How drought and heat threaten global electricity supply

Power plants need freshwater to produce electricity. But the future of our planet’s freshwater resources is murky. Increasingly common droughts and heat waves because of climate change will reduce the electricity production capacity of most of the world’s power plants, a new study published in the journal Nature Climate Change reports. The good news is that plant operators could adopt various strategies to combat this capacity reduction.

“We clearly show that power plants are not only causing climate change, but they might also be affected in major ways by climate,” said Keywan Riahi, the energy program director at the International Institute for Applied Systems Analysis (IIASA) in Austria, and a co-author of the study, in a press release.

Hydropower and thermoelectric—which include nuclear, coal, gas, biomass and geothermal—power plants produce 98 percent of electricity worldwide. Hydropower plants harness the energy in falling or fast-flowing water to produce electricity. Thermoelectric plants, meanwhile, require freshwater mainly to cool and condense the steam that drives electricity-generating turbines.

The researchers investigated the impact of various climate-triggered changes in water resources on 24,515 hydropower plants and 1,427 thermoelectric power plants around the world. They did that by applying a global hydrological and electricity model to hydropower sources and thermal power plants that use river water for cooling.

The model shows that stream-flow reductions and increased water temperatures could reduce the generation capacity of up to 86 percent of thermoelectric power plants and up to 74 percent of hydropower plants. By 2050, those reductions could be, on average, 7 to 12 percent for thermoelectric plants and 1.2 to 3.6 percent for hydro plants. The United States, southern South America, southern Africa, central and southern Europe, Southeast Asia and southern Australia are especially vulnerable to these water resource changes, they found.

Now for the good news. For hydropower, the researchers calculated that increasing the hydropower plant efficiency by 10% could offset the capacity reduction. For thermoelectric plants, switching from coal to less water-thirsty natural gas plants, and switching from freshwater cooling to air or seawater cooling systems would be effective strategies.

The researchers recommend that the electricity sector should focus on climate change adaptation in addition to mitigation in order to sustain water-energy security in the future. Combining various adaptation options would be most effective, they note. – Prachi Patel | 07 January 2016

Source: Michelle T. H. van Vliet, David Wiberg, Sylvain Leduc & Keywan Riahi, Power-generation system vulnerability and adaptation to changes in climate and water resources. Nature Climate Change (2016) doi:10.1038/nclimate2903

Image © zhangyang13576997233,