Cooling ponds can freeze in winter, but whether they do depends on the local climate, the size of the pond, and the amount of heat being released into the water from the power plant. In colder regions, surface ice can form, especially along the edges of the pond where the water is shallow and less affected by heat from the plant. However, because power plants discharge warm water into the pond during operation, this heat can keep large portions of the pond from freezing completely.
The warmer water usually rises to the surface and mixes with the colder layers, helping prevent thick ice formation. Even when ice forms on the surface, the water beneath can remain liquid and continue to circulate, allowing the pond to perform its cooling function. If freezing becomes too extensive, it may reduce the efficiency of the cooling process, so some plants use mechanical systems or design features to help keep the water moving and limit ice buildup.
