STUDY: CLIMATE CHANGE COULD CUT OUTPUT IN THERMOELECTRIC POWER PLANTS UP TO 19% BY 2060

Farris Willingham
GHG Monitor
06/08/12

The generating capacity of thermoelectric power plants in the United States could decline by up to 19 percent between 2031 and 2060 due to warmer temperatures and reduced river flows, according to a study published in the most recent issue of Nature Climate Change. Fossil fuel and nuclear-fired power plants, which currently account for 91 percent of the country’s electricity production, rely on a consistent stream of water to function properly. Plants utilize cooling towers or ‘once-through cooling’ systems to draw in water from nearby sources to keep the facility cooled, with water eventually being returned to the source at a higher temperature. Climate change is expected to cause the substantial warming of bodies of water like rivers and streams, sources that plant operators are reliant upon for their electric generating unit to function at full capacity. “Changes in water availability and surface water temperature directly affect thermoelectric power generation potential and reliability,” the study reads.

Researchers observed 61 power plants located in the central and eastern portions of the U.S., testing daily water temperatures and river flow projections along with plant-specific data such as cooling system efficiency and environmental restrictions, in order to quantify the impacts of climate change on thermoelectric capacity. The authors then created two scenarios—one where power plants experience a slow technological change and another that assumes the adoption of renewable technologies. “Owing to the smaller adaptive capacity of the thermoelectric sector [under the slow change] scenario, the vulnerability to climate change will be substantially higher for the [slow change scenario] when compared with the [high renewables] scenario,” the study says. The authors found that taking into account projections for climate change and water temperature rises, the generating capacity of thermoelectric power plants in the country could decline by 6 to 19 percent between 2031 and 2060. Co-author Dennis Lettenmaier, a University of Washington professor, said the study shows that a transition in the type of cooling technologies is needed in the near future for thermoelectric power plants. “As those things get to their design lifetime, there becomes a decision about what to do in terms of replacing them,” he said in an interview with GHG Monitor.

Warming Could Cause Supply Shortages

The authors of the study highlighted some of the problems that this reduced efficiency can cause. “The limited supply of electricity in combination with increased production costs lead to significant rises in electricity price,” the authors wrote in the study. “In the U.S. a similar event in 2007–2008 caused several power plants to reduce production, or shut down for several days owing to a lack of surface water for cooling and environmental restrictions on thermal discharges.”

Problems are deepened due to the Clean Water Act, which restricts the amount of water unit operators will be able to withdraw and the temperatures for discharge, according to the study. Those regulations create a host of problems for the power plants, Lettenmaier said. “The critical thing there is that the time when the cooling water issues become most critical for these power plants is when the demand is maximum, like in southeastern U.S. during the summertime when river flows are low and temperatures are high,” he said. 

The study recommends a few possible solutions for reducing a plant’s vulnerability to climate change. “Dry cooling systems or non-freshwater sources for cooling are possible alternatives but may be limited by locally available resources and have costs and performance disadvantages,” according to the study. Another potential solution is for power plants to switch to natural gas generation. “Considering the projected decreases in cooling-water availability during summer in combination with the long design life of power plant infrastructure, adaptation options should be included in today’s planning and strategies to meet the growing electricity demand in the twenty-first century,” the study reads.