The Tennessee Valley Authority called for temporary energy load reductions or rolling blackouts as some call them, to stabilize the regional power grid for the first time in its 89-year history amid subzero temperatures Friday morning.
TVA Chief Operating Officer Don Moul told The Tennessean Friday the power operator had to reduce strain on its grid as demand for energy ran nearly 35% higher than expected on a normal winter day, while at the same time a few of its coal and gas energy facilities were down because of the freezing temperatures.

“We’re restored a number of those in each category, but we will still have some work to do to build additional margin,” Moul said.
TVA is working to build up some of its energy margins as temperatures settle into the high single digits and low teens across the state.
“We’re optimistic, but also realistic,” Moul said. “We have some real cold temperatures through the next 48 hours, and we’re expecting peak [energy use] in the evening tonight into tomorrow morning, similar to what we’ve already seen.”

Last year, TVA said it could take temperatures of negative 10 across the Tennessee valley for it to have to use all of its generations at once, and still, rolling blackouts would be unlikely unless a nuclear unit suddenly went offline. A nuclear plant did not go offline, but Moul said the temperatures were some of coldest ever recorded by TVA in Tennessee in its history.
“The National Weather Service has called this a once-in-a-generation event,” Moul said. “So, pretty extreme conditions.”