On October 15, 2026, the U.S. Energy Information Administration (EIA) reported that three U.S. regional transmission organizations (RTOs) set all-time hourly peak load records this summer. The figures are compiled in EIA's "Hourly Electric Grid Monitor" from data that each balancing authority reports on Form EIA-930.

The three grids that set records

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01

PJM (Eastern and Midwestern U.S.)

162.6 GW on July 2, 2026. 1.3% above the previous record (160.6 GW on June 23, 2025).

02

ERCOT (Texas)

91.1 GW on July 22, 2026. 6.5% above the previous record (85.5 GW on August 20, 2024).

03

SWPP (Central U.S.)

58.0 GW on July 27, 2026. 3.5% above the previous record (56.0 GW on August 21, 2023).

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ERCOT in Texas posted the largest increase, beating its previous record by 5.6 GW. PJM set a record for the second year running. All three grids peaked in July.

EIA's view: record heat

EIA also notes that Form EIA-930 data are published "as is" from each balancing authority's reports, that reporting issues may limit their quality, and that they may differ from figures published directly by each authority.

Other major grids came close to their records

According to EIA, grids that did not set records still came close (CAISO and ISO-NE within 2%, NYISO within 3% and MISO within 4%).

  • CAISO (California): 50.0 GW on September 9. The record is 51.1 GW on September 6, 2022
  • ISO-NE (New England): 25.3 GW on July 2. The record is 25.9 GW on June 24, 2025
  • NYISO (New York): 31.1 GW on July 2. The record is 31.9 GW on June 24, 2025 (NYISO itself cites 34.0 GW in 2013, before EIA began collecting hourly data)
  • MISO (Midwestern U.S.): 121.5 GW on June 30. This is the highest in EIA's hourly data, but below the 127.1 GW of July 20, 2011 that MISO reports

On July 2, the three eastern grids, PJM, ISO-NE and NYISO, all hit their peaks for the summer.

What it means for data center planners

  • Summer peaks set the baseline for interconnection terms: when grid operators decide on large-load connections, supply headroom at peak is the constraint. PJM is putting in place large-load rules for AI data centers, but if peak load keeps setting records, negotiations over connection terms and timing are likely to get tougher
  • Separate weather from structural drivers: EIA explains this summer's records by heat waves. If summers return to normal, peaks may come down, so reading how much data center load is adding requires looking at each grid's load forecasts as well
  • Prepare for peak hours: this summer's peaks were concentrated from early to late July. Joining demand response programs, or designing on-site generation and storage to limit grid draw at peak, can help speed up connection, alongside ways to get more out of existing grids

Referenced Fact Cards