For many of us, cold weather tends to slow us down a bit, causes us to stay inside, accumulate more calories from all those holiday cookies.
But for nuclear energy facilities (and other thermal plants) cold weather means a higher efficiency – and that means more electricity generated.
Columbia is more efficient in the winter from the results of colder circulating water flowing through the condenser from the cooling towers. The winter months increase the cooling tower’s heat transfer effectiveness by removing more heat from the circulating water. The circulating water flows to the condenser and absorbs the waste heat from the steam used by the turbines. As the heat is being absorbed, the backpressure of the condenser is lower. Lower backpressure allows more energy to be removed from the steam in the turbines which in turn produces more electrical power.
So what does that mean for Columbia? On a recent cold day in November Columbia produced an extra 130 megawatt hours of electricity – just from the cold weather.
What about the vapor?
We know the air is getting chilly around here because the water vapor cloud above Columbia’s six cooling towers starts getting more and more visible. Here’s what John Z. says is happening there:
The clouds created by the cooling towers are water vapor entering the atmosphere. The visible cloud is the same process as seeing your breathe during the winter. As you exhale out, or cooling towers blow out water vapor, the water vapor starts to lose energy due to cold temperatures and the molecules start to pact together. The water vapor condenses into tiny water droplets forming a cloud. As for the summer, the warm air provides the energy to keep the water vapor as a gas resulting in a less visible or non-existent cloud.
While we love seeing the cloud, we do love those warm, sunny Tri-City summers.
(posted by John Dobken)