Sunrun installed nearly half of all U.S. residential battery storage capacity added in 2025, new SEIA report shows
San Francisco-based Sunrun installed 1.5 gigawatt-hours of residential battery storage in 2025 — nearly half of the 3.1 GWh added nationally that year, according to SEIA’s inaugural U.S. Energy Storage Market Outlook. The company dropped those numbers on March 12, 2026, putting its share at roughly 48% of the sector’s total.
That kind of concentration from a single installer is rare in any energy segment. It raises real questions about how Sunrun got there — and what it’s planning next.
Sunrun claims nearly half of U.S. residential storage market in 2025
The 48% figure isn’t just a flashy headline. It reflects a company that has pulled way ahead of every other residential installer. Per SEIA’s cumulative data, Sunrun has now put in more than 237,000 storage and solar systems, totaling roughly 4.0 GWh of Networked Storage Capacity — 44% of the 9 GWh of residential energy storage installed across the U.S. since the industry began.
residential storage market added 3.1 GWh in 2025 alone, and Sunrun’s 1.5 GWh slice is larger than what the entire market produced in most prior years combined.
So Sunrun hasn’t just dominated one year. It’s captured nearly half of all residential battery storage ever deployed in this country.
The scale is worth sitting with. The U.S. residential storage market added 3.1 GWh in 2025 alone, and Sunrun’s 1.5 GWh slice is larger than what the entire market produced in most prior years combined. One company holding that kind of share in a fast-growing sector doesn’t happen by accident — it requires sustained execution across sales, installation, and grid integration simultaneously.
Company’s strategic shift toward storage drives market dominance
CEO Mary Powell pointed straight at a deliberate internal strategy. “Our deliberate and decisive pivot to provide Americans with energy independence is why Sunrun leads the residential energy storage sector,” she said in the March 12 announcement.
That pivot shows up clearly in the attachment rate — the share of new solar installs that also include a battery. In Q4 2025, Sunrun’s storage attachment rate hit a record high of 71%. Nearly three out of every four new systems it installed came with a battery.
A high attachment rate matters because it compounds growth. Each solar customer who adds storage joins Sunrun’s grid-connected network, what the company calls its distributed power plant. In 2025, that network dispatched nearly 18 GWh of energy back to the grid, with a combined peak output of 425 MW. Sunrun projects more than 10 GWh of dispatchable capacity will be online by end of 2028.
Grid support and backup power delivered to customers in 2025
Those 18 GWh dispatched to grids in 2025 are equivalent to powering 15 million homes for one hour. The dispatches weren’t random — they happened during peak demand periods, when grid stress is highest and outage risk spikes. According to Sunrun, the network helped prevent blackouts while also putting downward pressure on energy costs for ratepayers broadly, not just its own customers.
The backup numbers on the customer side are just as concrete. Sunrun’s storage customers received 3.8 million hours of backup power in 2025, spread across more than 650,000 unique outage events. That’s a real measure of how often the grid failed — and how consistently batteries filled the gap.
California remains Sunrun’s stronghold. The company installed more storage capacity there in 2025 than the next 40 top battery installers combined, according to the California Solar and Storage Association. That dominance in the country’s historically largest storage market has been a key foundation of its national lead.
Texas expansion and new partnerships signal next growth phase
California may not hold that top-market status much longer. SEIA’s report flags Texas as on track to surpass California as the nation’s largest energy storage market in 2026, and Sunrun is already moving there. The company reported more than 50% year-over-year growth in solar-plus-storage installations in Texas in 2025.
Partnerships with NRG, Tesla, and Vistra are central to that push. The model pairs storage-plus-solar systems with optimized electricity rate plans, giving customers a financial reason to add storage while expanding the grid-support network at the same time.
President and Chief Revenue Officer Paul Dickson laid out two distinct value propositions for the Texas market: backup power for customers during severe weather, and grid benefits for retail electricity providers. “There’s growing interest in the quick-deployment nature of Sunrun’s storage assets,” he said, adding that the company expects to launch additional retail electricity provider partnerships in 2026.
What the numbers add up to
Sunrun‘s 2025 results tell a fairly coherent story. The company made a strategic call to prioritize battery storage, pushed its attachment rate to record levels, and closed the year holding nearly half the national residential market. Its cumulative installed base now represents 44% of all residential storage ever deployed in the U.S. — a network large enough to function as a meaningful grid resource, not just a consumer product line.
SEIA’s outlook points to continued growth, with Texas emerging as a new center of gravity. Sunrun’s early partnerships and strong year-over-year numbers there suggest it’s trying to run the same playbook it used in California before competitors get a foothold. Whether it can hold near-50% market share as the sector scales is genuinely unclear. But through 2026, no other residential installer is anywhere close.
Kelly is an experienced writer with 15 years of experience exploring the big stories that shape our world, from tech breakthroughs and space exploration to climate, energy, and the fascinating quirks of science. She has a talent for turning complex ideas into sharp, memorable insights that stay with readers long after they’ve finished reading.
