U.S. Army Corps of Engineers Spends Millions Upgrading Aging Turbines and Transformers at Federal Hydroelectric Dams

U.S. Army Corps of Engineers is carrying out turbine and transformer upgrades at several of its 75 hydroelectric dams to extend their operating life and improve efficiency. The agency produces more than 70 billion kilowatt hours of electricity per year from these facilities.

Ice Harbor Lock and Dam on the Snake River in Washington State is nearing completion of a $47 million turbine renovation that began nearly 10 years ago. The dam, built in 1961, will have its third upgraded turbine online by summer 2026. Bill Dull, professional engineer for the USACE in the Walla Walla District, said modern computer-generated design can improve turbine efficiency by 3 to 5 percent over older methods.

Draft tubes at Ice Harbor are being reshaped with shotcrete, a cement mixture sprayed from a hose that compacts tightly to surfaces. Dull said the redesign eliminates eddies, raises efficiency, and reduces risks to juvenile salmon. 9 million project to rehabilitate two transformers began in July 2025.

The work replaces seals, low side bushings, protective devices, and conservator bladders. Brandon Bouwman, Libby Dam electrical engineer, said a large transformer typically provides 50 years of service and that the current rehabilitation extends that life without full replacement. Libby Dam opened in 1975, and this is the first transformer upgrade since then.

Robert Reeves, Libby Dam electrical engineer, described the transformer as the link that raises generator voltage for long-distance transmission. 6 million project that replaces four five-blade turbines installed in 1957 with new seven-blade units. Barkley Dam is receiving a similar upgrade at approximately $80 million, swapping its four five-blade turbines for six-blade models.

Christopher Stoltz, project manager in the USACE Nashville District, said engineers take units fully offline during upgrades and balance daily energy demand across the system. The Nashville District operates nine hydroelectric dams in the Cumberland River Basin.

U.S. Army Corps of Engineers, compared the dams to engines whose fuel is falling water. U.S. hydroelectric dam, built in Grand Rapids, Michigan, in 1880, powered 16 brush-arc lamps at the Wolverine Chair Factory.

Many USACE dams are over 50 years old. Stoltz noted that energy demand is increasing and will be greater tomorrow.