As California prepares for yet another summer marked by extreme heat, wildfire risks, and rising electricity demand, Sunrun is significantly scaling up its innovative CalReady distributed power plant. The project now links together 75,000 home solar batteries — four times larger than last year’s setup — becoming one of the most substantial distributed battery networks in the United States.

The timing couldn’t be better, as California’s grid increasingly struggles to meet escalating energy demands amid frequent heatwaves and intensifying wildfire conditions. Traditional centralized power plants often struggle during these peak demand periods, highlighting a critical need for more flexible, decentralized power solutions. Sunrun’s expanded CalReady power plant addresses precisely this issue, creating a robust, distributed energy resource capable of supplying critical backup when the grid needs it most.

Meeting Peak Demand With Decentralized Power

CalReady, originally launched to help ease the stress on California’s power grid, experienced impressive growth this year, expanding from about 16,000 households in 2024 to more than 56,000 homes today. With these additional installations, the virtual power plant now has the capability to deliver up to 375 megawatts of instantaneous peak power, which is enough electricity to supply around 280,000 households, nearly matching the number of homes in Ventura County.

Unlike traditional centralized battery or fossil fuel plants, CalReady leverages thousands of individual residential solar batteries. According to Sunrun CEO Mary Powell, this approach is fundamentally changing California’s energy landscape: “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. CalReady’s decentralized nature eliminates any potential single point of failure while offering greater resilience and flexibility for the state’s evolving energy needs.”

A More Resilient Grid Through Distributed Systems

One of CalReady’s biggest advantages is its decentralized structure. Traditional centralized power facilities, whether fossil-fueled or renewable, are vulnerable to single points of failure. A wildfire, severe storm, or infrastructure malfunction can quickly take these plants offline. By contrast, Sunrun’s distributed network, made up of thousands of independently operating batteries, significantly reduces these risks.

CalReady is actively managed and dispatched by Sunrun, providing reliable daily grid support during peak energy usage hours from 4 to 9 p.m. from May through October. The California Energy Commission recognizes CalReady as the largest aggregation participating in its Demand Side Grid Support program, underscoring the importance and scale of this residential-powered resource.

Financial Incentives & Lower Electricity Costs For Californians

Beyond boosting reliability, CalReady offers substantial economic incentives for California homeowners. Participating households earn compensation of up to $150 annually per battery for allowing Sunrun to utilize stored solar energy during periods of high demand. In 2024 alone, CalReady delivered $1.5 million directly into the pockets of Sunrun customers. This year, with its significant expansion, the project expects total homeowner earnings to approach $10 million.

Paul Dickson, President and Chief Revenue Officer at Sunrun, emphasized the benefits: “CalReady is unlocking meaningful opportunities for families to generate passive income from their existing storage and solar systems. 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.”

This financial model stands in sharp contrast to California’s steadily rising electricity rates, which have consistently outpaced inflation and national averages. By providing alternative revenue streams for homeowners, CalReady also indirectly reduces costs for all California electricity users by offsetting expensive peak-time electricity purchases and delaying costly grid upgrades.

Strong Consumer Demand Fuels Expansion

The rapid growth of CalReady reflects broader consumer demand for home energy storage. At the close of 2024, more than 60% of new Sunrun customers nationwide (and nearly 90% in California) chose to pair batteries with their solar systems. The high adoption rates underscore growing homeowner awareness of the practical, financial, and resilience benefits provided by integrated solar-plus-storage solutions.

Participation in CalReady is straightforward: Sunrun manages battery operations, making the experience seamless for homeowners. Importantly, customers who rely on batteries for emergency backup power are assured that at least 20% battery capacity will always remain available, safeguarding their ability to power essential home functions during local outages.

A Model For National Expansion?

Sunrun’s dramatic expansion of CalReady isn’t just significant for California, as it also offers a compelling blueprint for how distributed energy networks could be replicated nationwide. The successful aggregation of thousands of residential batteries demonstrates how similar networks could offer robust, scalable, and economically attractive solutions elsewhere.

As California enters another challenging summer, Sunrun’s CalReady is more than just a technical achievement. It represents a fundamental shift toward a decentralized, homeowner-powered energy future, one which is capable of effectively meeting both today’s demands and tomorrow’s environmental challenges.