Heat Dome Regions (Northeast, Midwest and Texas) Power Generation (GW)

The first U.S. summer heat wave of 2025 arrived early, as a heat dome settled over Mid-Continent, Mid-Atlantic, and Northeastern states for almost a week in late June, with temperatures peaking on June 23rd. Electricity demand rose sharply in response, particularly across the regions served by five regional transmission operators (RTOs): ERCOT (Texas), MISO (Midwest), ISNE (New England), NYISO (New York State), and PJM (Virginia, New Jersey, Maryland, Ohio, and parts of Indiana and Illinois).

Combined power generation across these regions reached 401,000 MW between 5pm and 7pm, accounting for almost 55% of total U.S. generation on that day.

Examining average hourly generation across these RTOs for the period from June 20th to June 28th, dispatchable generation—nuclear, coal, natural gas, and hydro—supplied more than 81% of electricity production. Natural gas alone provided 42.7%.

Intermittent generation from solar and wind accounted for 17.1% of output, of which wind contributed 11.3%.

From the EPRINC Chart of the Week archive.