Extreme heat wave testing California’s power grid; officials issue Flex Alert, warn of potential blackouts

The worst heat wave of the year is already threatening California’s power grid, which could be pushed to its peak as large swaths of the state face scorching temperatures for as long as a week — with little respite.

Officials are urging Californians to limit electricity use when possible to minimize strain on the state’s energy providers, warning otherwise of potential rolling blackouts. Losing power during such extreme heat can be extremely dangerous, if not deadly, especially for the most vulnerable.

California officials on Wednesday issued the first statewide Flex Alert during this heat wave, as most of the state entered its first day of extreme heat in this wave, from the upper 90s to 110s.

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The heat wave — a result of a large dome of hot air sitting over Central and Southern California — was expected last through at least Tuesday next week for much of the state.

“We’re not super confident on when it’s going to end,” said Bill Rasch, National Weather Service, clarifying that the blistering temperatures could continue into next Wednesday. Forecasters expect the next few days will become California’s longest and most intense heat wave of the year.

Governor Gavin Newsom declared a state of emergency Wednesday following a request from the California Independent System Operator, which operates the state’s power grid, intended to help increase energy production during the intense period of extreme heat. Cal ISO officials said the Flex Alert was issued after determining that the energy supply and demand was tighter than anticipated, primarily from air conditioning use.

Flex alerts are likely to be part of the response over the coming days, but have not yet been announced for later in the week.

Despite efforts to bring more capacity online, the system remains vulnerable during extreme weather events like heat waves, in part because neighboring areas from where California imports energy are also experiencing crushingly hot temperatures. Droughts are also affecting the energy grid by limiting hydropower supply sources, officials said.

“We are anticipating this extreme heat to be a length and duration the likes of which we haven’t experienced in some time,” Newsom said. Record-breaking heat is possible Wednesday, Thursday, Sunday and Monday, according to the National Weather Service.

Newsom advised Californians to turn their thermostats up to 78 degrees during the Flex Alert from 4 to 9 p.m. Wednesday. The governor warned that Sunday and Monday will be the most challenging days for the energy grid.

TK TK the Vice Chair for the Energy Commission said the state has been working to bring more supplies online, including through more government projects coming online and increasing and the grid’s storage capacity.

The high temperatures hit as the governor and his team pressure lawmakers to pass a bill on the final day of the legislative year to keep the Diablo Canyon nuclear plant open until 2030.

The plant, which sits on the coast of San Luis Obispo County and generated 6% of the electricity in the state last year, is slated to close in 2025.

Newsom argues Diablo must stay open for California to keep the lights on during heat waves and avoid a repeat of the rolling blackouts the state experienced two years ago. Environmental groups that pushed six years ago for the closure of Diablo strongly oppose.

Temperatures along the coasts could range from 80 to 95 degrees Wednesday through Saturday, before increasing to 100 degrees Sunday and Monday, the weather service said.

The valleys and mountains could be pummeled by 95- to 110-degree temperatures Wednesday through Saturday, and highs of up to 115 Sunday and Monday, meteorologists said.

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From Wednesday through Labor Day weekend, weather forecasters predict temperatures could reach as high as 115 degrees in some parts of Southern California.

During a Flex Alert, consumers are urged to reduce their energy use in the afternoon and evening hours, when the grid is most stressed because of high demand and less available energy from solar panels.

Customers are asked to avoid using large appliances and charging electric vehicles, and turn off unnecessary lights.

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Experts remind Southern California residents to stay hydrated, stay out of the direct sun and shelter in air conditioned buildings, if possible.

Cal ISO said it is taking steps “to bring all available resources online,” including issuing orders for restricted maintenance operations from Wednesday through Tuesday, noon to 10 p.m. each day.

Wildfires, power outages and other threats are also a major concern, said MG from Governor’s Office of Emergency Services (Cal OES).