Article content

(Bloomberg) — California officials warned that the worst of a prolonged heat wave will stress the state’s power grid through the long Labor Day weekend, increasing the risk of blackouts amid forecasts of record-breaking temperatures.

Article content

The state’s grid operator is urging residents to cut back on energy use during the hottest parts of the day, when thermostats in some parts of the Central Valley are forecast to hit highs of 115 degrees Fahrenheit (46 degrees Celsius) into the middle of next week. The searing heat will push electricity demand to the highest levels in years. Demand on Thursday hit a peak of 47,357 megawatts, the highest since September 2017, grid officials said.

Article content

The California Independent System Operator on Saturday issued another grid emergency watch, saying that energy shortages are expected between 5 p.m. to 8 p.m. on Sunday.  The grid operator, which had already called for homes and businesses to reduce power Saturday afternoon and early evening, urged residents to continue to conserve electricity during the same times on Sunday.  

Article content

“These last few days are likely to be a dress rehearsal for what’s going to be much more significantly stressed set of conditions as we get into the heart of the weekend,” Caiso Chief Executive Officer Elliot Mainzer said at a briefing Saturday morning before the latest conservation notice was issued. “We really appreciate the efforts of consumers so far, we’re going to be asking for more, it’s going to be a sustained effort.”   

The threat of outages underscores the power grid’s increasing vulnerability as climate change disrupts weather patterns amid the push to transition from fossil fuels to renewable energy. California is enduring its worst drought in 1,200 years, sapping hydropower production.

At the same time, older gas-burning plants have been closing faster than solar, wind and battery facilities can replace them. Earlier this week, California lawmakers nearly unanimously approved a bill to extend the life of the state’s only remaining nuclear power plant by five years as a protection against blackouts.

Article content

The extreme heat already has taken down a number of power generators this week, Caiso said in a statement Friday. Grid operators said they are also concerned about two major wildfires threatening transmission lines and power plants near Los Angeles and San Diego. On Saturday, Mainzer said Caiso was monitoring the latest fire conditions, including a new wildfire outside Weed in Northern California that began Friday. 

“We’ll be keeping a close eye on these fire conditions,” Mainzer said. “They do have the potential to impact the bulk electrical system, and we’re going to be doing everything we can to make sure that the generation fleet in California is as strong as possible.”

(Updates with grid operator issuing emergency watch for Sunday in third paragraph.)