4 straight days: California’s grid manager issues a Flex Alert for Saturday

The operator that manages 80 percent of California’s electric grid has issued another Flex Alert, as a heat wave that has blanketed most of the state intensifies going into the start of the Labor Day weekend.

Concerned that surges in energy demand — primarily from homeowners and businesses turning up their air conditioning units — may push the power system to the brink, the California Independent System Operator on Friday extended its call for consumers to voluntarily reduce energy consumption between the hours of 4 and 9 p.m. through Saturday.

Combined with Flex Alerts already issued earlier this week and Friday, the latest round means energy conservation measures have been extended to run for at least four consecutive days.

“The major concern now is even higher temperatures forecast for Sunday, Monday and Tuesday,” the California ISO said in a statement, “with projected loads (on the state’s energy grid) climbing to more than 49,000 megawatts on Tuesday.”

That’s more than Thursday’s peak of 47,357 megawatts, which represented the highest level seen on the state’s grid since September 2017. The all-time record is 50,270 megawatts, set on July 24, 2006.

Cal ISO president Elliot Mainzer thanked utility customers for doing their part in helping avoid statewide rotating outages, estimating that homeowners and businesses, as well as other conservation measures, reduced about 1,200 megawatts of load off of the power system on Thursday.

But Mainzer said, in an online message, “the hottest weather in this extended heat wave is still ahead of us. Much of California will see record triple-digit temperatures, with only moderate cooling at night, right through the Labor Day holiday weekend and into the middle of next week so electricity conservation is going to be essential in keeping the power flowing in California without interruption.”

Grid officials say they’re keeping an eye on a wildfire in San Diego’s East County and another north of Los Angeles near Castaic that may threaten power lines or electricity generation from nearby power plants. The fire in East County, dubbed the Border 32 Fire, has burned about about 4,400 acres near the backcountry town of Potrero, with flames moving south near the U.S.-Mexico border.

Between 4 p.m. and 9 p.m., the ISO recommends utility customers:

• set thermostat to 78 degrees or higher, if health permits
• avoid charging electric vehicles
• avoid using major appliances, and
• turn off all unnecessary lights

The grid manager is trying to avoid a repeat of what happened on Aug. 14 and 15 of 2020 when parts of the state lost power for up to 2 1/2 hours. That marked the first time since the California energy crisis of 2000 and 2001 the ISO issued a Stage 3 Emergency to restore reserve margins to ensure the safe running of the state’s grid.

Union-Tribune staff writer Emily Alvarenga contributed to this story.