On November 15, 2011, the Energy in a Warming World Initiative, a three-year research collaboration between the Union of Concerned Scientists and more than a dozen scientists, issued a peer-reviewed report, “Freshwater Use by U.S. Power Plants: Electricity’s Thirst for a Precious Resource.”  The report is the first systematic assessment of power-plant water use, its relationship with fresh water systems and the low-quality of data currently available on the topic.  According to the report, power plants in the United States take in such large volumes of water for cooling that there is the potential to lead to severe price and capacity issues for energy generators. 

According to the report, because many power plants depend so heavily on water, there is a risk that they will have to cut back on electricity production at times when water is scarce.  This situation has already occurred in areas affected by severe drought and intense heat waves.  For instance, the 2011 Texas drought has put so much pressure on the water supply that operators have warned that if it continues into next year, power cuts on the scale of thousands of megawatts are possible.  The report also showed that power plants are stressing water bodies by discharging water at temperatures that are harmful to fish and other wildlife.  In recent years, a number of power plants have had to cut back power production because they were unable to stay within water temperature discharge limits.  Additionally, low-carbon electricity technologies that are preferred in renewable energy portfolios, such as nuclear and concentrating solar, can consume more water than traditional natural gas and coal plants.  In 2008, on average, “plants in the U.S. nuclear fleet withdrew nearly eight times more freshwater than natural gas plants per unit of electricity generated, and 11 percent more than coal plants.” 

The full report is available here