Update: Hot Weather Alerts Extended Through Sunday for Most of PJM Footprint


Updated July 19 at 2:10 p.m. Eastern.

PJM has issued an additional Hot Weather Alert for Sunday, July 21, for the entire service region except for the ComEd transmission zone. Hot Weather Alerts are already in effect for the entire PJM footprint through Saturday.

PJM currently expects electricity use to peak between 150,000 MW and 152,000 MW on Friday, July 19. That is in line with PJM’s forecast in May as the peak for this summer.

PJM served a preliminary peak load of about 144,000 MW on Wednesday, July 17, and over 138,000 MW on Thursday, July 18. Demand was less than expected due to actual temperatures being lower than forecast.

The preliminary peaks were calculated daily from raw telemetry data and are approximate values for informational purposes only.

The hottest weather is expected on Saturday, but electricity use is generally lower on weekends. Sunday’s weather is also expected to be in the high 90s in many places except Northern Illinois, where temperatures are expected to fall into the 70s.

Original Story

Hot Weather Alerts Expanded and Extended Through Saturday

PJM Interconnection has issued Hot Weather Alerts for its entire footprint for Thursday, July 18, through Saturday, July 20. PJM previously issued a Hot Weather Alert for the Mid-Atlantic and Dominion regions of the footprint for Wednesday, July 17.

Temperatures are forecast to be in the mid-90s Wednesday for most of the Eastern Seaboard states in the region served by PJM, from New Jersey to North Carolina. Heat and humidity are expected to build throughout the rest of the week across the entire PJM footprint of 13 states and the District of Columbia.

Extended heat and humidity drives up demand for electricity. PJM expects electricity use to peak at around 152,000 MW on Friday, July 19.

PJM has 183,454 MW of committed capacity to meet customer demand. One megawatt can power about 800 homes.

Last summer’s peak demand was 150,830 MW on Aug. 28. PJM’s all-time highest power use was 165,563 MW in the summer of 2006.

What Is a Hot Weather Alert?

A Hot Weather Alert helps PJM and its utility partners coordinate the flow of energy and avoid capacity problems on the grid.

It prepares transmission and generation personnel and facilities for extreme heat and/or humidity that may cause capacity problems on the grid. PJM works with transmission and generation operators to determine whether they can defer or cancel any maintenance or testing on their facilities.

How PJM Ensures Reliable Electricity in Hot Weather

PJM meets electricity needs by procuring enough resources to satisfy peak demand, plus required reserves, at the lowest cost through its competitive markets. PJM works with its members to ensure that power flows where it is needed and holds resources, such as generating plants, to strict standards to deliver electricity as promised.

PJM also has resources on reserve to cover generation that is unexpectedly unavailable or demand that is higher than forecasted.

Track Operations in Real Time: 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. PJM Interconnection, founded in 1927, ensures the reliability of the high-voltage electric power system serving 65 million people in all or parts of Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and the District of Columbia. PJM coordinates and directs the operation of the region’s transmission grid, which includes over 84,236 miles of transmission lines; administers a competitive wholesale electricity market; and plans regional transmission expansion improvements to maintain grid reliability and relieve congestion.