With scorching temperatures expected to peak Tuesday from an ongoing heat wave, California is poised to hit a new record for electricity demand as air conditioners huff and chug in homes and offices across the sweltering valleys. .
And with that record demand comes a question Californians are becoming all too familiar with: Will there be enough power, or will the lights go out to protect the electric grid from systematic collapse?
“We are consuming away more electricity than we have before,” said Severin Borenstein, professor of business administration and public policy and faculty director of the Energy Institute at the University of California-Berkeley’s Haas School of Business. “It’s quite possible we will get in a situation where we will have to impose rotating outages, which you have to do to prevent a whole system crash.”
If electricity supplies can’t meet demand, utilities including Pacific Gas & Electric, would have to rotate outages to blocks of customers for an hour or so to lighten the load. The state last saw such rolling blackouts over two days in August 2020, affecting about 800,000 homes and businesses and lasting anywhere from 15 minutes to about two and a half hours.
Before that, the last rolling blackouts were during the state’s electricity crisis of 2000 and 2001 caused in part by a botched deregulation scheme, which factored into the 2003 recall of Gov. Gray Davis.
The California Independent System Operator, the agency that manages the state’s electric power grid, said peak electricity demand Tuesday is expected to reach 51,145 megawatts, which would set a new record from the previous high of 50,270 megawatts in 2006. A megawatt — 1,000 kilowatts — is roughly enough electricity for the instantaneous demand of 750 homes at once.
The ISO was projecting supply deficiencies of 400 to 3,400 MW between the hours of 5 p.m. and 9 p.m. Tuesday, and pleading with residents and businesses to continue to reduce power use in the afternoon.
“Record-breaking temperatures are leading to historic high forecasted demands for power,” the ISO said, putting even greater strain on the grid and “significantly increasing the likelihood of rotating outages unless consumers can reduce their energy use even more than they have so far.”
The ISO said Tuesday that “no rotating outages are anticipated at this time,” but issued its seventh straight “Flex Alert,” calling for electricity consumers to reduce their use in the afternoon by setting their air conditioning thermostat to 78 degrees or higher, avoid using major appliances such as washers and dryers and charging electric vehicles, and turning off lights when not in use.
Those conservation efforts, the ISO said, have paid off so far, lowering demand by about 1,000 megawatts Monday afternoon.
“Consumer and commercial demand response, including Flex Alerts, has been helping to extend sparse supplies at critical hours so far this week, giving operators extra cushion in supplies,” the ISO said Tuesday.
Borenstein noted that rolling blackouts aren’t the same as the Public Safety Power Shutoffs put in place to avoid power lines sparking wildfires during high winds. Those outages can last for days as utility crews must inspect lines across wide areas for damage before re-energizing them.
Though the state avoided rotating outages on the Labor Day holiday, it wasn’t far from requiring them.
“It was close,” Borenstein said. “It definitely was not assured.”
Even without rotating outages, heat can damage electrical equipment and cause localized outages. PG&E on Tuesday reported about 5,200 customers without power due to electrical equipment failure.
But the threat of outages can increase as the heat wave wears on, Borenstein said, as buildings don’t have enough time to cool off overnight before temperatures rise again the next day.
What makes ensuring power supply tricky for utilities and grid operators is that it’s unclear how much the principal source of power demand during heat waves — air conditioning — is increasing. Many homes and businesses near the coast that traditionally didn’t have air conditioning have been installing cooling systems, but it’s not being tracked.
“You find out on the hottest day of the year just how bad it’s going to be,” Borenstein said. “The forecasters do their best, based on previous relatively hot days, but we don’t know until we get to the day.”
Check back for more on this developing story.