A multi-state heatwave will test California’s electric grid over Labor Day weekend as triple-digit temperatures hit millions of people simultaneously, prompting concern that the state could once again turn to rolling blackouts.

State officials hope to avoid that situation by asking residents to voluntarily use less power, even as the heat tempts Californians to crank up their air conditioners. Gov. Gavin Newsom also said the state has made infrastructure improvements since its last round of heat-fueled blackouts in 2020.

But if millions of people don’t conserve electricity, officials could be forced to temporarily cut the power in some regions for short periods of time.

The latest:

  • California officials say it will be tough to meet the unusually high demand for electricity during the heatwave.
  • The state’s calls for voluntary electricity conservation often work for a short time, but people struggle to cut back during longer heat events, according to Daniel Kammen, an energy professor at the University of California, Berkeley.
  • Rolling blackouts don’t appear imminent — yet. 

What is a Flex Alert?

With excessive heat forecast into the weekend throughout California, the state issued a statewide Flex Alert Wednesday — a call for voluntary electricity conservation.

California’s Independent System Operator, which oversees the state’s electric power grid, has urged residents to conserve power between 4 p.m. and 9 p.m, when the grid is most stressed from high demand and less solar energy.

The system operator recommended Californians set their thermostats to 78 degrees or higher, avoid using major appliances or charging electric vehicles, and turn off unnecessary lights.

The alerts are typically effective, sometimes leading to more than a 10% reduction in overall energy use, according to Daniel Kammen, an energy professor at the University of California, Berkeley.

“We typically see a pretty good response,” Kammen told USA TODAY. 

California has also added an estimated extra 4,000 megawatts to the grid since July 2020 as part of its goal to accelerate its transition to clean energy.