State’s grid operator asks consumers to reduce energy usage for at least 2 days

San Diego County is under an excessive heat warning.
San Diego County is under an excessive heat warning.
(Gary Robbins / The San Diego Union-Tribune )

Request comes as heat wave forecast grows worse for San Diego County.


California’s primary power grid manager has issued appeals to utility customers to reduce their energy usage for at least two consecutive days to help the state cope with a heat wave that could be worse than originally anticipated.

The National Weather Service said Wednesday that temperatures are likely to be 100 to 105 degrees across much of inland San Diego County Saturday through Monday, and some spots could hit the 110- to 113-degree range. Forecasters say some of the worst heat will occur in areas like Escondido, Ramona, Valley Center, Lakeside and El Cajon.

It’s possible the temperature will hit 100 Saturday when San Diego State University plays its first football game at the recently completed Snapdragon Stadium in Mission Valley.

Just hours after the California Independent System Operator issued a Flex Alert that called on homeowners and businesses to voluntarily cut back from 4 p.m. to 9 p.m. on Wednesday, the grid manager extended the alert for the same time frame on Thursday.

And more calls to conserve energy may be coming.

“Additional Flex Alerts could be issued through the Labor Day weekend as triple-digit temperatures are forecast across much of California and the West,” the system operator, known as the California ISO for short, said.

The extensive heat wave will likely result in a surge in demand for electricity — primarily from air conditioners — by homeowners and businesses looking to cool off.

In a Flex Alert, the system operator asks energy users to voluntarily cut consumption when the state’s grid is under the most strain. The 4 p.m. to 9 p.m. period is particularly crucial because that coincides with solar energy production decreasing and eventually disappearing from the grid as the sun goes down.

Energy conservation measures include setting thermostats to 78 degrees or higher (if health permits), turning off unnecessary lights and avoiding the use of major appliances. And for the first time, the ISO this week has asked customers to avoid charging their electric vehicles while the Flex Alerts are in effect.

People are encouraged to pre-cool homes by closing binds and drapes. Residents should drink plenty of water and wear light, loose-fitting clothes. Children, elderly people and pet should not be left in a car unattended.

The ISO manages the electricity system for about 80 percent of the state.

“No one denies heat waves existed long before climate change, but the duration and intensity have never been more challenging,” Gov. Gavin Newsom said in a public address Wednesday encouraging people to do their part.

“We’ve headed these issues off in the past,” he added, “and I’m confident we’ll do it again this year and this week.”

Forecasters said that there’s a possibility that a coastal eddy will develop on Sunday afternoon and send some cool, moist air ashore.

In recent days, sea surface temperatures have dropped to the 65- to 71-degree level, which is significantly below average. But the eddy would largely benefit only the coast.

Forecast models predict that winds off the desert will blow west during the Labor Day weekend, carrying hot air to much of San Diego County.

The heat wave has already started. Through early Wednesday afternoon, the temperature had hit 102 at the Ramona Airport, 101 in Descanso and Santee, 99 at Gillespie Field in El Cajon, 96 in Escondido and other parts of El Cajon, and 95 in Lemon Grove.


5:25 p.m. Aug. 31, 2022: This story has been updated to show the California ISO extending the Flex Alert through Thursday, Sept. 1.

1:20 p.m. Aug. 31, 2022: This story has been updated with new weather forecasts.