About 16% of new US utility solar this year comes paired with batteries, up from 2% in 2017

Developers of American utility-scale solar are bolting batteries onto their projects at a pace that would have sounded implausible a decade ago. According to the U.S. Energy Information Administration, about 16% of the new solar capacity added in 2026 is co-located with operable battery storage, compared with 2% in 2017. The share has multiplied roughly eightfold in nine years.

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The figure arrived in an October 30 note from the agency’s analysts, drawn from operator-reported data through September. Their wording is “over 16%,” which is why the number reads as a floor, and the same data point to a still higher share by the end of the year because several paired projects are scheduled to come online in the fourth quarter.

The finding appears in the EIA’s Today in Energy item on solar and battery pairing, and a companion version of the same release spells out the comparison with 2017 and the forward-looking numbers. Both rest on the agency’s monthly generator inventory, form EIA-860M, a survey of units at plants with at least 1 megawatt of combined nameplate capacity. The September 2026 edition was released October 23, and the next arrives November 24.

From 2% in 2017 to more than 16% in 2026

The 2017 baseline is small because batteries were then a niche add-on. Lithium-ion packs cost far more, few markets paid for evening capacity and most solar farms were built to push every kilowatt-hour straight to the grid. By 2026 the arithmetic had flipped in several regions, and the EIA counts the capacity-weighted result: of every 100 megawatts of solar that entered service this year, a little over 16 came with a battery at the same plant.

Plans extend the trend. Reported schedules for solar coming online in the last three months of 2026 imply a 19% co-location share for the full year, and developers’ filings for 2027 and 2028 put the share above 30%. Those later figures are intentions, not commissioned plants, and the EIA’s own inventory notes that capacity values are preliminary estimates that can change from month to month.

Selling into the evening price curve

The agency’s explanation is economic. A co-located plant can send solar output either to the grid or into storage depending on wholesale prices, which tend to fall when solar output is high and climb as it fades. A battery lets the owner hold midday energy for the evening ramp, when prices usually rise, instead of selling into the glut that its own panels help create.

That logic is already visible in the biggest sites. In a separate EIA study of battery growth, the agency describes Bellefield Solar and Energy Storage Farm in California, which began operating in December 2025 with 500 megawatts of photovoltaics and 500 megawatts of storage and plans to double both by November 2026. Nevada’s Gemini Solar Hybrid pairs 690 megawatts of panels with 380 megawatts of batteries, and Florida’s Manatee Solar Energy Center combines 75 megawatts of solar with 409 megawatts of storage.

The EIA’s review of battery storage capacity found utility-scale batteries growing at an annual average of 70% over the last three years, from 43.6 gigawatts at the end of 2025 to nearly 52 gigawatts by midyear after 8.3 gigawatts of additions in the first half. Operators told the agency they plan roughly 54 gigawatts more over the next two and a half years, with 14 gigawatts in the second half of 2026, 26 gigawatts in 2027 and 14 gigawatts in 2028. Solar plants host the largest of these battery units, which is why the two trends are hard to separate in the data.

Southwest states set the national average

Geography explains much of the national number. Solar represents 13% of total U.S. utility-scale generating capacity, and 18% of that solar is paired with batteries. California, Arizona, New Mexico and Nevada each show co-location shares more than double the national average, and these Southwest states also carry above-average solar shares of their total capacity. The pairing is concentrated where midday oversupply is deepest and evening demand peaks sharply.

In planning data published last winter, the EIA reported that developers expected a record 86 gigawatts of new generating capacity in 2026, including 43.4 gigawatts of solar and 24 gigawatts of battery storage. Texas projects such as Tehuacana Creek 1, listed with 837 megawatts of solar and 418 megawatts of storage, show the model spreading beyond the Southwest. The same planning release listed 11.8 gigawatts of wind and 6.3 gigawatts of natural gas, a mix in which solar and storage together account for roughly four-fifths of expected additions.

Capacity share versus energy delivered

The statistic counts megawatts, not energy. Latitude Media, which reproduced the data on the day of release, noted that the figures describe capacity shares rather than generation shares, so they say nothing about how many kilowatt-hours actually flow through batteries. The EIA adds a methodological caveat: solar and battery units at one plant often enter service at different times, so the agency uses the EIA-860 and 860M records to identify co-located plants rather than relying on a single in-service date.

The open question is how much of the 30%-plus planned for 2027 and 2028 survives interconnection queues and equipment lead times. The Latitude Media write-up of the data carries the same projections, and the next EIA-860M release on November 24 will show whether the fourth-quarter additions lift 2026 toward the 19% the agency’s operator filings imply.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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