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Power Grid Operators Respond to High Temperatures, Spike in Power Demand

Grid operators in recent days have been responding to increases in power demand spurred by scorching weather across portions of the U.S.

The PJM Interconnection on Aug. 22 said that it had extended a Hot Weather Alert for its Western Region to Aug. 24 as hot and humid weather continues in that region. A Hot Weather Alert was in effect for Aug. 23 for the same region.

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.

Temperatures in PJM’s Western Region were forecast to exceed 90 degrees with high humidity.

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

As of 9 a.m. Aug. 23, PJM expected to serve a forecasted load of around 128,000 MW on Aug. 23 and around 131,000 MW on Aug. 24.

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.

Meanwhile, the Southwest Power Pool on Aug. 22 said that due to, among other things, increased uncertainty in potential capacity adequacy with continued high temperatures, SPP was extending its current Conservative Operations Advisory for the entire SPP Balancing Authority footprint in the eastern interconnection through 9:00 p.m. CT Friday, August 25.

SPP said it also remained under a previously declared Resource Advisory in effect through Friday, August 25, and a previously declared Weather Advisory also in effect through Friday, August 25.

It noted that none of these advisories require the public to conserve energy.

SPP’s service territory set a new record for electricity use on August 21 at 4:27 p.m. CT when energy demand peaked at 56,184 MW.

The Midcontinent ISO said that it was declaring a Maximum Generation Emergency Alert effective from Aug. 24, 12:00 EST until Aug. 24, 10:00 pm EST for the MISO Balancing Authority Area.

The reason for the alert is because of high forecasted load, above normal temperatures, and additional resource uncertainty.

Elsewhere, the Electric Reliability Council of Texas has issued a Weather Watch for August 23-27 due to forecasted higher temperatures, higher electrical demand, and the potential for lower reserves. Grid conditions are expected to be normal.

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