ENERGY SECURITYRivers Are the West’s Largest Source of Clean Energy. What Happens When Drought Strikes?

By Syris Valentine

Published 30 April 2024

With rivers across the West running low, utilities must get creative if they are to meet demand without increasing emissions.

In Washington, a dozen dams dot the Columbia River — that mighty waterway carved through the state by a sequence of prehistoric superfloods. Between those dams and the hundreds of others that plug the rivers and tributaries that lace the region, including California and Nevada, the Western United States accounts for most of the hydroelectric energy the country generates from the waters flowing across its landscape. Washington alone captures more than a quarter of that; combined with Oregon and Idaho, the Pacific Northwest lays claim to well over two-fifths of America’s dam-derived electricity. So when a drought hits the region, the nation takes notice.

That happened in 2023 when, according to a recent report, U.S. hydroelectric power hit its lowest level in 22 years. While the atmospheric rivers that poured across California provided the state with abundant energy, the Pacific Northwest endured low summer flows after a late-spring heat wave caused snowpack to melt and river levels to peak earlier than normal. Though dam turbines kept spinning throughout the year — proving that even during a drought the nation’s hydro system remains reliable — last year offered energy providers in the West a glimpse of the conditions they may need to adapt to as the world warms and seasonal weather patterns shift.

While models predict climate change will plunge California and the Southwest deeper into drought, what awaits Washington and Oregon is less clear. The Pacific Northwest will get warmer. That much is certain. But in terms of the rain that places like Seattle and Portland are known for, things get fuzzier.

“Whenever you bring in water precipitation and you’re looking at climate model results, they go in all directions,” said Sean Turner, a water resources and hydropower engineer with Oak Ridge National Laboratory. The Evergreen and Beaver states could get drier or wetter — or both, depending on the time of year.

Nathalie Voisin, chief scientist for water-energy dynamics at the Pacific Northwest National Laboratory, said much of the latest research suggests an increase in total annual hydroelectric power in the region, but, as Turner noted as well, uncertainties remain. “So as a trend, we see an increase” in annual precipitation, Voisin said, “but we also see an increase in variability of very wet years and very dry years.”