At least eight utilities set all-time records for electricity demand

Climate change is increasing the number of extremely hot days, putting more strain on the power grid

Energy efficiency and cheaper batteries could help utilities cope with rising peak demand

As record temperatures scorched the Southwest last week, homes and businesses from California to Texas responded by cranking up their air conditioners — in some cases, using record amounts of electricity.

At least eight utilities across five states saw electricity demand reach all-time highs, meaning they provided more simultaneous power than they'd ever provided before. That unprecedented demand didn't substantially add to the risk of power outages, since utilities are required to keep plenty of backup power in reserve. But with communities across the U.S. already experiencing a rise in extremely hot days due to climate change, electricity use records are expected to become more common — and utilities may need to spend billions of dollars to prepare, or else risk power outages.

Maximilian Auffhammer, an environmental economist at the University of California, Berkeley, co-authored a first-of-its-kind paper earlier this year projecting widespread increases in peak electricity demand as temperatures keep going up. He said the biggest impacts will be felt in hot places with growing populations, including Arizona, California, Florida and Texas.

"Climate change makes these extreme heat days a lot more likely, and we're seeing some evidence of the frequency of these extreme heat days going up," he said.

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Last week's sizzling temperatures are a preview of things to come.

As Phoenix hit a record 119 degrees on Tuesday — it was so hot that some airplanes were unable to take off — Arizona's three largest utilities all shattered their records for most simultaneous electricity use. Salt River Project, which serves 1 million electric customers in the Phoenix area, actually set records twice — first on Monday, when demand hit 6,981 megawatts, then again on Tuesday, when customers used 7,219 megawatts. The utility's previous record, set last summer, was 6,873 megawatts.

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El Paso Electric Company, which serves 400,000 customers in west Texas and southern New Mexico, also broke a record it set last summer. The utility said in a statement that conversions to refrigerated air conditioners, population growth and hotter weather have led to "consistent new annual peak loads in 16 out of the last 17 years." Temperatures in El Paso reached 109 degrees on Thursday, the day the demand record was set — one degree shy of the all-time high temperature for that day, and 12 degrees above average.

Dangerous heat scorched California, too, with cities from Sacramento to Palm Springs sweltering in near-record temperatures. In Roseville, a city of more than 125,000 people north of Sacramento, the municipal utility saw 4 percent more electricity demand than it had ever seen before. Turlock Irrigation District — a Central Valley water agency that also sells electricity to nearly 100,000 homes and businesses — found itself providing 644 megawatts of power on Monday, surpassing a previous high of 608 megawatts.

Turlock spokesperson Calvin Curtin said the utility was never worried about running out of power. Turlock has a diverse portfolio of energy sources, many of which are climate-friendly: The utility owns a 62-turbine wind farm along Washington's Columbia River and buys solar power from a 54-megawatt project in nearby Kern County. It owns gas-fired power plants and buys a slice of the output from the Boardman coal plant in Oregon, too. Turlock also owns two-thirds of the hydropower plant at Don Pedro Dam, which has been pumping out more electricity than usual following California's wet winter.

Last week's demand record, Curtin said, "was really an interesting footnote more than it was a real concern" for Turlock.

"It was hotter than heck here on Tuesday, so no doubt that we were going to set a record," he said.

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Other utilities that set electricity use records included Imperial Irrigation District in inland Southern California — which surpassed its previous high mark amid temperatures that reached 123 degrees in parts of its service territory — and Arizona's Trico Electric Cooperative, which broke its old record several times by the end of the week.

Southern Nevada's Overton Power District No. 5 tied its peak demand record and set a new high mark for June as temperatures soared to 117 degrees. Several other utilities set monthly records, including Sacramento Municipal Utilities District and Modesto Irrigation District in California's Central Valley, which saw its second-most demand ever.

The Lone Star State also set a monthly record — twice. The Electricity Reliability Council of Texas, or ERCOT, which manages the power grid for most of the state, reported 67,512 megawatts of demand on Friday afternoon, beating the previous high mark for June by nearly 1,000 megawatts. The new record didn't even last two hours.

ERCOT expects to break its all-time demand record of 71,110 megawatts this summer, potentially reaching close to 73,000 megawatts, spokesperson Leslie Sopko said.

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Auffhammer, the UC Berkeley professor, calculated as part of his recent study that utilities may need to spend $180 billion by the end of the century building gas-fired power plants to meet electricity demand on the hottest days if action isn't taken to slash planet-warming carbon emissions. But there are cheaper options than building new gas plants, Auffhammer said. If society invests in energy-efficient appliances and develops cheaper batteries — which can store energy from solar and wind farms for times when the sun isn't shining and the wind isn't blowing — the costs could be much lower.

President Donald Trump's administration has opposed those types of policies. The Department of Energy has delayed energy efficiency standards for portable air conditioners and other appliances that were finalized by the Obama administration, prompting lawsuits from 11 states and two environmental groups. Trump's budget proposal would cut billions of dollars for energy research, including battery storage.

"People like to have their lights on, and they like to be able to operate their air conditioner when they need it," Auffhammer said. "In order to make sure we're going to have these electricity services we need or these cooling services we want, we can either become more efficient or we can put more (power plants) online."

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Many southwestern utilities didn't set electricity-use records last week, despite the heat. For instance, the California Independent System Operator, which manages the grid for most of the state, saw demand of 44,200 megawatts on Tuesday — several thousand megawatts less than it expected, and far below its record peak of more than 50,000 megawatts, set during a July 2006 heat wave. California's overall electricity consumption has largely stayed flat over the last decade even as the state's population and economy have grown, partly due to energy efficiency standards for buildings and appliances.

California also gets more of its electricity from rooftop solar panels than almost any other state. The electricity demand figures reported by utilities don't include rooftop solar and other "behind-the-meter" energy technologies, such as home battery storage.

Sammy Roth writes about energy and the environment for The Desert Sun. He can be reached at sammy.roth@desertsun.com, (760) 778-4622 and @Sammy_Roth.