One of two turbines, May 1964.
Thomas E. Petermann Collection (S-2005-89-155)

A scroll case under construction, before its connection to the penstock, Summer 1964.
Thomas E. Petermann Collection (S-2005-89-141)

To generate electricity, an intake gate on the lake side of the dam is opened. Water flows into the penstock, a long tube that travels downward and ends in a spiral scroll case. The mass of the water and the acceleration it achieves by falling and circling pushes against the turbine buckets, forcing the turbine to spin. A generator connected to the turbine shaft creates electricity which is sent to transformers in the switchyard and converted to a usable voltage. The power is delivered over high-voltage lines to an electric substation.

Beaver Dam’s powerhouse contains a small, in-house generator for its own use and two large generators, each of which can produce 56,000 kilowatts of electricity, enough for 25,000 homes. The decision to generate power is made by remote radio control from Table Rock Dam. Hydroelectric power from Beaver Dam is sold through the Southwest Power Administration, an agency of the U.S. Department of Energy, to electric companies in Arkansas, Kansas, Louisiana, Missouri, Oklahoma, and Texas.