Blackout risk rises as heat wave stresses largest US electric grids

• DOE authorized PJM to activate backup generation as a last resort before declaring a level 3 energy emergency alert, which precedes rotating blackouts
• MISO grid operator predicted Wednesday peak demand would reach about 121 gigawatts, approaching its all-time record of 127.1 GW
• Rural Missouri electric customers were asked to reduce consumption by unplugging unused devices and raising thermostats to ease strain on the grid

Summary: Blackout Risk Rises as Heat Wave Stresses Largest US Electric Grids

Key Development:

The U.S. faces escalating blackout risks across the Midwest and Mid-Atlantic regions as extreme heat threatens electricity supply capacity for millions of customers on Wednesday, September 2.

Critical Actions:

DOE Secretary Chris Wright authorized PJM Interconnection—the largest U.S. electric grid serving 67 million people from Washington D.C. to Chicago—to activate backup generation resources as a last resort before declaring a level 3 energy emergency alert, which precedes rotating blackouts. PJM issued a "maximum generation emergency" alert directing generators on planned outages to report how quickly they could restore service.

Grid Operators Affected:

• PJM Interconnection: Serves 67 million people across Mid-Atlantic to Midwest
• MISO (Midcontinent Independent System Operator): Covers 15 states; expects peak demand Wednesday to reach approximately 121 gigawatts, approaching its all-time record of 127.1 GW

Weather Conditions:

Temperatures in major cities including Chicago, St. Louis, and Washington D.C. expected to exceed 90°F (32°C) during peak electricity demand periods.

Consumer Impact:

In rural Missouri's Ozark region, Howell-Oregon Electric Cooperative requested customers reduce consumption by unplugging unused devices and raising thermostat settings to decrease air conditioning load.

Market Implications:

The situation highlights ongoing stress on U.S. electricity infrastructure during extreme weather events, raising concerns about grid reliability and the adequacy of generation capacity. MISO increased its normal reserve requirements as a buffer against unexpected outages and transmission congestion, signaling tight supply conditions that could impact energy prices and reliability across multiple states.