PJM, ERCOT and SPP All Set Summer Peak-Load Records in 2026, EIA Data Show

Three of the largest power grids in the United States — PJM Interconnection, the Electric Reliability Council of Texas (ERCOT) and the Southwest Power Pool (SPP, which the U.S. Energy Information Administration labels SWPP in its data) — each posted their highest hourly electricity demand on record this summer, according to EIA figures published on October 15. PJM peaked at 162.6 gigawatts (GW) on July 2, ERCOT reached 91.1 GW on July 22, and SPP hit 58.0 GW on July 27, as regional heat waves pushed air-conditioning load higher across a grid footprint that reaches well over half the U.S. population.

Three Grids, Three New Highs

The EIA figures, drawn from Form EIA-930 hourly data reported by balancing authorities and presented through the agency’s Hourly Electric Grid Monitor, show each grid’s new peak exceeding its previous high by a measurable margin. PJM’s 162.6 GW topped its prior record of 160.6 GW from June 23, 2025, by about 1.3%. ERCOT’s 91.1 GW beat its August 20, 2024 record of 85.5 GW by roughly 6.5%, the largest jump of the three. SPP’s 58.0 GW edged past its August 21, 2023 mark of 56.0 GW by about 3.5%.

EIA cautioned that balancing authorities report their best available values at the time of submission, so the figures can be revised, and data published directly by grid operators may differ slightly from the Form EIA-930 series used in the comparison.

Four Grids Came Close, but Didn’t Break Records

Not every major grid set a new mark. The California Independent System Operator (CAISO) reached 50.0 GW on September 9, within about 2% of its September 2022 record of 51.1 GW. ISO New England peaked at 25.3 GW on July 2, just under its June 2025 record of 25.9 GW. The New York ISO hit 31.1 GW on July 2, short of its 31.9 GW mark from June 2025 — and further still from the 34.0 GW all-time peak NYISO has recorded for 2013, before EIA’s current hourly series began. The Midcontinent ISO (MISO) reached 121.5 GW on June 30, the highest figure in EIA’s Hourly Electric Grid Monitor for that system, but below the 127.1 GW record MISO cites on its own fact sheet, set in July 2011.

Heat, Growth and a Grid Under Pressure

EIA linked most of the new peaks to regional heat waves during what it described as the hottest summer on record nationally. But the records also land amid a broader surge in electricity demand that is reshaping how U.S. grid operators plan for the years ahead. PJM in particular has become a focal point for that debate: the grid operator serves a fast-growing cluster of data centers, and federal regulators recently rejected the core of PJM’s plan for connecting new large data-center loads to the system, leaving open how the grid will absorb demand growth without compromising reliability for existing customers.

Utilities serving PJM territory and beyond have been moving to add capacity on multiple fronts to keep pace. American Electric Power agreed to buy up to 1.6 GW of fuel-flexible linear generators from Mainspring Energy for deployment through 2034, while Black Hills Corporation committed to a new gas plant and microgrid to power a Google data center in Wyoming. States are also leaning on storage and renewables: Maryland’s regulators awarded 440 MW of battery storage capacity in the first round of a new procurement, though that fell short of the state’s 800 MW target.

Why the Numbers Matter for Grid Planning

Peak-demand records are more than a statistical curiosity for system operators. Reserve-margin requirements, generation-adequacy assessments and transmission-expansion plans are all built around expected peak load, and a grid that repeatedly exceeds its planning assumptions has less cushion when generators trip offline or extreme weather hits on both the supply and demand side at once. ERCOT’s 6.5% jump is the sharpest of the three, continuing a pattern of rapid load growth in Texas tied to population gains, industrial electrification and, increasingly, data-center and crypto-mining demand. PJM’s narrower 1.3% increase still matters because it occurred on a system already stretched by load growth from Virginia’s data-center corridor, a dynamic regulators and the grid operator are actively trying to manage through new interconnection rules.

Sources

• U.S. Energy Information Administration, “PJM, ERCOT, and SWPP all set peak load records this summer,” Today in Energy, October 15, 2026 — for all peak-load figures, dates, prior records and the Form EIA-930 methodology. eia.gov
• Utility Dive, reporting on EIA load data and ERCOT’s record highs, October 2026 — for independent corroboration of the trend. utilitydive.com

Illustrative image. Photo: Frans Berkelaar, CC BY 2.0, via Wikimedia Commons — source