PJM has issued a Hot Weather Alert for May 20–21 for its Mid-Atlantic and Southern regions in anticipation of unusually hot spring weather.
A Hot Weather Alert helps to prepare transmission and generation personnel and facilities for extreme heat and/or humidity that may cause capacity problems on the grid.
Temperatures are expected to go above 90 degrees, which drives up the demand for electricity. The unseasonably hot May temperatures are anticipated while some generation and transmission facilities are offline for long-term maintenance projects (a normal occurrence during the spring and fall when demand is typically lower). PJM is working closely with transmission and generation operators to place some equipment back in service ahead of the hot weather.
As of May 19, PJM has forecast a peak of approximately 119,000 MW for May 20 and approximately 122,000 MW for May 21. PJM’s all-time one-day highest power use was recorded in the summer of 2006 at 165,563 MW. One megawatt can power about 800 homes.
The Mid-Atlantic region includes the Atlantic City Electric, Baltimore Gas and Electric, Delmarva Power & Light, Jersey Central Power & Light, Met-Ed, Penelec, PECO Energy, Pepco, PPL Electric Utilities, PSE&G, and Orange & Rockland (Rockland Electric Company) transmission zones.
The PJM Southern region consists of Dominion Virginia Power’s service territory.
Preparing for Hot Weather
PJM is prepared to serve a forecasted summer peak demand for electricity of approximately 149,000 MW but has performed reliability studies at even higher loads – in excess of 157,000 MW. PJM has approximately 185,000 MW of installed generating capacity available to meet customer needs, with sufficient resources available in reserve to cover generation that is unexpectedly unavailable or for other unanticipated changes in demand.
Last year’s peak demand was approximately 149,000 MW.
In preparation for summer, PJM has worked with transmission and generation owners throughout the spring to ensure that critical maintenance and system improvements were completed. To stay ahead of any fuel-related supply chain concerns, PJM continues to conduct fuel inventories every two weeks and monitor results for the generation fleet.
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.