- If conditions worsen, utilities will determine how to rotate the outages.
- The extreme heat that broiled the drought-ravaged state over the Labor Day weekend will continue for much of the week.
- The vast area of high pressure sitting over the interior West is likely to weaken late this week.
Record-breaking temperatures were forecast to drive historic power demands in California on Tuesday, straining the electrical grid and making rotating outages increasingly likely, authorities said.
Over 500,000 customers in California were given advanced notice to prepare for potential rotating outages, often called rolling blackouts, by Tuesday afternoon, Pacific Gas and Electric said. Hours later, California's electric grid operator issued Level 3 energy emergency alerts across the state, with imminent rolling blackouts "very possible," the grid operator said.
Elliot Mainzer, CEO of the California Independent System Operator, said the "extraordinary heat event we are experiencing" makes it essential that homes and businesses reduce energy use after 4 p.m. That means not using major appliances and setting thermostats at 78 degrees or higher.
By 7 p.m. Tuesday, California's grid reached peak demand at over 52,000 megawatts, hitting a new all-time record for the state. The state's maximum capacity is 56,000 megawatts. Despite the troubling numbers, California's grid operator noted on Twitter that "conservation is making a difference."
The system declared an emergency Monday from 5 to 9 p.m. A "Flex Alert" urging consumers to reduce their power use in the late afternoon and evening remained in effect Tuesday, marking seven consecutive days the call to cut demand has been issued.
“Over the last several days, we have seen a positive impact on lowering demand because of everyone’s help," Mainzer said. "But now we need a reduction in energy use that is two or three times greater than what we’ve seen so far.”
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How would rotating outages work?
California's grid operator issued a Level 3 energy emergency alert for residents in both Northern and Southern California on Tuesday, forecasting an energy deficiency across the grid and "imminent or in progress" blackouts.
Utilities will determine how to rotate the outages. The goal: keep them as short as possible. Mainzer said that for two days in August 2020, outages affecting about 800,000 homes and businesses lasted anywhere from 15 minutes to about 2½ hours – the first time outages were ordered in California because of insufficient supplies in nearly 20 years.
“We never want to get to that point, of course,” Mainzer said. “We want everyone to be prepared."
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How California gets its power
California’s energy grid involves mostly solar and natural gas during the day, along with some imports of power from other states. But solar power begins to fall off late in the day, the hottest time in some parts of the state. Some of the aging natural gas plants California relies on for backup power struggle in hot weather.
Gov. Gavin Newsom signed legislation last week allowing the Diablo Canyon Power Plant, the state’s last nuclear plant, to stay open an additional five years beyond its planned 2025 closure.
Weather fueling wildfires
Wildfire danger was extreme as the blazing hot, dry weather turned brush to tinder. Four deaths were reported over the Labor Day weekend as more than 4,000 firefighters battled fires across the state, – 45 new blazes on Sunday alone, said Anale Burlew, a deputy chief with the California Department of Forestry and Fire Protection.
Wildfires could also affect power outages, said Daniel Kammen, an energy professor at the University of California, Berkeley.
"But one of the big unknowns in this is that we also expect wildfires. And wildfires will cause us to have to shut down certain transmission lines, de-energizing them to prevent wildfires," he told USA TODAY.
Fires threatening areas with power lines above ground could cause "rolling brownouts," Kammen said, where outages are scheduled in advance to prevent fires from spreading further.
EVEN MORE EXTREME': Blistering heat to roast California, other Western states this week
California cities break temperature records
More than 100 records for daily high temperatures could be broken between Sunday and Wednesday, the National Weather Service said.
California's capital recorded 117 degrees at Sacramento International Airport on Monday, breaking the all-time high temperature of 115 degrees Fahrenheit, which was set in 1961.
Sacramento, which had not climbed above 109 degrees in any previous September, is expected to top 110 all but one day through Saturday. Fresno in the Central Valley figures to surge past its September record of 111.
The nation’s hottest spot, Death Valley, California, was forecast to hit 125 degrees Tuesday, continuing an unprecedented run of blistering heat and inching toward breaking the highest September temperature ever recorded on Earth. The record is 126 degrees.
Forecasters cautioned that Death Valley's famous Furnace Creek thermometer could produce even higher readings.
“That's not the official thermometer – so that would actually not be used to set the records,” said Brian Planz, a meteorologist with the National Weather Service in Las Vegas.
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When will a reprieve come?
AccuWeather reports that the vast area of high pressure sitting over the interior West is likely to weaken late this week. That could allow cooler air to slide down from Canada, through the Northwestern states and into the Rockies.
The cooling effect in Southern California, southern Nevada and Arizona will be aided by increasing cloud cover associated, in part, with Hurricane Kay at sea now off the coast of Mexico, AccuWeather Senior Meteorologist Brett Anderson said.
Contributing: Jorge L. Ortiz
