Scorching Heat Has US Power Grids Bracing for Blackouts

Power grids serving more than 70 million customers are warning of possible blackouts as a blistering heat wave bears down on the central US.

(Bloomberg) — Power grids serving more than 70 million customers are warning of possible blackouts as a blistering heat wave bears down on the central US. 

Temperatures in Iowa will reach 100F (38C) and parts of Texas will hit a searing 107F, with heat alerts stretching across 20 states from Minnesota to Louisiana, according to the National Weather Service. When considering the humidity, temperatures may feel close to 120F.

Electricity supplies will be tight Thursday evening as millions of people crank up air conditioners. Texas has a “high potential” to declare an energy emergency Thursday evening, and the grid operator in the Midwest has already done so, indicating the regions may have to resort to rolling blackouts if surging demand overwhelms power generation. The vast expanse of the heat will limit the ability to import power from other grids, potentially exacerbating any shortages.

“It’s basically every grid for themselves at that point,” said Joshua Rhodes, an energy research scientist at the University of Texas at Austin.

This week’s heat wave is smashing records dating back more than a century, taxing energy grids and raising health risks in a region with a population of about 145 million. It’s the latest in a string of climate disasters, from deadly wildfires to hurricanes, that have pummeled the US in recent weeks. 

Read more: Searing Heat Is Shattering Century-Old Records Across Central US

For Texas, this is the most serious threat to the grid thus far this summer. The Electric Reliability Council of Texas anticipates power supplies falling short of demand from about 7 p.m. to 9:30 p.m. local time, according to forecasts compiled by Nrgstream, a data provider. Grid operator Ercot serves 26 million customers in the state and is calling on the public to voluntarily reduce power consumption.

Still, the constraints are likely to mean 15-minute rolling outages in residential neighborhoods, in contrast to the crippling blackouts that gripped Texas in 2021 during deadly Winter Storm Uri. 

In the Midwest, “the record-breaking heat wave is driving electricity demand to near all-time highs,” Brandon Morris, a spokesman for MISO, the Midcontinent Independent System Operator, said in an email. 

The Midwest grid operator issued a maximum generation emergency event notice through 10 p.m. local time, indicating that it may be close to imposing rolling blackouts. MISO serves 45 million customers in 15 states from North Dakota to Mississippi, as well as Canada’s Manitoba province. 

MISO “may already be at the brink,” Rhodes said. 

–With assistance from Brian K. Sullivan, Mark Chediak and Rachel Adams-Heard.

(Updates with details from Texas in third paragraph.)

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