The water in Lake Powell, one of the nation's largest reservoirs, has fallen so low amid the Western drought that federal officials are resorting to emergency measures to avoid shutting down hydroelectric power at the Glen Canyon Dam.
The Arizona dam, which provides electricity to seven states, isn't the only U.S. hydropower plant in trouble.
The iconic Hoover Dam, also on the Colorado River, has reduced its water flow and power production. California shut down a hydropower plant at the Oroville Dam for five months because of low water levels in 2021, and officials have warned the same thing could happen in 2022.
In the Northeast, a different kind of climate change problem has affected hydropower dams — too much rainfall all at once.
The United States has more than 2,100 operational hydroelectric dams, with locations in nearly every state. They play essential roles in their regional power grids. But most were built in the past century under a different climate than they face today.
As global temperatures rise and the climate continues to change, competition for water will increase, and the way hydropower supply is managed within regions and across the power grid in the U.S. will have to evolve. We study the nation's hydropower production at a systems level as engineers. Here are three key things to understand about one of the nation's oldest sources of renewable energy in a changing climate.