Residents urged to conserve power again as California extends Flex Alert to Friday

California residents were asked to voluntarily conserve power again Friday as a heat wave baking the U.S. West strained the state’s energy grid and raised the possibility of rotating outages.

As temperatures spiked on Thursday, Gov. Gavin Newsom signed an emergency proclamation that suspended certain permitting requirements, allowing power plants to ramp up operations if necessary to meet the demand for electricity. The proclamation cited the “extreme heat peril” facing the state this week.

The California Independent System Operator, which runs the energy grid, issued a Flex Alert for 6 to 9 p.m. Friday. During those hours, people are urged to set their thermostats to 78 degrees or higher and avoid using washers, dishwashers and other major appliances. An alert was also in place Thursday evening.

Pacific Gas & Electric said rotating power outages were possible Thursday night in parts of Yuba and Placer counties in Northern California.

During an intense Western heat wave last August, the state saw two days of rotating outages that affected more than 200,000 people. They were the first such blackouts since 2001.

Power officials said the electrical grid has seen upgrades in power storage and transmission since then, including adding about 3,500 megawatts of capacity — enough to power some 2.6 million homes. That includes 2,000 megawatts worth of battery storage that could be crucial when solar power generation tails off after dark.

Temperatures in the 80s and 90s were recorded up and down the state, with triple-digit highs in deserts, some mountains, non-coastal valley and interior areas.

In Southern California, Palm Springs tied the all-time record of 123 degrees (50.5 Celsius), reached only three other times, in 1993 and twice in 1995.

The National Weather Service warned of “dangerously hot, potentially life-threatening temperatures” through Saturday in the San Joaquin Valley.

A heat advisory was issued through Friday night for much of the San Francisco Bay Area, and several counties announced they were opening cooling centers.

Temperatures were expected to ease only slightly heading into Sunday, the official first day of summer.

The heat was due to a dome of high pressure that has covered the U.S. West. Oppressive daytime highs have been followed by very warm nights. Death Valley roasted at 125 degrees (52 degrees Celsius) at midweek.

The heat wave comes amid a drought that has dried up vegetation, increasing fire danger. There have been a number of small wildfires around California this week but the state avoided the kind of fierce gusts that drove last year’s devastating blazes.