More than 2,500 dams in the U.S. provide 78 GW of conventional and 22 GW of pumped-storage hydropower. But the nation also has more than 80,000 dams that do not produce electricity—facilities that, if outfitted with hydroelectric power plants, could generate an estimated 12 GW and increase existing U.S. conventional hydropower capacity by roughly 15%, the Department of Energy (DOE) says in a new report,

“Importantly, many of the monetary costs and environmental impacts of dam construction have already been incurred at [non-powered dams (NPDs)], so adding power to the existing dam structure can often be achieved at lower cost, with less risk, and in a shorter timeframe than development requiring new dam construction,” suggests the report, titled An Assessment of Energy Potential at Non-Powered Dams in the United States. “The abundance, cost, and environmental favorability of NPDs, combined with the reliability and predictability of hydropower, make these dams a highly attractive source for expanding the nation’s renewable energy supply.”

The report from the DOE’s Wind and Water Power Program is essentially a national-scale analysis of U.S. dams to determine the ability of NPDs to provide hydroelectric power. Of the more than 80,000 NPDs throughout the U.S., 54,391 dams were analyzed, with remaining dams eliminated from consideration due to erroneous geographic information, or erroneous flow or drainage area attributes that could not be resolved and corrected through independent investigation of maps and records. Dams with a reported height of less than five feet were also excluded from analysis.

A majority of the NPD hydroelectric potential is concentrated in just 100 NPDs, which could contribute approximately 8 GW of hydropower. “The top 10 facilities alone could add up to 3 GW of new hydropower,” the report says. “Eighty-one of the 100 top NPDs are U.S. Army Corps of Engineers (USACE) facilities, many of which, including all of the top 10, are navigation locks on the Ohio River, Mississippi River, Alabama River, and Arkansas River, as well as their major tributaries.”

The top three hydrologic regions are the Ohio, Upper Mississippi, and Arkansas-White-Red. The greatest amount of hydropower potential is found in Alabama, Arkansas, Illinois, Kentucky, Pennsylvania, Texas, and Louisiana—mainly due to a series of Ohio River locks and high river flows. Dams owned by the U.S. Bureau of Reclamation also hold the potential to add approximately 260 MW of capacity.

The study was funded by the Office of Energy Efficiency and Renewable Energy and produced by Oak Ridge National Laboratory in partnership with Idaho National Laboratory. 

According to the DOE, the study is one of a number of nationwide resource assessments being conducted by the Energy Department to assess how U.S. hydropower capacity can be expanded. Preliminary results indicate that by 2030, 15% of the nation’s electricity could come from water power – including hydropower and marine and hydrokinetic energy sources, such as waves and tides.

Sources: POWERnews, DOE