ENERGY SECURITYORNL Assessment Uncovers Hydropower Opportunities in Existing Dams
As much as 15.2 terawatt-hours of electricity could be generated annually at non-powered dams — enough to supply more than 1.4 million homes, according to an updated assessment of hydropower technical potential across the nation. Historically, only 3 percent of the dams in the United States have been used for power generation.
As much as 15.2 terawatt-hours of electricity could be generated annually at non-powered dams — enough to supply more than 1.4 million homes, according to an updated assessment of hydropower technical potential across the nation compiled by researchers at the Department of Energy’s (DOE) Oak Ridge National Laboratory (ORNL) and Idaho National Laboratory (INL).
Historically, only 3 percent of the dams in the United States have been used for power generation, with most serving purposes such as water storage, navigation and flood control. The remaining non-powered dams (NPDs) present an opportunity for domestic energy production. The recent assessment identified a total potential capacity of 4 gigawatts across a subset of more than 2,600 NPDs, with individual facilities averaging 1.5 megawatts.
Analysis of the technical potential of these NPDs revealed that federally owned dams account for 86 percent of total capacity in the candidate sites. The assessment also pinpointed regions such as the upper Mississippi River and Great Lakes as particularly promising for hydropower development due to the large number of projects with high potential power capacity.
“The potential is heavily concentrated in large, federally owned dams, but we also see many opportunities for utilities and local or state agencies,” said ORNL’s Carly Hansen, the project’s principal investigator and lead author of the report. “This refined data will help decision makers focus their efforts on the sites with the greatest possible capacity.”
Previous national assessments of untapped hydropower resources had estimated the theoretical capacity of NPDs between 12 and 30 gigawatts, but these estimates were hindered by a lack of detailed data and an incomplete representation of technical factors relevant to hydropower retrofits. The recent assessment addresses this gap by incorporating more sophisticated methodologies and detailed datasets, offering a clearer and more actionable picture of potential hydroelectric yield.
“This project was really motivated by the need to improve confidence in what’s technically possible,” said Hansen.
Harnessing Untapped Infrastructure
The assessment was conducted using a computational tool developed by INL called HydroGenerate, along with newly integrated daily records of streamflow — the rate at which water moves through channels such as streams and rivers. The model relies on inputs from long-term streamflow records such as the USGS stream gage network and the ORNL Dayflow reanalysis dataset, a resource that simulates runoff and routing of water through river networks to provide consistent estimates of streamflow across U.S. rivers.
