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Cal ISO calls for another Flex Alert Friday due to searing weather conditions

As a heat wave continues to grip Southern California and drive up air-conditioner use, a Flex Alert calling for voluntary power conservation to reduce strain on the state's electric grid will be in effect for a third straight day Friday.

But do flex alerts actually make a difference? Scott Anders, director of the Energy Policy Initiatives Center at the University of San Diego told KPBS they do.

“It can make a difference because really if you think about it, it just takes a little bit to push us over the edge. And so this kind of voluntary call can actually create a buffer to help grid operators keep things going,” Anders said.


Resources to beat the heat

  • Click here for a list of Cool Zones in San Diego County or call 211 for information on the nearest near you.
  • People unable to get to a Cool Zone location without transportation assistance can call 211 to be connected to a transportation or rideshare service at no cost.
  • Seniors, people with disabilities or those on limited incomes can request a free electric fan from the county at no cost. Call 211 or fill out this survey to see if you're eligible.

Anders said the flex alerts coincide with the time of day when much of the grid’s solar energy reserves start to deplete.

“We're asking a lot of the grid. We want to have more renewable electricity – we want to charge our cars from the grid, we want to use all electric appliances from the grid – when the grid really has never done that before,” Anders told KPBS.

The California Independent System Operator — which manages the state's power grid — issued the first Flex Alert of the week on Wednesday, urging residents to reduce electricity use from 4 to 9 p.m. The alert worked, and the state avoided any involuntary blackouts.

Another Flex Alert took effect at 4 p.m. Thursday, again continuing until 9 p.m. And with the forecast still calling for high heat, Cal-ISO issued yet another Flex Alert for Friday for the same hours.

Elliott Mainzer is the CEO of Cal-ISO.


“The prolonged heat wave across much of California and the West pushed demand to its highest levels for our grid since September 2017. Today we want everyone to know the hottest in this extended heat wave is still ahead of us,” he said Friday.

According to Cal-ISO, electrical demand on Thursday topped out at 47,357 megawatts. The agency projected that demand could exceed that number on Sunday, Monday and Tuesday, with Tuesday's forecast at 49,000 megawatts.

Flex Alert

During Flex Alerts, residents are urged to take power-saving steps such as:

— setting thermostats to 78 degrees or higher;
— avoiding use of major appliances;
— turning off unnecessary lights; and
— avoid charging electric vehicles.

Residents are also advised to pre-cool their homes as much as possible, and close blinds and drapes to keep interiors cool.

"The ISO is working with state agencies and market participants to bring all available energy resources online for what are expected to be the most challenging days of the heat wave," according to Cal-ISO.

Samantha Mohn is a San Diego resident who thinks too much responsibility for energy use is falling on everyday Californians.

“I think that it's a lot to ask of people to not use these appliances when this is the time when they're home,” she said. “After people get home from work or maybe kids get off of school people tend to turn on their ACs or watch TV and make dinner or make food. So these hours they're asking us to do it dont really work with people’s schedules a lot.”

Locally, SDG&E is not planning to impose temporary power outages in San Diego County due to the elevated risk of wildfires. The utility company said on its weather page that there are no Public Safety Power Shutoffs anticipated through Sept. 8.

However, SDG&E has activated an energy conservation demand response event for Saturday from 4-9 p.m. for customers enrolled in “event-based” pricing plans. That means customers could pay up to 400% more for their energy use during this time period. The company said “Depending on grid conditions, it is possible that these DR events … will be called again.”

Cal-ISO has warned that more Flex Alerts are likely to be posted during the duration of the heat wave, which is expected to linger until at least Tuesday, possibly longer in some areas.

A Flex Alert is the lowest-level notification issued by Cal-ISO, but if voluntary conservation fails to cut strain on the power grid, the agency could move into a series of emergency alerts that could ultimately lead to rolling blackouts.