Blackout risk rises as heat wave stresses largest US electric grids

As a heat wave intensifies across the United States, the risk of power outages is expected to intensify on Wednesday, according to reports. The US Department of Energy (DOE) warned of potential blackout risks, specifically within the PJM Interconnection, a massive grid serving 67 million people from Washington DC to Chicago. The DOE instructed PJM to activate backup generators as a last resort before declaring a level 3 energy emergency alert, which could precede rotating blackouts.

Late on Tuesday, DOE Secretary Chris Wright authorized PJM to deploy backup power resources. This precautionary measure aims to stabilize the Mid-Atlantic grid and reduce the risk of widespread blackouts. Wright emphasized the importance of maintaining reliable and secure power for American families and businesses during periods of extreme heat.

On Wednesday, temperatures in Chicago, St. Louis, and Washington DC were forecast to surpass 90 degrees Fahrenheit (32 degrees Celsius) during peak electricity demand. The PJM Interconnection's "maximum generation emergency" alert was issued early on Wednesday, prompting generators to report the speed at which they could restore units to service.

Meanwhile, the Midcontinent Independent System Operator (MISO), which oversees 15 US states in the Midwest and South, expects peak demand on Wednesday to approach record levels, around 121 gigawatts. MISO's previous all-time high is 127.1 gigawatts. To counteract potential power plant outages and transmission line congestion, MISO increased its reserve requirement.

In rural Missouri's Ozark region, the Howell-Oregon Electric Cooperative advised customers to unplug unused chargers and appliances due to the extreme heat. Customers were also encouraged to raise their thermostats to minimize air conditioning use.