Flex Alert issued by California power grid manager as heat wave strains electricity supply

With a potentially devastating heat wave rolling through California, the managers of the state’s power grid issued a Flex Alert for Thursday, a call for voluntary conservation across the state.

Mindful of the two nights of rolling blackouts that clobbered California last August, the California Independent System Operator issued the Flex Alert more than 24 hours before the alert actually takes effect — at 5 p.m. Thursday. The alert runs until 10 p.m.

The grid operator has said supplies will be tight this week, especially Thursday, when it forecast that supplies could fall short of demand. But the organization hasn’t predicted actual blackouts yet and the likelihood of outages Thursday “is relatively low,” said Eliot Mainzer, the ISO’s chief executive.

But he warned that “conditions can change” and he urged consumers to heed the Flex Alert.

“Californians have stepped up many times before when asked to pitch in and I’m confident they will do so,” Mainzer told reporters Wednesday.

“We have not gone into emergency conditions. At this point there’s still some uncertainty” about how much strain the grid will face Thursday, he said.

Among other things, he called on Californians to set their thermostats to 78 degrees or higher and turn off major appliances and lights.

Evenings remain the grid’s most delicate hours, when solar power diminishes but the heat doesn’t. “We need everybody to bear down,” Mainzer said.

At the same time, officials said the situation doesn’t seem to be as dire as it appeared just two days ago, when they predicted a potential shortfall of more than 3,300 megawatts — enough to power 2.6 million homes. Now, the shortfall is expected to be around 300 megawatts, a deficit that is likely to be covered by the volume of conservation typically generated by a Flex Alert, said Mark Rothleder, the grid manager’s chief operating officer.

Although temperatures could hit 110 degrees in the Sacramento area and Central Valley, Rothleder said the heat wave isn’t as bad as the one in August, when the blackouts occurred. This time around, temperatures are much cooler on the coast, and “that may make the difference,” he said.

Another factor working in California’s favor this week: The grid manager has been able to procure additional supplies in the past 24 hours, including some electricity from out-of-state sources, Rothleder said. Those out-of-state supplies were much harder to find last August.

If more conservation is needed this week, other measures can be taken beyond voluntary Flex Alerts. For instance, the big utilities such as PG&E Corp. have “interruptible customers” who’ve agreed to be taken offline during crunch periods, in return for discounted rates.

Mainzer said the state is better prepared than last year; among other things, the state has added about 2,000 megawatts worth of battery storage, which could prove critical in the evening hours when solar power dissipates.

On the other hand, the severe drought is reducing the availability of hydro power. “It’s definitely moving in the wrong direction,” Mainzer said.

The Sacramento Municipal Utility District isn’t part of the state’s grid and says it doesn’t believe it faces a blackout threat this week.

This story was originally published June 16, 2021 at 4:52 PM.