The first major U.S. heat wave of summer 2026 pushed a heat dome across the Central and Eastern U.S. in the days around July 4th, with temperatures regularly above 100°F. Hourly midday load on PJM, the nation’s largest grid operator, peaked near 160 GW, approaching the all-time record of 165,563 MW set in 2006.
The incremental supply came almost entirely from dispatchable generation. Nuclear, coal, and natural gas delivered 88% of the total, and the ramp concentrated in the two fuels that can be called on demand: coal rose from 14.3 to 24.2 GW (up roughly 69%) week-over-week, and gas from 43.6 to 55.0 GW (up 26%). Solar and wind held flat at 7.5 GW. The load event also triggered DOE’s third Section 202(c) emergency order of 2026, waiving plant emissions limits as wholesale prices topped $2,000/MWh.