US storage set a record 18.9GWh in Q2 even as installed megawatts fell
Victoria Shinder2 min readWood Mackenzie's Q3 2026 US Energy Storage Monitor, released on 23 September, reports that the US installed a record 5.4GW/18.9GWh of battery storage in the second quarter, according to Energy-Storage.News. The record is in energy, not power: installed megawatts fell 7% from a year earlier.
Longer durations explain the gap. Utility-scale projects reached 4.7GW/17.6GWh, with megawatt capacity down 8% year on year as major markets approach saturation, while durations kept rising, helped by California's first eight-hour battery and utility-contracted projects in Texas. The community, commercial and industrial segment deployed 48MW, back to typical levels after an unusual first quarter in California. Residential storage fell for a third straight quarter, down 15% to 676MW, which the firm attributes to tax credit phase-outs, consumer uncertainty and the shift to third-party ownership. California, Texas, Puerto Rico, Arizona and Illinois accounted for 88% of the quarter's capacity.
Looking ahead, Wood Mackenzie expects US installations to grow more than 50% in megawatt terms over five years, with utility-scale growing about 8% a year, driven by the need to balance large new loads and renewables. It says data-centre buildout is lifting the outlook across all segments. Residential storage is forecast to fall 4% in 2026 before growing about 9% a year from 2027. The figures differ from the rival SEIA and Benchmark Mineral Intelligence report, which counted 6.7GW/20.2GWh for the same quarter.
What it means
A record in gigawatt-hours alongside a fall in gigawatts is what a maturing market looks like. In the states where short-duration batteries have already captured the easy value, new projects are built longer to earn from a wider stretch of the day, and fewer megawatts are needed to shave the same peaks.
The two trackers' different totals are a reminder to compare like with like: methodologies differ, and a quarter can move between reports as projects are confirmed. The direction - longer batteries, saturating early markets and demand growth tied to large loads - is common to both.