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US Lower 48 power demand peaks at 498,372 MWh, above forecast, as gas output jumps

Hourly electricity demand in the Lower 48 US states peaked at 498,372 megawatthours (MWh) on Tuesday evening, US time. That was above the day-ahead forecast, and natural gas plants supplied most of the extra power.

A data update from FactIQ, written from Energy Information Administration figures. What is FactIQ?

Key figures

Lower 48 hourly electricity demand peak, first UTC hour of Oct 21 (Tuesday evening, US time)
498,372 MWhup from 489,828 the day before and 464,147 two days before2026-10-202026-10-22Hourly Electricity Demand for the Lower 48 United States (UTC Time)
Day-ahead demand forecast for the Lower 48 for the same hour
490,205 MWhactual demand came in about 8,000 MWh above the forecast2026-10-212026-10-23Day-Ahead Electricity Demand Forecast for United States Lower 48 Region, Hourly (UTC Time)
Lower 48 hourly electricity generation from natural gas, peak hour on Oct 20
207,489 MWhOct 19's highest hour was 192,1322026-10-192026-10-21Hourly Net Electricity Generation from Natural Gas in the United States Lower 48 States (UTC Time)

Demand rose each evening this week and beat the forecast

Hourly electricity demand measures how much power customers use in an hour. It shows how hard the grid is working. Across the Lower 48 states, demand peaked at 498,372 megawatthours (MWh) in the first hour of Oct 21 in Coordinated Universal Time (UTC), which is Tuesday evening in the US. The same evening hour was 489,828 MWh the day before and 464,147 MWh two days before. The peak came in about 8,000 MWh above the US Energy Information Administration's (EIA) day-ahead forecast of 490,205 MWh for that hour.

Natural gas plants supplied most of the extra power

  • Lower 48 gas-fired generation reached 207,489 MWh in one hour on Oct 20.
  • On Oct 19, the highest hour was 192,132 MWh.
  • On Oct 18, evening hours were about 147k–164k MWh.

Regional patterns and revisions were routine

PJM Interconnection, a large regional grid operator, shows two daily peaks, one in the morning and one in the evening. This pattern is usual in cooler weather. Its hourly highs were about 94k MWh.

Several western utilities filled in partial early figures for Oct 20:

  • Arizona Public Service: 2,214 to 5,818 MWh.
  • Los Angeles Department of Water and Power (LADWP): 603 to 3,022 MWh.
  • Bonneville: 5,959 to 7,424 MWh.

These revisions raised Northwest Region demand by up to ~2,600 MWh in one hour. EIA also revised Idaho Power's Oct 10–11 generation and demand. For example, generation went from 1,284 to 1,306.26 MWh and demand went from 1,556 to 1,578.26 MWh.

Source: Energy Information Administration. See all EIA data in FactIQ.

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