daily from 4-9 PM between May and October, compensating customers up to $150 per battery. In 2024, CalReady generated over $1.5 million in customer value, with 2025 projections reaching nearly $10 million. Notably, Sunrun's storage attachment rate reached 60% company-wide and nearly 90% in California by end-2024. The system maintains a minimum 20% backup reserve for participating customers during outages.

Positive

• Quadrupled power plant capacity to 75,000 batteries, reaching up to 375 megawatts peak power
• Expected to generate nearly $10 million in customer compensation in 2025, up from $1.5 million in 2024
• High customer adoption with 90% storage attachment rate in California
• Generates additional revenue stream for Sunrun through battery dispatching payments
• No additional land or infrastructure costs due to decentralized nature

Negative

• Limited battery reserve of 20% during grid support events
• Operational window restricted to 4-9 PM from May through October

Insights

Energy Markets Analyst

Sunrun's VPP expansion creates new revenue streams, strengthens market position, and demonstrates viability of distributed energy resources at utility scale.

The quadrupling of Sunrun's CalReady virtual power plant to 75,000 batteries from 56,000 customers represents a significant milestone in distributed energy resources. The program's scale—delivering an average of 250 megawatts with peaks of 375 megawatts—demonstrates that aggregated residential systems can now rival utility-scale projects while offering enhanced resilience through geographic distribution.

The financial structure creates multiple value streams: customers receive up to $150 per battery (approximately $10 million collectively this year, up from $1.5 million last year), while Sunrun generates revenue for dispatching services. This transforms Sunrun's business model beyond equipment installation to include recurring grid service revenue.

California's storage attachment rate of nearly 90% indicates Sunrun's "storage-first" strategy is gaining significant traction. By focusing on the critical 4-9pm window from May through October, Sunrun targets precisely when the grid is most stressed and wholesale prices typically peak.

The program's expansion from 16,000 households last year to 56,000 today demonstrates Sunrun's ability to rapidly scale their virtual power plant platform. This positions the company not just as a solar installer but as a sophisticated energy service provider capable of orchestrating distributed resources as a unified grid asset, creating a competitive advantage in the evolving energy landscape.

Grid Systems Specialist

Sunrun's 375MW virtual power plant demonstrates grid-scale viability of distributed resources, providing targeted relief during critical demand periods.

At 375 megawatts peak capacity from 75,000 distributed batteries, Sunrun's expanded CalReady program represents a fundamental shift in power system architecture. This virtual power plant rivals mid-sized conventional generation facilities but with greater resilience through geographic distribution across 56,000 homes.

The targeting of the 4-9pm window directly addresses California's most vulnerable grid period when solar generation declines while demand remains high—the classic "duck curve" challenge. By storing midday solar production for evening dispatch, these systems provide a direct solution to intermittency issues without requiring new transmission infrastructure or land use.

The scale achieved—enough power for approximately 280,000 homes—demonstrates that virtual power plants have crossed the threshold from experimental projects to commercially viable grid assets. This transition has profound implications for grid planning, potentially offsetting traditional infrastructure investments.

The distributed nature eliminates any single point of failure, a critical advantage over conventional power plants. Each participating home maintains a 20% battery reserve for backup power during outages, balancing grid support with customer resilience. This represents the emerging reality of a two-way grid where households function as both consumers and producers of energy services, fundamentally changing how we conceptualize and operate electrical systems.

Sunrun customers create one of the nation’s largest solar-powered battery resources to bolster grid reliability and help prevent blackouts by networking together tens of thousands of distributed home storage systems

SAN FRANCISCO, May 01, 2025 (GLOBE NEWSWIRE) -- Sunrun (Nasdaq: RUN), the nation's leading provider of clean energy as a subscription service, announced today that its CalReady power plant has more than quadrupled in size as the summer heat begins to stress the state’s energy grid. More than 56,000 Sunrun customers’ solar-plus-battery systems—totaling approximately 75,000 batteries—will provide critical energy to California's grid during times of high energy prices, heat waves, and other grid emergency events while simultaneously lowering energy costs for all ratepayers.

“Sunrun is leading the transformation of the energy grid with a customer-led revolution to a more reliable, energy independent way to power their homes while at the same time being a solution to help other Californians who rely solely on the grid,” said Sunrun CEO Mary Powell. “The expansion of CalReady highlights our increasing role as a critical energy provider and underscores the system-wide value we’re delivering to ratepayers, utilities, and the grid.”

Sunrun’s CalReady power plant is the largest home storage aggregation in the California Energy Commission's Demand Side Grid Support program. CalReady is available to support the state’s grid each day from 4 to 9 p.m. from May through October. This is the second year that Sunrun has operated CalReady as the nation’s largest virtual power plant.

In 2024, Sunrun’s CalReady power plant enrolled over 16,000 households and delivered an average of 48 megawatts of stored solar energy to the grid during summer heat waves, reaching an instantaneous peak of 54 megawatts. This year, CalReady’s power output has more than quadrupled and is expected to deliver an average of 250 megawatts per two-hour event, with the ability to reach an instantaneous peak of up to 375 megawatts—enough to power approximately 280,000 homes, equivalent to all of Ventura County, California.

“Sunrun has created one of the largest batteries in the country, rivaling large-scale utility projects but without taking up additional land or requiring costly new infrastructure,” Powell added. “CalReady’s decentralized nature eliminates any potential single point of failure while offering greater resilience and flexibility for the state’s evolving energy needs.”

Sunrun customers enrolled in CalReady are compensated up to $150 per battery for sharing their stored solar energy, and Sunrun is paid for dispatching the batteries. Last year, CalReady delivered more than $1.5 million in value to Sunrun customers and helped lower costs for all ratepayers, reduced pollution, and stabilized the grid for all electric customers in the state. This year, Sunrun customers are expected to collectively receive nearly $10 million for participating in the virtual power plant.

“Being rewarded for sharing energy with the grid from our two batteries makes CalReady a no-brainer,” said San Jose resident and Sunrun customer Tom Weldon. “This will be our third year participating in Sunrun’s virtual power plants. We appreciate the relationships Sunrun develops with customers and utilities to create these programs that have mutual benefits. It’s a win all around.”

Sunrun’s direct compensation to customers is a stark contrast to the double-digit utility rate hikes in California, which are growing faster than inflation and significantly faster than the average electricity rates across the country.

“CalReady is unlocking meaningful opportunities for families to generate passive income from their existing storage and solar systems,” said Sunrun President and Chief Revenue Officer Paul Dickson. “Now in its second year, our rapidly growing power plant is proving that grid operators can depend on distributed energy resources to deliver reliable, cost-effective services at scale when critical emergency power is most needed.”

The scale of CalReady is a direct result of Sunrun’s storage-first strategy. At the end of 2024, more than 60% of new Sunrun customers chose to add battery storage to their solar system. In California, the storage attachment rate was even higher at nearly 90%.

Sunrun actively monitors and dispatches participating batteries, making it a hassle-free experience for customers enrolled in CalReady. For customers with outage protection, batteries will still retain, at minimum, a backup reserve of 20% so that they can continue to power their homes in the event of a local power outage.

About Sunrun
Sunrun Inc. (Nasdaq: RUN) revolutionized the solar industry in 2007 by removing financial barriers and democratizing access to locally-generated, renewable energy. Today, Sunrun is the nation’s leading provider of clean energy as a subscription service, offering residential solar and storage with no upfront costs. Sunrun’s innovative products and solutions can connect homes to the cleanest energy on earth, providing them with energy security, predictability, and peace of mind. Sunrun also manages energy services that benefit communities, utilities, and the electric grid while enhancing customer value. Discover more at www.sunrun.com

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

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

FAQ

How many batteries are in Sunrun's (RUN) CalReady virtual power plant in 2025?

Sunrun's CalReady virtual power plant includes approximately 75,000 batteries across over 56,000 customer solar-plus-battery systems.

How much power can Sunrun's (RUN) CalReady virtual power plant generate in 2025?

The CalReady power plant can deliver an average of 250 megawatts per two-hour event, with the ability to reach peak output of 375 megawatts, enough to power about 280,000 homes.

How much compensation do Sunrun (RUN) customers receive for participating in CalReady?

Customers enrolled in CalReady receive up to $150 per battery for sharing their stored solar energy, with total customer compensation expected to reach nearly $10 million in 2025.

What is Sunrun's (RUN) battery attachment rate in California?

By the end of 2024, nearly 90% of new Sunrun customers in California chose to add battery storage to their solar system.

When does Sunrun's (RUN) CalReady virtual power plant operate?

CalReady operates daily from 4 PM to 9 PM between May and October to support California's grid during peak demand periods.