A widespread heatwave is placing significant strain on the United States’ largest electric grids, raising the risk of power outages across a wide region extending from the Midwest to the Mid-Atlantic. The US Department of Energy has issued warnings as demand for electricity escalates amid soaring temperatures.
The PJM Interconnection, the nation’s largest grid operator serving approximately 67 million people across an area from Washington, D.C., to Chicago, is among those most affected. On Tuesday night, Energy Secretary Chris Wright authorized PJM to activate backup generation resources as a precautionary measure ahead of a potential level three energy emergency alert. Such an alert is a critical step that may precede the implementation of rotating blackouts if conditions worsen.
The department characterized this action as part of efforts “to stabilize the Mid-Atlantic grid and mitigate the risk of blackouts.” Secretary Wright emphasized the priority of maintaining affordable and reliable power through periods of extreme heat.
Forecasts anticipated temperatures exceeding 90 degrees Fahrenheit (32 degrees Celsius) in key metropolitan areas including Chicago, St. Louis, and Washington, D.C., coinciding with peak electricity consumption times. Early Wednesday, PJM issued a “maximum generation emergency” alert, ordering generators that were already scheduled for outages to report their capacity for expedited return to service.
In parallel, the Midcontinent Independent System Operator (MISO), responsible for managing power in 15 states across the Midwest and South, projected peak electricity demand near record levels, estimating about 121 gigawatts on Wednesday. MISO’s historical peak demand is 127.1 gigawatts. The operator issued a warning about tight supply conditions and raised reserve margins to provide a buffer against unexpected outages or transmission constraints.
In response to the ongoing heat, local utilities took steps to encourage demand reduction. In the rural Ozark region of Missouri, the Howell-Oregon Electric Cooperative urged customers to unplug unused appliances and chargers and suggested raising thermostat settings to reduce air conditioning load.
The combination of extreme heat and high electricity demand has created challenging conditions for grid operators aiming to balance supply and avoid widespread disruptions. Authorities continue to monitor conditions closely and maintain readiness to implement emergency measures if necessary.