California issue flex alert amid 'excessive heat'

California residents are urged to cut their electricity use as soaring temperatures led power regulators to issue a flex alert.

The alert was extended statewide from 4-9 p.m. Sept. 1, California ISO, the state grid regulator, announced.

During a flex alert, consumers are asked to avoid using major appliances, recharging electric vehicles and other uses that can stress the power grid. Another way to conserve energy is to set thermostats to 78 degrees or warmer. 

"With excessive heat in the forecast across much of the state and Western U.S., the grid operator is expecting high electricity demand, primarily from air conditioning use, and is calling for voluntary conservation steps to help balance supply and demand," Cal ISO said.

More flex alerts could be issued in the coming days as the excessive heat, which could push temperatures up to 110 degrees in parts of the Bay Area, is forecast to last through Labor Day. 

The National Weather Service issued an excessive heat warning from Saturday morning to Tuesday night for many parts of the Bay Area, including San Jose, the North Bay valleys and Santa Cruz mountains. See more about the warning here.

The weather has raised concerns among Bay Area fire departments that fires could spread quickly in the coming days.

Demand for power often increases when temperatures are high as more people turn on air-conditioning.