Update: Hot Weather Alerts Extended for PJM Mid-Atlantic Region and Dominion


July 20 Update

PJM has issued additional Hot Weather Alerts for its Mid-Atlantic region and Dominion for July 21 and 22 amid continued hot weather along the Atlantic Coast.

Hot Weather Alerts are issued when temperatures are expected to exceed 90 degrees Fahrenheit with high humidity, driving up demand for electricity. High temperatures are expected to remain in the 90s with higher heat indexes anticipated.

The Mid-Atlantic region includes the Atlantic City Electric, Baltimore Gas & Electric, Delmarva Power, Jersey Central Power & Light, Met-Ed, Penelec, PECO, PEPCO, PPL Electric Utilities, PSE&G and Orange & Rockland: Rockland Electric Company transmission zones.

Over the weekend, PJM served the following preliminary approximate loads:

  • Friday, July 17: 138,112 MW between 5–6  p.m. (Eastern)
  • Saturday, July 18: 138,755 MW between 5–6 p.m. (Eastern)
  • Sunday, July 19: 136,363 MW between 5–6 p.m. (Eastern)

Preliminary integrated hourly loads are calculated daily from raw telemetry data and are approximate for informational purposes only.

PJM had previously issued alerts for July 18–20 for the entire region PJM serves.

July 17 Post: PJM Issues Hot Weather Alerts for July 18–20

PJM has issued a Hot Weather Alert for the region it serves for July 18–20 with the onset of a heat wave across much of the Midwest and Atlantic Coast.

Hot Weather Alerts are issued when temperatures are expected to exceed 90 degrees Fahrenheit with high humidity, driving up demand for electricity. Temperatures are expected to be in the 90s through the weekend and into Monday for much of the PJM footprint, which encompasses 13 states, from Illinois to North Carolina to New Jersey, and includes the District of Columbia.

If temperatures are as predicted for Monday, PJM could approach the summer forecasted peak of approximately 148,000 MW. Recent hot weather in the PJM region resulted in preliminary peaks in the 142,000–145,000 MW range.

Last summer’s peak demand measured more than 151,000 MW on July 19. (One megawatt can power approximately 800 homes.)

Read more about how PJM is prepared to meet the demand for electricity this summer and maintain system reliability.

Pandemic Impacts

Since March, with the onset of business closures and social distancing restrictions related to the coronavirus pandemic, both weekday peaks and total energy use have come in at about 8 percent less than what would have been anticipated in a typical year.

This impact has eased in recent weeks as some businesses have begun to reopen. Since mid-June, weekday peaks have been down approximately 2 percent on average. Over the same time period, overall energy use on weekdays is down roughly 5 percent due to COVID-19-related impacts.

What Is a Hot Weather Alert?

A Hot Weather Alert prepares transmission or generation facilities for extreme hot or humid conditions which may pose capacity issues for the grid. To reliably serve demand, transmission and generation operators are asked to identify any maintenance or testing on equipment that can be deferred or canceled so as to make all equipment and resources available. PJM’s reserve resources are available to cover for generation that may be unexpectedly unavailable or to help meet demand that is higher than forecasted.

Tools to Track PJM Operations

Track PJM’s markets and operations in real time on the Markets and Operations page on PJM.com or through the PJM Now app for iPhone and Android. Learn more about how PJM prepares for summer operations on the Learning Center.