US power plants vulnerable to climate change

Posted by Kate Taylor

Climate change will hit nuclear and coal-fired power production in the US and Europe by forcing more temporary shutdowns, say researchers.

Warmer water and reduced river flows have affected 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.

And European and University of Washington scientists say that in the next 50 years thies sort of thing will become more common. They predict that thermoelectric power generating capacity from 2031 to 2060 will decrease by between four  and 16 percent in the US, and six 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.

"This study suggests that our reliance on thermal cooling is something that we're going to have to revisit," says Dennis Lettenmaier, a UW professor of civil and environmental engineering.

Thermoelectric plants, which supply more than 90 percent of US electricity, account for an astonishing 40 percent of the nation's freshwater usage. In Europe, they supply three-quarters of electricity and account for about half of freshwater use.

While much of this water is recycled, the power plants rely on consistent volumes of water, at a particular temperature, to prevent the turbines from overheating.

Reduced water availability and warmer water mean higher electricity costs and less reliability, with plants that rely on 'once-through cooling' the most vulnerable. The study highlights the Browns Ferry plant in Alabama and the New Madrid coal-fired plant in southeastern Missouri  as particularly at risk.

"The worst-case scenarios in the Southeast come from heat waves where you need the power for air conditioning," says Lettenmaier. "If you have really high power demand and the river temperature's too high so you need to shut your power plant down, you have a problem."

One strategy would be to reduce reliance on freshwater sources and place the plants near saltwater, says Pavel Kabat, director of the International Institute for Applied Systems Analysis in Austria.

"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 says.
 "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."