The Rise of Energy Storage in Solar Installations

The Shift to Energy Storage: How Sunrun is Revolutionizing the Solar Industry

Seventy percent of the nearly 29,000 new Sunrun customers last quarter added paired batteries with rooftop solar systems, a significant jump from a year earlier, according to the company. This trend highlights Sunrun’s growing focus on energy storage systems that can support virtual power plants.

Key Statistics

70% of new Sunrun customers added paired batteries with rooftop solar systems last quarter.
A 50% jump in battery attachment rate from a year earlier.
Installed 195,000 solar-and-storage systems at customers’ homes, with attachment rates steadily increasing since 2023.

The surge in battery attachments underscores Sunrun’s shift away from solar-only installations and toward energy storage systems that can provide a reliable source of power during peak demand periods. This shift is driven by the growing interest in virtual power plants, which can dispatch tens or hundreds of megawatts of electricity during peak demand periods.

Virtual Power Plants: A Cheaper Alternative

Virtual power plants (VPPs) network tens of thousands of customer-sited devices, such as home batteries, to dispatch electricity during peak demand periods. Experts say VPPs are cheaper and faster to deploy than utility-scale power plants, which can take several years to permit and build.

“We’re focusing heavily [on] deploying battery devices and reaching penetration and concentration in areas that … have attractive home-to-grid virtual power plant type programs set up,” said Paul Dickson, Sunrun president and chief revenue officer.

California’s Role in the Shift to Energy Storage

California remains the largest state market for residential solar, and policy decisions there have an outsized impact on distributed energy providers like Sunrun.
A new net billing tariff incentivized storage attachments for new residential solar customers, leading to a 50% jump in attachment rate from 2023 to 2024.

Sunrun has installed about 3.2 GWh of distributed storage capacity to date, putting it on track to reach 10 GWh by 2029. The company has a strong presence in California, and its focus on energy storage aligns with the state’s growing interest in VPPs.

Growing Opportunities for Sunrun

35% of Sunrun’s batteries are enrolled in VPP programs, with the company anticipating a growing share.
The Trump administration’s hostility to wind and solar energy may spur Democratic-controlled states to sustain or expand support for customer-sited solar and batteries.
Rumors of revised guidance on clean energy developers may open up new opportunities for Sunrun, but the outcome is unlikely.

Sunrun will have a multi-year backlog of projects that it expects to qualify for the solar investment tax credit beyond its end-of-2027 expiration date, according to the company. The company expects to further expand this backlog — possibly as far out as 2030 — once the U.S. Department of Treasury releases revised “safe harbor” guidance for clean energy developers.

Conclusion

The shift to energy storage in solar installations is a significant trend that underscores Sunrun’s commitment to providing reliable and sustainable energy solutions.