Brutal US heat dome threatens July 4, World Cup weekend; 100°F in New York

A scorching heat dome will push electricity demand in the eastern US to record levels over the July 4 holiday, testing power grids as air conditioners run at full capacity on a busy World Cup weekend.

A dangerous heat wave is forecast to bring triple-digit temperatures to many American cities, including New York. More than 180 million people from Kansas to Maine were under an extreme heat watch or warning Friday, according to the U.S. Weather Forecast Center. Heat advisories stretch from Michigan to southern Alabama.

“It’s looking pretty oppressive today,” Frank Pereira said by phone, with “significantly above-normal temperatures from the Plains and Midwest to the Mid-Atlantic and Northeast.”

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Hundreds of temperature records — for daytime highs and warm nighttime lows — are likely to be tested over the weekend, according to the U.S. Weather Forecast Center. That’s straining power systems across the region, with more than 71,000 customers without power just before 8:30 a.m. New York time, data from PowerOutage.com shows.

The nation’s largest network, serving nearly a fifth of Americans from Washington to Chicago, has been operating in emergency mode — the lowest of three levels — for the third day in a row. PJM Interconnection LLC has ordered all power plants to be available at maximum levels throughout the day as it faces a capacity crunch.

“PJM is not in distress for any reason other than power outages,” said Adam Sinn, managing director of hedge fund Aspire Commodities. The Mid-Atlantic region, including data centers concentrated in northern Virginia, saw about 9.5 gigawatts of generation outages, compared with previous forecasts that showed less than a third of that, he said.

While electricity use is expected to ease slightly on Friday amid holiday travel, demand for cooling could pick up again as hot and humid conditions persist. The risk of breakdowns in power plants or other critical equipment increases with high sustained demand.

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The sprawling heat dome adds another major complication: grids that typically rely on each other for back-up supplies can limit supplies to neighbors to keep their systems stable.

Temperatures in Central Park soared to 100 degrees Celsius (38°C) on Thursday, the city’s hottest day since 2012. Records were set from Caribou, Maine to Chattanooga, Tennessee, including Boston, Baltimore’s Inner Harbor and Washington’s Reagan National Airport, Pereira said. Unseasonable temperatures and humidity are forecast for the weekend across the city and the eastern half of the US.

Consolidated Edison Co., which runs New York’s electric utility, asked about 133,000 customers in northern Brooklyn to conserve power and allow crews to repair equipment. The voltage was reduced by 8% so they could do it safely and limit the power flows. Those households have been asked not to use washing machines, dryers and microwave ovens and to use only one air conditioner if they have two, the company said in a statement.

Daily highs in Philadelphia on Friday are expected to reach 99 degrees Celsius, according to weather models from the US and the European Center for Medium-Range Weather Forecasts. The city will host the World Cup match between France and Paraguay on Saturday.

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Similar temperatures are also set for Washington and Newark. Brazil will play Norway at Metlife Stadium in New Jersey on Sunday.

PJM, which operates a network serving an alley of data centers in Washington and northern Virginia, expects demand to climb to about 160.9 gigawatts at 5 p.m., down from Thursday’s peak of about 162.4 gigawatts. The grid operator had previously predicted that consumption could surpass the 2006 record of around 165.6 gigawatts, but demand has fallen due to emergency measures.

The most expensive hour for wholesale electricity prices on the PJM grid will be $739.04 per megawatt hour from 7 p.m., down 40% from Thursday’s high of $1,219.91.