Reduce your electricity use during California heat wave this week, state asks

The California Independent System Operator (ISO) has issued a statewide Flex Alert asking Californians to voluntarily conserve electricity from 5 p.m to 9 p.m Tuesday and Wednesday.

The alert comes as temperatures are projected to reach high levels in the upcoming days. That means more electricity spent on things like air-conditioning, resulting in an added strain on the electricity grid.

“We’re going to see some of the highest demand on the system that we’ve seen,” said Steven Greenlee, a senior public information officer at California ISO.

ISO projects that Californians will consume 48,000 to 49,000 megawatts of electricity on both Tuesday and Wednesday. Usually, summer electricity use ranges in the low to mid-40,000-megawatt range. For perspective, 500 megawatts of electricity can power half a million homes.

Since temperatures — and, consequently, electricity usage — have been rising across the entire West Coast, California ISO will not be able to rely on importing electricity from places like the Pacific Northwest to offset the extra power being used in-state.

To conserve energy in the days ahead, ISO is encouraging Californians to turn off unused lights, refrain from using large appliances like washing machines and dishwashers between 5 p.m and 9 p.m (peak hours), close window blinds and turn up the thermostat to at least 78 degrees, if possible.

“We don’t want anybody doing anything that would threaten their health or safety,” Greenlee said. “This is a voluntary call for conservation. It’s our first tool in our toolbox to manage supply and demand.”

ISO has found that calling Flex Alerts in years past has reduced electricity usage in peak hours by up to 500 megawatts. But if ISO is still unable to handle increased electricity use, further emergency measures may have to be taken, including rotating power outages. According to Greenlee, there’s no way to know for sure if those measures will be necessary.

“The thing about the (electricity) grid is that conditions can change very quickly,” he said.

For more tips on how to conserve energy during Flex Alerts and to receive future Flex Alerts, go to To receive immediate emergency notifications about California’s power supply, you can download California ISO’s app, ISO today, on both iOS and Android.