It’s too early to know whether the unseasonably warm March will ripple into higher summer electric bills across the state. A major factor could be rising temperatures in area rivers, which the Tennessee Valley Authority uses to cool its power plants.
TVA has to follow environmental rules for how warm water can be when it goes back to the river after it’s used to cool nuclear and coal facilities. If the water’s too hot, the plant will throttle back operations, leaving the power grid to draw electricity from elsewhere, which can drive up costs.
After a record-hot March, area rivers are warmer than usual. But TVA water manager David Bowling says that’s on the surface. TVA’s reservoirs can run to over a hundred feet deep, and draw water for cooling from the bottom, where it’s around ten degrees colder from winter. Bowling says that’s handy in summer when the turbines heat up.
“I won’t say that it’s not a concern, but right now it’s too early to predict what conditions are going to be like by the end of July or August. But we do measure how much cold water we have in storage and apportion that out throughout the summer.”
Bowling figures they’ll be able to put that cold water to work downstream this summer.
EXTRA: He says if spring brings a lot of rain, reservoirs can be forced to dump cold water to make room for new runoff, which is warmer. But so far that hasn’t been the case this year — Bowling says rainfall has been about 91 percent of what was expected.
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