The US Installed 20.2 GWh of Batteries in One Quarter, and 6.7 GW of Power Is the Figure to Read Beside It

The United States added a record 20.2 GWh of battery storage in the second quarter of 2026, according to the quarterly market outlook from the Solar Energy Industries Association (SEIA) and Benchmark Mineral Intelligence, which circulated again this week on Hacker News. The figure that matters here is not the energy total but the power rating beside it: ESS News reports the same quarter as 6.7 GW.

Divide one by the other and the average installation discharges for about three hours (20.2 GWh over 6.7 GW, my arithmetic). That is the shape of a grid that is buying batteries to move solar output into the evening peak, not to ride through multi-day outages.

The quarter in numbers

SEIA's own pages returned an access error to our fetch, so the figures below come from two outlets that quote the report: Electrek, published August 31, and ESS News, published September 1. Where they differ, both figures are given.

Segment, Q2 2026	Installed	Change
Utility-scale	about 18 GWh	n/a
Commercial and industrial	about 1.8 GWh	record for the segment (ESS News)
Residential	657 MWh	down 27% year on year

First-half installations reached 30.8 GWh, up 23% on the first half of 2025, per Electrek. Cumulative utility-scale capacity rose from 88 GWh to 165 GWh in 18 months, Electrek reports from the same outlook. Of Q2's utility-scale additions, 44% were paired with solar and 56% were standalone.

Arizona leads, and the three-state story is over

Arizona installed 6.2 GWh, a single-state record, Electrek reports, against 3.8 GWh in Texas and 3.6 GWh in California. Seven projects of GWh scale came online: four in Arizona, two in California and one in Utah. ESS News lists Arizona, California, Utah and Texas as each deploying more than 2.5 GWh.

1. Arizona6.2 GWh
2. Texas3.8 GWh
3. California3.6 GWh

Source: SEIA and Benchmark Mineral Intelligence outlook, as reported by Electrek, accessed 2026-10-30

Shan Tomouk, BESS and Energy Lead at Benchmark Mineral Intelligence, is quoted by Electrek saying "Energy storage is no longer just a California and Texas story anymore". Tim Pawlenty, SEIA's president and CEO, said "This record growth highlights that storage is a powerful reliability tool".

Homes fall back while data centres pull in storage

The 27% drop in residential installs is partly attributed in the report to the removal of the federal 25D tax credit, Electrek says, and Benchmark forecasts a 16% fall in residential installations for 2026 after a 56% jump in 2025. Commercial and industrial storage rose more than 52% year on year, which ESS News says the researchers tie mainly to data centres; analysts expect about 6 GWh more by year-end.

On the supply side, Electrek reports that Tesla brought its third Megafactory online in Texas, with a Megapack capacity of 50 GWh a year. For comparison with a different battery buyer, see our piece on the Rivian EDV 700 pack, and for the policy fights over industrial hardware, the robotics Section 232 proclamation.

The forecast and what would change it

Benchmark expects about 71 GWh installed in 2026, roughly 20% above the 59 GWh of 2025 (ESS News), and raised its cumulative forecast through 2030 by 11.5% to 683 GWh. With 30.8 GWh in the first half, a 71 GWh year needs about 40 GWh across the second half.

Three things would change this read: a falling average duration in the next outlook, which would mean peaking use replacing shifting use; a second consecutive quarter of residential decline beyond 27%; or interconnection delays in Arizona, where four of the seven large projects sit. All three are testable in the next quarterly release. The report's own caveat, per Electrek, is that it does not attribute project decisions to any administration.