The massive drought parching the western U.S., and in the Colorado River basin in particular, is causing major concerns for the long-term reliability of hydropower generation. Hydroelectric dams produced 16% of the West’s electricity last year and 53% of the renewable energy supply. As climate change, mainly caused by the extraction and combustion of fossil fuels, makes droughts and extreme heat worse and more frequent, the loss of hydropower generation could exacerbate problems for the already-stressed power grid. (In August 2020, a shortfall of just 0.5% of total demand caused California’s first rolling blackouts in the state in nearly two decades.)

“It’s our largest low- or no-carbon emissions energy source that we can turn on and off when we need it,” Adrienne Marshall of the Colorado School of Mines told The Sun. “At the same time, our ability to generate hydropower is significantly threatened by drought.”  (The Colorado Sun, The Conversation; Climate Signals background: Western U.S. megadrought, Extreme heat and heatwaves)