The global warming trends that cause many consumers to increase their electricity consumption for cooling applications are also taking a toll on power generators. Thermal power stations responsible for the bulk of electricity produced worldwide reduce their electricity output on hot days due to cooling limitations. On the hottest days, power plant capacity can be reduced by more than 10% because the air and water used to cool the plants is too warm.

The emergence and implications of these thermal power generation trends were analyzed by researchers from Syracuse University and Dartmouth College, noting that a global temperature rise of 2° C could double power (top) Power stations in the U.S. and European Union providing daily outage data. (bottom) Monthly maximum temperature over the pre-industrial period (1850-1900, blue), in 1981-2018 (black) and projected under 2° C (orange) and 4° C (red) warming scenarios. Source: Ethan David Coffel et al.plant outages on hot days from current levels. Water-based primary cooling systems used in these facilities become less efficient at higher ambient temperatures. When ambient air or water temperatures are warm or when water availability is low, thermal power plants must curtail electricity output or shutdown due to the inability to dissipate heat fast enough.

Daily-scale thermal power plant outage data available for nuclear plants in the U.S. and coal, gas, and oil plants in the European Union was analyzed together with historical daily-scale temperature and monthly-scale runoff trends to examine the sensitivity of thermal power plant capacity to heat and water availability. Results published in Environmental Research Letters indicate that power plant curtailment could exert substantial impacts on global electricity generation capacity during the hottest parts of the year, necessitating additional overbuilding of the global electricity system by up to 7% given the current generating technology mix.

A rapid transition to solar, wind and other non-thermal power sources could greatly reduce the risk of curtailment as well as the greenhouse gas emissions driving climate change.