Rapid Response: CNN Fails to Provide Context on Heat Waves, Droughts and Power Plants, July 31, 2012
CNN has aired a report in which it failed to provide context on the water needs of power plants that draw cooling water from lakes, rivers and the ocean. Though all thermal power plants—coal, natural gas and nuclear—use water for cooling purposes, CNN focused solely on nuclear energy facilities.
It also did not mention the electric sector's positive track record for maintaining power production during severe heat waves. Specially, nuclear power plants in many regions suffering extreme heat safely produce electricity 24/7 to keep consumers cool and businesses operating.
Thermoelectric power generation is among the smallest consumptive uses of freshwater by any economic sector, at 3 percent of total consumption—about one-half of residential consumption. According to the U.S. Geological Survey, thermoelectric power generation accounts for 3.3 percent of freshwater consumption nationwide, about the same percentage as the industrial sector (3.4 percent) and raising livestock (3.2 percent). These power plants withdraw more water than any other economic sector, but they return 98 percent of the water they withdraw back to the natural source. Among electricity sources, certain renewable energy systems exceed thermoelectric power plants in water consumption.
Here is a detailed look at the CNN report.
Myth: Only Nuclear Power Plants Need a 'Significant Supply' of Water
The CNN report left the impression that only "...nuclear power plants depend on a significant supply of reliable water to cool reactors." The report failed to mention that all fossil fuel (coal, oil, natural gas) plants need large amounts of water to operate.
Nuclear power plants, like all thermal power plants, require significant amounts of water to generate electricity. Companies that operate nuclear power and fossil fuel plants have temperature limits, set by state environmental regulators, for water they discharge from their facilities back into local water bodies. As these water bodies get warmer during heat waves, these facilities may have to cut back on power production in order to meet those limits.
However, this is very rare for nuclear power plants. In fact, nuclear power plants have a track record of keeping electricity flowing even during record-setting heat waves.
Consider these facts:
The United States experienced 170 high temperature records in June. During that month, America's nuclear power plants—which follow stringent temperature limits on heat discharge—operated at an average of 90 percent capacity factor. Capacity factor is the ratio of the actual energy produced to the maximum possible during a given time period.
Severe, prolonged heat had a negligible effect on power production from nuclear power plants.
Nuclear power plant water use is comparable to coal plants. Natural gas plants use less water. (For water usage rates of different electricity generating sources, see the NEI study on water use below).
Power plants observe the temperature limit of their discharge water as set by the state regulatory authority, which determines the temperature that is safe for fish and plant life. Generally, nuclear energy and fossil-fuel plants return to full power when temperatures conditions in the water bodies allow it.
For more information, see the NEI article "How to Cool a Power Plant" and the NEI study "Water Use, Electric Power, and Nuclear Energy."
Also see NEI's blog for articles on water use during heat waves and droughts here and here.