Climate Change and Federal Hydropower

A report projects the effects of climate change on federal hydropower through the end of the twenty-first century

The Mt. Shasta Dam and Reservoir

Federal hydropower dams, like the Mt. Shasta Dam shown here, contribute 40 percent of the total hydropower generating capacity in the United States. 

Hydropower is the dominant source of renewable energy in the United States and provides around four percent of all U.S. electricity generation. Across all hydropower plants in the United States, 132 federal hydropower projects contribute 40% of the total hydropower generating capacity, and the revenues support reservoir operations that provide critical services such as flood control, water supply, and navigation. Climate change is expected to alter water resources in the future, which has implications for hydropower generation and planning. An assessment from Oak Ridge National Laboratory, Pacific Northwest National Laboratory, and Texas A&M University provides insights into the possible effects of climate change on federal hydropower generation through the end of the century.

As directed by Section 9505 of the SECURE Water Act of 2009 and managed by the Department of Energy Water Power Technologies Office, researchers reported their findings in The Third Assessment of the Effects of Climate Change on Federal Hydropower. The assessment addresses the long-term effects of climate change on federally generated hydropower by looking at future seasonal and annual trends in key hydrologic and meteorologic variables across four regions of the United States. This research extends the two prior assessments completed in 2012 and 2017 by incorporating multiple models of future climate scenarios and the latest global climate projections. PNNL’s Nathalie Voisin, Tian Zhou, and Wenwei Xu contributed expertise in advanced mapping and process-based representation of water management and hydropower on a large scale to inform the projections and estimate uncertainty in a novel way. The multi-model framework approach offers more nuanced insights into the possible climate change effects on hydropower resources through the end of the century. These results will be shared with Congress to inform future hydropower planning.