June 4, 2012
Thirsty Power Plants Hog Water
Michael Crumbliss for redOrbit.com
Often left out of the discussion on climate change is the effect that it will have on power production. 90% of US electricity production is dependent on huge amounts of water for cooling and steam, including all nuclear and fossil fuel power plants (though natural gas plants use less than coal). These power plants account for 40% of US freshwater use. In Europe these power plants provide 75% of power and use half the water.A study by European and University of Washington scientists published today in Nature Climate Change projects that in the next 50 years warmer water and lower flows will lead to more such power disruptions. The authors predict that thermoelectric power generating capacity from 2031 to 2060 will decrease by 4 to 16 percent in the U.S. and 6 to 19 percent in Europe due to lack of cooling water. The likelihood of extreme drops in power generation – complete or almost-total shutdowns – is projected to almost triple.
Warmer water and reduced river flows in the United States and Europe in recent years have led to reduced production or temporary shutdown of several thermoelectric power plants. For instance, the Browns Ferry Nuclear Plant in Alabama had to shut down more than once last summer because the Tennessee River's water was too warm to use it for cooling.
"This study suggests that our reliance on thermal cooling is something that we're going to have to revisit," said co-author Dennis Lettenmaier, a UW professor of civil and environmental engineering in a recent press release.
Reduced water availability and warmer water, caused by increasing air temperatures associated with climate change, mean higher electricity costs and less reliability.
While plants with cooling towers will be affected, results show older plants that rely on "once-through cooling" are the most vulnerable. These plants pump water directly from rivers or lakes to cool the turbines before returning the water to its source, and require high flow volumes.
The study projects the most significant U.S. effects at power plants situated inland on major rivers in the Southeast that use once-through cooling, such as the Browns Ferry plant in Alabama and the New Madrid coal-fired plant in southeastern Missouri.
Discharging water at elevated temperatures causes yet another problem: downstream thermal pollution.
"Higher electricity prices and disruption to supply are significant concerns for the energy sector and consumers, but another growing concern is the environmental impact of increasing water temperatures on river ecosystems, affecting, for example, life cycles of aquatic organisms," said first author Michelle van Vliet, a doctoral student at the Wageningen University and Research Centre in the Netherlands.
One adaptation strategy would be to reduce reliance on freshwater sources and place the plants near saltwater, according to corresponding author Pavel Kabat, director of the International Institute for Applied Systems Analysis in Austria and van Vliet's doctoral adviser.
"However, given the life expectancy of power plants and the inability to relocate them to an alternative water source, this is not an immediate solution, but should be factored into infrastructure planning," he said. "Another option is to switch to new gas-fired power plants that are both more efficient than nuclear- or fossil-fuel-power plants and that also use less water."