Texas Batteries Nearly Doubled Their Output at the Evening Peak This Summer

Batteries on the ERCOT grid supplied an average of 8,555 MW in the hour of highest net load each day from July to September 2026, up from 4,818 MW in the same months of 2025. Net load, meaning demand minus wind and solar output, averaged 63,848 MW in that hour, 4.9 GW higher than last summer. The added battery output equals about 76% of that increase. These are TEI calculations from the hourly data ERCOT reports to the US Energy Information Administration on Form EIA-930.

Gas plants produced 39,445 MW on average in the same hours, 118 MW more than in 2025. The peak usually fell at hour ending 21, between 8 and 9 p.m. Central time. On the hardest single hour of the summer, 22 July at hour ending 21, batteries delivered 11,316 MW.

ERCOT's operational battery fleet stood at 21,537 MW in its September 2026 capacity report, against 15,485 MW a year earlier. Output at the net-load peak rose about twice as fast as installed capacity. The comparison spans the 5 December 2025 launch of Real-Time Co-optimization plus Batteries, which changed how storage is dispatched and reported.

ERCOT's August reliability outlook moved the highest-risk hour to hour ending 22 as large loads keep evening demand high. In this summer's data, battery output fell to about 1.5 GW by hour ending 23 and gas output after 10 p.m. rose more than it did at the peak. Our analysis covers the hourly profile, midday charging and the limits of comparing the two years.