How one "mega drought" strains clean energy sources

December 6, 2022 / 3 min read

Each year, Verisk’s Emerging Issues team works closely with students and faculty at several university insurance and risk management departments on research projects to help nurture the next generation of insurance talent. In one of our most recent collaborations, Illinois State University’s Joseph Schuetz helped explore the increasingly worrisome implication of the drought in the Western United States and its potential impact on the U.S. power grid.

The drought isn’t simply a dagger pointed at the heart of hydropower—it threatens nuclear plants as well.

Water, water nowhere

The water supply is decreasing rapidly in the Western United States in the face of extreme drought. ¹² In fact, the whole region seems to be facing aridification—its climate generally becoming much drier than it has been in the past.³ The consequences of this so-called “mega drought” will likely be significant, including the already evident strain it’s placing on hydropower generation.⁴ Many hydroelectric dams are at risk of significantly decreased output or of shutting down entirely due to decreasing water levels in dams.⁵ Dam shutdowns could have major consequences for power generation and the electrical grid in the West.

But the drought isn’t simply a dagger pointed at the heart of hydropower—it threatens nuclear plants as well.

Dried out

The West has endured a 22 year period of scorching drought conditions not seen in the region for at 1,200 years.⁶

Drought conditions in the year 2020. The U.S. Drought Monitor is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture, and the National Oceanic and Atmospheric Administration. Map courtesy of NDMC.

Drought conditions in the year 2021. The U.S. Drought Monitor is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture, and the National Oceanic and Atmospheric Administration. Map courtesy of NDMC.

Thanks to the expanding radius of the current drought, most of the hydropower plants in the Western United States are in an area with severe drought or worse, as the map below from the U.S. Drought Monitor demonstrates.

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As the water goes, so goes the power.

Hydropower electricity generation in the United States has generally been falling over the past several years and in 2021 dropped by 14 percent from the previous year.⁷ Hydropower plants serving millions of people are already facing decreased power output and, in some cases, have already been forced to shut down completely due to decreasing water levels.⁸

Credit: NASA’s Earth Observatory

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Credit: NASA's Earth Observatory

Drought puts the pinch on nuclear power

Even nuclear plants are at risk as the mega drought grinds on and water sources dry up. It may not be immediately obvious, but nuclear plants consume their fair share of water—an average of 30 million gallons an hour.⁹ This water, used to cool fuel rods, needs to be at a certain temperature during intake so that it can be safely released back into surrounding water—and climate change is helping to heat this water to often unacceptable levels.¹⁰ When the intake water is too hot, nuclear plants can be forced to suspend operations, putting additional strain on the grid.¹¹

Drought and disruption

Consumers and businesses may be faced with rising energy costs and supply disruptions as the mega drought drags on. For example, when just one nuclear power plant in Tennessee was forced to reduce output due to high water temperatures, it cost customers north of $50 million over eight weeks.¹² One study examining the ramification of hydro plant closures estimated a 2.5 to 2.7-fold increase in energy costs.¹³

The power grid in the West will likely be under major drought stress in the coming years as the drought persists and the planet warms. Indeed, there’s a grim irony at work: the reliability and promise of green energy such as hydro is actually being threatened by the warming generated by the fossil fuel energy sources it’s trying to replace.

“Water Supply,” U.S. Drought Monitor, https://www.drought.gov/topics/water-supply. Accessed on October 27, 2022.
“Drought in the Western United States,” United States Department of Agriculture, July 11, 2022. https://www.ers.usda.gov/newsroom/trending-topics/drought-in-the-western-united-states/. Accessed on October 27, 2022.
Jonathan T. Overpeck & Bradley Udall. (May 19, 2020) “Climate change and the aridification of North America”. https://www.pnas.org/doi/abs/10.1073/pnas.2006323117
https://www.reuters.com/business/sustainable-business/inconvenient-truth-droughts-shrink-hydropower-pose-risk-global-push-clean-energy-2021-08-13/ A. Park Williams, Benjamin I. Cook & Jason E. Smerdon (February 14, 2022) “Rapid intensification o of the emerging southwestern North American megadrought in 2020-2021”. https://www.nature.com/articles/s41558-022-01290-z
https://www.reuters.com/business/sustainable-business/inconvenient-truth-droughts-shrink-hydropower-pose-risk-global-push-clean-energy-2021-08-13/
https://www.scientificamerican.com/article/western-megadrought-is-the-worst-in-1-200-years/
https://www.hydroreview.com/environmental/u-s-hydropower-generation-to-decline-14-in-2021-amid-drought-eia-reports/
https://www.wsj.com/articles/west-risks-blackouts-as-hydroelectric-power-dries-up-11624008601
https://www.fastcompany.com/1746753/the-big-thirst-how-is-japans-fukushima-nuclear-plant-making-radioactive-water
Alan Neuhauser. (7/1/19) “Nuclear Power, Once Seen as Impervious to Climate Change, Threatened by Heat Waves”. https://www.usnews.com/news/national-news/articles/2019-07-01/nuclear-power-once-seen-as-impervious-to-climate-change-threatened-by-heat-waves
Ibid.
Alyson Kenward. (4/10/11) “In Tennessee, Heat Waves Diminish Nuclear Power Output”. https://www.climatecentral.org/news/in-tennessee-heat-waves-frustrate-nuclear-power
GCI Power Study https://www.glencanyon.org/wp-content/uploads/2018/05/GCI-Power-Study-Overview-Full.pdf