As heat wave rolls in, California grid manager calls another Flex Alert, urges conservation

Another heat wave, another warning from the operators of California’s electricity grid.

The California Independent System Operator issued a Flex Alert for Friday afternoon and evening as temperatures are expected to zoom past 100 degrees and put renewed pressure on the state’s power network.

The alert is a voluntary call for conservation from 4 to 9 p.m., when the grid would be most vulnerable to rolling blackouts. Grid operators urge Californians to cool down their homes and businesses earlier in the day, but shut off major appliances and turn thermostats to 78 or higher once the alert takes effect.

This is the third major heat wave already this year, and each has been accompanied by the grid’s Flex Alerts. In early July the System Operator appealed to power generators and traders to make more supplies available to California for the balance of the summer and early fall.

While grid managers said in May they were fairly sure the state could avoid blackouts this year, their confidence has waned as successive heat waves smother the state — and the drought has wiped out an estimated 1,000 megawatts worth of power at the state’s hydro plants.

Last summer California endured two consecutive nights of rolling blackouts during a 110-degree heat wave through much of the West. The grid is considered most vulnerable after the sun goes down, solar generation fades, but it remains hot.

This story was originally published July 8, 2021 at 7:05 PM with the headline "As heat wave rolls in, California grid manager calls another Flex Alert, urges conservation."