California power grid facing overwhelming demands on Tuesday; Rolling blackouts likely amid record heat

SAN FRANCISCO — California is facing its highest chance of blackouts this year as a brutal heat wave continues to blanket the state with triple-digit temperatures. 

State energy officials said the electrical load Tuesday afternoon could top 51,000 megawatts, the highest demand the state has ever seen.

As people crank up their air conditioners, the state forecasted record levels of energy use, said Elliot Mainzer, president of California Independent System Operators, which runs the state’s electrical grid. The state has additional energy capacity at the moment “but blackouts, rolling, rotating outages are a possibility,” Mainzer said, calling additional conservation “absolutely essential.”

The CAISO site Tuesday morning showed California could fall more than 5,000 megawatts short of its power supply at peak demand, forecasted for 5:30 pm.

California’s energy grid runs on a mix of mostly solar and natural gas during the day, along with some imports of power from other states. But solar power begins to fall off during the late afternoon and into the evening, which is the hottest time of day in some parts of the state. And some of the aging natural gas plants California relies on for backup power aren’t as reliable in hot weather.

At CAISO’s request on Monday, four temporary emergency power generators deployed by the Department of Water Resources in Roseville and Yuba City were activated for the first time since they were installed last year, providing up to 120 megawatts, enough electricity for 120,000 homes.

CAISO also has issued a Flex Alert call for voluntary conservation between 4 p.m. to 10 p.m. Tuesday, making seven alerts in as many days. Consumers were urged to keep air conditioners at 78 degrees (25.5 degrees C) or higher during the period and avoiding using major appliances such as ovens and dishwashers.

The efforts have worked to keep the lights on “but we have now entered the most intense phase of this heat wave” that could last into the week, and two to three times the level of conservation will be needed from people and businesses, Mainzer said.

CAISO also issued a Stage 2 Energy Emergency Alert from 6:30 p.m. to 8 p.m. Monday. The second of three emergency alert stages means taking emergency energy-saving measures “such as tapping backup generators, buying more power from other states and using so-called demand response programs,” according to a CAISO website. Stage 3 would be rolling blackouts.

Several hundred thousand Californians lost power in rolling blackouts in August 2020 amid hot weather, but the state avoided a similar scenario last summer. Gov. Gavin Newsom signed legislation on Friday that could allow the state’s last remaining nuclear plant to stay open beyond its planned 2025 closure, to ensure more power.

The National Weather Service predicted highs between 100 and 115 degrees (37.7 C and 46.1 C) across inland California, with 80s to 90s (above 26.6 C and below 37.2 C) closer to the coast. Nighttime won’t bring much relief, with many places seeing lows in the 80s or even 90s (above 26.6 C and below 37.2 C).