Hydropower and the Corps

The U.S. Army Corps of Engineers is the largest operator of hydroelectric power plants in the U.S., and one of the largest in the world. The 75 Corps plants have a total installed capacity of 20,474 megawatts and produce nearly 100 billion kilowatt-hours a year. Nearly a third of the nation's total hydropower output, it's enough energy to serve about ten million households, or roughly ten cities the size of Seattle.

Corps hydropower plants play a key role in the economy by offering an affordable power source, which helps keep overall energy prices down. Because they don't use fossil fuels Corps hydropower plants also are better for the environment than other sources of electrical power. Without hydropower, the U.S. would have to burn much more coal, oil, and natural gas every year. The increasing availability of hydropower also helps reduce America's dependence on other nations for fuel.

The Corps collaborates on its hydropower efforts with the Department of Energy and a variety of other federal, regional and state agencies and private companies. The Corps is in the process of upgrading many of its facilities to increase efficiency and reliability.

Hydropower at Albeni Falls

Hydropower converts the energy of flowing water into electricity. The amount of electricity generated is determined by the volume of water and the amount of "head" (the height from the turbines in the powerplant   to the water surface) created by the  dam. The greater the flow and head, the more electricity is produced.

Albeni Falls Dam holds back the  Pend Oreille River and can produce power with a head of eight to 33 feet. Intake gates allow water to flow into the dam the turbines inside the powerhouse. As the water falls through a penstock it rotates a  turbine, spinning a steel shaft that turns the generator's rotor. Large electromagnets are located around  the outside of the wheel-like rotor frame. As the rotor turns, the electromagnets establish an alternating magnetic field that penetrates the stationary copper conductors in the coils of the generator stator. As the individual copper conductors in the coils are subjected to the alternating magnetic field, electrical energy is produced. The rotor has the magnetic poles, which generate electricity when they spin around the copper windings in  the generator's stationary stator.

The powerhouse is capable of producing 42,000 kilowatts of electricity when generating at full capacity. Initially it is carried to the Bonneville Power Administration (BPA) switchyard near the dam. BPA distributes and sells electricity produced at federal power plants in the Northwest to public and private utilities. Power generated at Albeni Falls is transmitted through the BPA grid to many regional locations, not only Idaho but also Washington, Oregon, Montana, California, Wyoming, Utah and Nevada.


Hydropower Facts

  • Hydropower is more efficient than any other form of electrical generation.  It is capable of converting 90 percent of available energy into electricity. The best fossil fuel plant is only about 50 percent efficient.
  • Hydropower is a low cost alternative. On average, hydropower production costs one-third that of nuclear or fossil fuel production.
  • Hydropower can easily respond to power needs. Hydropower dams have the ability to be turned on and off quickly. Other forms of electrical production, such as a coal power, require a great deal of time to start or stop producing electricity.
  • Hydropower is a clean, reusable source of electricity. It produces no emissions and its fuel (water) can be used at each downstream dam.
  • Hydropower is domestic. Our supply of water is continually replenished through rain and snowmelt. We are not dependent upon foreign fuel supplies and their possible interruption.