US Residential Solar Battery Attachment Rate Rises to 37% in 2025, LBNL Finds
Batteries were paired with 37% of new U.S. residential solar installations in 2025, up from 25% in 2024, according to a dataset released October 3, 2026 by the Lawrence Berkeley National Laboratory (LBNL), a U.S. Department of Energy national laboratory. The figures come from LBNL’s latest “U.S. Distributed Solar and Storage” data update, which tracks roughly 5.3 million distributed solar and solar-plus-storage systems installed nationwide through the end of 2025, including an estimated 450,000 systems added last year alone — a sample LBNL says represents about 93% of the U.S. market. pv magazine reported on the findings the same day.
California still leads, but the national gain is coming from elsewhere
California and Hawaii have for years posted the highest residential battery attachment rates in the country, a pattern LBNL’s data confirms held through 2025. California’s rate reached 74% of new residential solar installations last year, up from 58% in 2024. But the more consequential shift, in terms of its effect on the national average, happened outside those two states. Across the rest of the country combined, the share of new residential solar installations that also included a battery rose to 17% in 2025, more than double the 7% recorded in 2024. LBNL’s data flagged Arizona and Texas as states where the increase was particularly large.
Net billing rules are spreading the economics that made batteries necessary in California
The underlying driver, per LBNL, is the way utilities compensate homeowners for solar power sent back to the grid. California’s Net Billing Tariff, widely known as NEM 3.0, has been in effect since April 2023 and substantially cut the value of exported solar electricity. That change made storing power for later use, rather than exporting it, the more economical choice for many California homeowners, pushing attachment rates higher. LBNL’s report notes that similar net-metering and time-of-use rate redesigns are now appearing in other states, and the data suggest those changes are starting to produce the same effect elsewhere that NEM 3.0 produced in California, albeit from a much lower starting point.
Commercial solar customers are adding batteries too, just far more slowly
Non-residential, or commercial, solar installations followed the same direction but a much flatter curve: 11% of new commercial systems included a battery in 2025, up from 7% in 2024, LBNL found. The comparatively small increase suggests that the billing and rate pressures reshaping homeowner decisions have not yet pushed commercial solar customers toward storage anywhere near as forcefully, likely a reflection of how differently businesses are billed for electricity consumption and exports compared with households.
Backup power and bill management are converging for homeowners
For many households, the appeal of a battery is no longer only about riding out a storm. Under net billing tariffs like NEM 3.0, a battery lets a homeowner shift self-generated solar power away from the midday hours, when exporting it is worth little, toward the evening peak, when utilities often charge the most under time-of-use rate plans. That dual role, backup power during an outage and bill management the rest of the year, is changing how installers position storage alongside solar, as a standard part of the offer rather than an optional add-on sold separately. LBNL’s data does not break out how installers are marketing systems, but the steady rise in attachment rates across states adopting similar rate structures is consistent with batteries shifting from a niche upsell to a routine component of a residential solar quote.
The batteries themselves are getting more powerful, not bigger
LBNL’s update also tracked how the batteries being installed are changing in a separate dimension: power output rather than storage size. The median residential battery installed in 2025 held 13.5 kWh of energy capacity — essentially unchanged from 2024, meaning a typical battery can run a home’s essential loads for about as long as before. Its discharge, or power, capacity told a different story: the median jumped to 11.4 kW in 2025, up sharply from 6 kW a year earlier. LBNL attributes much of that increase to the wider rollout of the Tesla Powerwall 3, a unit built for substantially higher power output than its predecessor. The distinction matters for homeowners: energy capacity determines how long a battery can keep the lights on, while power capacity determines how much it can run at once, such as an air conditioner or an EV charger. For a sense of scale on the other end of the market, TDE has explained how the Tesla Megapack is built for grid-scale duty in megawatts rather than kilowatts, but the residential trend toward higher-output hardware echoes a broader industry push toward more capable battery systems at every scale.
Growth in battery attachment is arriving as the solar market itself cools
The attachment-rate increase is unfolding against a difficult backdrop for new U.S. residential solar overall. The federal residential solar tax credit, known as 25D, expired at the end of 2025 under the 2025 tax law, removing an incentive that had supported homeowner solar economics for nearly two decades. At roughly the same time, Section 232 import tariffs have pushed U.S. solar module prices up by more than 40%, as TDE has reported. Neither development explains the rise in battery attachment itself — LBNL ties that squarely to net billing and rate design rather than tariff policy — but together they point to a residential solar market where overall unit volumes face real headwinds even as each new system is, on average, more likely to include storage hardware than before. That pattern of rising value per installation, even with softer sales, is visible on the supply side as well, where battery manufacturers such as Fluence have been locking in multiyear component supply deals to secure the hardware needed to keep up with storage demand. That shift is also reshaping how some installers package their offers, bundling storage into the base solar quote rather than presenting it as a separate option.
Sources
Lawrence Berkeley National Laboratory, “U.S. Distributed Solar and Storage” 2026 data update — primary source for the attachment-rate, battery capacity and installation-count figures cited throughout this article. Read the report (PDF).
pv magazine, “Battery storage paired with 37% of new U.S. residential solar systems in 2025,” October 3, 2026 — independent coverage confirming the report’s release and its headline findings. Read the article.
Illustrative image. Photo: Dr. Chinchu C., CC BY 4.0, via Wikimedia Commons — source
