Through September 2026, more than 16% of the utility-scale solar capacity added in the United States came with an operable battery on site, up from 2% in 2017. The U.S. Energy Information Administration reported the figure on October 30, 2026, in a Today in Energy note by Glenn McGrath and Alex Mey. The pairing has moved from a rarity to a standard option in under a decade.
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If operators finish the projects they have reported for the last three months of the year, the share for all of 2026 rises to 19%. Plans for 2027 and 2028 push it above 30%. Those later numbers come from developers’ reported schedules, so they describe intentions rather than a forecast from the agency. Reaching 19% for the year means the fourth quarter has to run well above the pace of the first nine months, which sit just over 16%, and year-end commissioning dates can move.
The EIA numbers behind the 16% and the 2% in 2017
The analysis draws on EIA-860M, the monthly update to the agency’s annual generator survey. According to the EIA’s October 30 analysis, solar photovoltaic plants make up 13% of total U.S. utility-scale generating capacity as of September 2026, and 18% of that solar fleet is co-located with battery storage. The two shares differ because the older fleet, built mostly without batteries, drags the stock figure below the share of this year’s additions.
The note does not publish gigawatt totals for the paired plants or the storage capacity in megawatt-hours, and the charts that carry year-by-year additions are not reproduced in the text. That matters for reading the 16%: it is a share of capacity added, so a small year of solar building and a large one would produce the same percentage with very different amounts of hardware behind it.
The 2% starting point has context. An earlier EIA note put battery storage operating in the United States at the end of 2020 at 1.5 gigawatts, and only about 29% of it sat with other generators; the other 71% was standalone. The 2026 figure measures something narrower, the batteries attached to new solar plants, but both point the same way: batteries first stood alone, and developers have since learned to build them into the solar site itself.
The Southwest sets the pace
California, Arizona, New Mexico and Nevada have a share of solar generation co-located with batteries more than double the national average, the EIA says. Those states also rely more heavily on solar overall, with higher solar shares of total capacity, which gives batteries more midday energy to move into the evening peak.
Texas, by contrast, is not on the EIA’s list of high co-location states even though it dominates the pipeline. PV Tech’s summary of the agency’s outlook put Texas at about 40% of new 2026 solar capacity and 53% of new battery storage, and singled out Tehuacana Creek 1, an 837-megawatt solar project paired with a 418-megawatt battery system, as the largest solar project expected online this year.
Why developers keep bolting batteries onto solar
An earlier EIA analysis from September 2021 found that 9.4 gigawatts, or 63%, of 14.5 gigawatts of planned U.S. battery capacity would sit with solar plants, and that over 90% of planned battery capacity outside the organized power markets would be paired with solar. The agency gave two reasons: solar’s regular daily output suits batteries that can only discharge for limited periods before recharging, and pairing them lets projects use the federal Investment Tax Credit available for solar.
The wider build-out gives the pairing room to grow. pv magazine reported in February that the EIA expected 86 gigawatts of new U.S. utility-scale capacity in 2026, including 43.4 gigawatts of solar, up 60% from the 27.2 gigawatts added in 2025, and 24.3 gigawatts of batteries against a 15-gigawatt record the year before. On the storage side, the EIA’s August 2026 update counted 8.3 gigawatts of batteries added in the first half and 14 gigawatts planned for the second.
What remains unanswered is how much of that battery capacity will actually shift solar output into the evening, since the EIA’s note measures co-location, not how plants are dispatched. The agency has the plant-level data to answer that, and it has not yet said whether it will.
The projects behind the percentage vary widely in ratio. The EIA’s August note described the Bellefield Solar and Energy Storage Farm in California, which began operating in December 2025 with 500 megawatts of solar and 500 megawatts of storage and plans to double both by November 2026; Manatee Solar Energy Center in Florida, with 75 megawatts of solar and 409 of storage; and Gemini Solar Hybrid in Nevada, with 690 megawatts of solar and 380 of storage. A plant counts as co-located whether its battery is a fraction of its solar capacity or several times larger.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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