Hot Weather Alert Issued for Aug. 25 for PJM’s Western and Southern Regions


PJM has issued an additional Hot Weather Alert for its Western and Southern regions for Aug. 25 as high temperatures and humidity continue to impact these areas. A Hot Weather Alert is also currently in effect for PJM’s Western Region for Aug. 24.

A Hot Weather Alert is a routine procedure PJM issues in anticipation of 90 degree weather and/or high humidity in order to prepare transmission and generation personnel and facilities for expected increases in electricity demand.

The Western Region in PJM is made up of the following transmission zones and control areas:

  • American Electric Power (AEP Ohio, Appalachian Power, Indiana Michigan Power and Kentucky Power)
  • American Municipal Power Transmission
  • ComEd
  • Cleveland Public Power
  • Dayton Power & Light
  • Duke Energy Ohio and Duke Energy Kentucky
  • Duquesne Light Company
  • East Kentucky Power Cooperative
  • FirstEnergy South – aka Allegheny Power Systems (West Penn Power, Mon Power, Potomac Edison)
  • FirstEnergy West – aka American Transmission Systems, Inc. (Penn Power, Ohio Edison, The Illuminating Company and Toledo Edison)
  • ITC Interconnection, LLC
  • Ohio Valley Electric Corporation

The Southern Region in PJM is made up of Dominion’s service area.

As of 9 a.m. Aug. 24, PJM expects to serve a forecasted load across the RTO of around 131,000 MW on both Aug. 24 and Aug. 25.

The forecasted summer peak demand for electricity is approximately 156,000 MW, but PJM has performed reliability studies at even higher loads – in excess of 163,000 MW.

PJM’s current peak demand for this summer occurred July 27 and was 148,000 MW. The all-time recorded peak electricity demand on PJM was 165,563 MW on Aug. 2, 2006.

A dedicated team of operators uses sophisticated technology to balance supply and demand and direct the power grid 24/7 from PJM’s control rooms. They prepare multiple potential scenarios that could be impacted by weather, emergency conditions or equipment failure. They adjust resource output with changes in demand and ensure that no transmission lines or facilities are overloaded. The team also watches for unusual conditions and reacts to them to protect the electricity supply. Read more about how PJM forecasts electricity demand on the PJM Learning Center.