Nearly two-thirds of the U.S. is expected to be hit by a massive weekend heat wave, forcing energy companies to brace for maxed out grids and potential blackouts.

It will also create a spike in carbon emissions, as the use of fossil fuels by people seeking to cool down expands.

In Texas, the Midwest, the mid-Atlantic and New England, states are facing historic heat advisories, with temperatures expected to reach into the 100s in some places.

ADVERTISEMENT

Some

that more than 85 percent of the lower 48 states will experience temperatures of at least 90 degrees between Friday and Tuesday. Almost 50 percent of those states will experience temperatures higher than 95 degrees.

All of that will lead to spikes in energy use.

“A lot of Americans don’t really have a deep understanding of the energy they are using and the fact that time of the day and peak energy is peak fossil fuel use. It’s a double whammy in terms of climate,” said Kiran Bhatraju, CEO of Arcadia Power.

Increasing temperatures will likely result in increased air conditioning usage, a phenomenon power companies are keeping an eye on to make sure energy demand doesn’t exceed availability.

New York’s Independent System Operator said it’s expecting peak energy loads between Friday and Sunday in excess of 30,000 megawatts (MW).

“The NYISO’s grid operators are ready to handle the expected demand,” Wes Yeomans, vice president of operations for NYISO, said in a statement.

“We are coordinating with local transmission operators to suspend planned maintenance work through the event and are in regular contact with generation owners to ensure we meet the reliability needs of the grid.”

Energy concerns in New York are especially heightened after the city faced an hours-long blackout last weekend. A transformer fire caused that issue.

New York’s Con Edison is prepared for “scattered outages” across Manhattan and Brooklyn, Queens and the Bronx, the company told USA Today Tuesday.

In Washington, D.C., which is expected to see temperatures as high as 101 degrees on Sunday, grid operators are also feeling the stress.

Christina Harper, a spokeswoman for Pepco said that by noon Friday Washington had already experienced an increased energy demand of 13 percent compared to the average daily usage this time last year.

Friday afternoon, power grids across the country largely appeared to be meeting their demand, but some systems showed strain. In Texas, the demand for energy was more than 1 percent higher than forecasted availability. In New York, demand was almost 1 percent over availability, according to real-time data from the U.S. Energy Information Administration.

Some scientists say the temperature spikes experienced across the country are likely exacerbated by climate change, with extended and dramatic heat periods happening more frequently.

This week’s temperatures are just one of a series of notable heating trends that have hit the globe this year. This past June was the hottest June in recorded history, with cities across Europe especially feeling the strain.

And the rising temperatures will also ultimately lead to more fossil fuel use, as U.S. electric grids remain largely powered by the nonrenewable energy sources of coal and gas.

“There’s this ugly climate feedback loop that is powered by fossil fuels. The more and more we burn, the more extreme heat and cold events will get,” said Bhatraju, of Arcadia Power, a nationwide digital utility that focuses on getting cheaper renewable energy sources for its customers.

New England’s ISO real-time grid on Friday showed the region was powering 65 percent of its grid with natural gas. Nuclear energy was the second biggest contributor, with coal making up two percent of the energy mix. Renewables contributed just 7 percent of the energy.

In New York, oil and gas accounted for around 57 percent of energy generation in the state. Nuclear followed at 20 percent with renewables like hydropower, wind and solar making up 21 percent of the energy sources.

Weather events also often lead to a spike in energy costs. For example, Bhatraju said that during the Polar Vortex episode that brought freezing temperatures across the U.S., energy prices spiked by nearly 1,000 percent. He said to expect similar price spikes this week.

“In a week like this where it’s not isolated, it’s going to be two thirds of the [energy] use,” Bhatraju said.

"You are going to see significant price spikes."