PJM, ERCOT, and SWPP all set peak load records this summer

Data source: U.S. Energy Information Administration, Hourly Electric Grid Monitor
Note: Data are the highest hourly load for a given day. ISO=independent system operator, ERCOT=Electric Reliability Council of Texas, SWPP=Southwest Power Pool

Three regional transmission organizations (RTOs) set records for peak hourly load this past summer, according to data reported on Form EIA-930 and presented in the Hourly Electric Grid Monitor:

PJM peaked at 162.6 gigawatts (GW) on July 2, 2026, 1.3% higher than the pre-2026 peak of 160.6 GW on June 23, 2025.

The Electric Reliability Council of Texas (ERCOT) peaked at 91.1 GW on July 22, 2026, 6.5% higher than the pre-2026 record of 85.5 GW on August 20, 2024.

The Southwest Power Pool (SWPP) peaked at 58.0 GW on July 27, 2026, 3.5% higher than the pre-2026 peak of 56.0 GW on August 21, 2023.

Most of these peaks occurred during regional heat waves, amid the hottest summer on record nationally, which drove up cooling demand.

Data source: U.S. Energy Information Administration, Hourly Electric Grid Monitor
Note: : ISO=independent system operator, MISO=Midcontinent Independent System Operator, CAISO=California Independent System Operator, NYISO=New York Independent System Operator, and ISO-NE=Independent System Operator New England

The California Independent System Operator (CAISO) and the Independent System Operator for New England (ISO-NE) came within 2% of their previous records. The New York Independent System Operator (NYISO) was within 3% of its previous record load, and the Midcontinent Independent System Operator (MISO) was within 4%, according to Form EIA-930:

CAISO reached 50.0 GW on September 9, 2026, below its record high of 51.1 GW reached on September 6, 2022.

ISO-NE reached 25.3 GW on July 2, 2026, below its record of 25.9 GW on June 24, 2025.

NYISO reached 31.1 GW on July 2, 2026, below its previous record of 31.9 GW on June 24, 2025 (NYISO reports a record of 34.0 GW set in 2013, before we collected hourly data).

MISO peaked at 121.5 gigawatts (GW) on June 30, 2026, the highest in our Hourly Electric Grid Monitor but below the previous peak of 127.1 GW on July 20, 2011, as reported by MISO.

Data from Form EIA-930 is reported to us by each balancing authority (BA) and is made available "as-is". The data BAs report on the Form EIA-930 represent best values at the time of reporting, but various reporting issues may limit the quality of these data. Data published directly by BAs may differ from the data in Form EIA-930.

Principal contributor: Alex Mey