One way that some industries increase profits is by unloading some of their costs onto the environment through pollution. These unloaded costs are referred to as externalities. Factory and fossil fuel power plant pollution coming from the smoke stacks is one of these externalities. There is another type of externality coming from thermoelectric power plants which require huge amounts of cooling water to turn steam back into water as part of the energy generation cycle. It does not matter whether coal or nuclear energy is used to produce the steam that turns the turbines. This “thermal” pollution is not discussed as often as the toxic particulates and gases emitted by smokestacks but it real and it is serious.
Recently, there was a study of such pollution which included some computer simulations conducted by scientists at the University of New Hampshire. This is the first comprehensive study of how such thermal pollution from power plants affects the climate, hydrology and aquatic ecosystems in the Northeaster United States. The rivers have become “horizontal cooling towers” analogous to the vertical cooling towers used at some power plants. This cooling process is very useful and free to the utilities running the power plants but it is costly to the environment.
“The analysis, done in collaboration with colleagues from the City College of New York (CCNY) and published online in the current journal Environmental Research Letters, highlights the interactions among electricity production, cooling technologies, hydrologic conditions, aquatic impacts and ecosystem services, and can be used to assess the full costs and tradeoffs of electricity production at regional scales and under changing climate conditions.”
Thermoelectric power plants (including nuclear power plants) provide over ninety percent of the electricity in the United States. The amount of cooling water drawn from the environment is greater than the total amount of water currently used for agriculture in the United States. Some of the water is evaporated in huge vertical cooling towers and the rest is dumped back into the environment. The heat is dissipated as the rivers flow downstream from the power plants. About half of the water used for cooling thermoelectric power plants is returned to the rivers with the other half going into the atmosphere. Just over eleven percent of the heat from the power plants goes back into the atmosphere as the rivers flow away. All the rest of the heat is arrives at coastal bodies of water and the oceans.
While the flow of most of the 4,700 river miles is not impacted significantly by the power plants drawing water from the rivers, the impact of the heat on the ecosystem in general and fish habitats in particular is considerable. Recently, a nuclear power plant had to stop drawing water from Long Island Sound because the ocean temperatures were too high. And a nuclear power plant in Illinois had to be shut down because the water in a cooling pond became too hot to use.
With global climate change heating bodies of water and water levels of lakes, rivers and reservoirs dropping as more and more water is consumed, there are serious considerations that must be taken into account regarding the use of environmental surface water for cooling thermoelectric power plants.
Monticello Reservoir was built in South Carolina to provide cooling water to the Virgil C. Summer Nuclear Generation Station – picture by Duane Burdick:
