The Southwestern Power Administration (Southwestern) is an agency of the U.S. Department of Energy. Southwestern's mission was established by Section 5 of the Flood Control Act of 1944. The agency is a power marketing administration responsible for marketing the hydroelectric power produced at 24 United States Army Corps of Engineers multipurpose dams. By law, the power and associated energy are marketed to publicly held entities such as rural electric cooperatives and municipal utilities. Southwestern has over one hundred such "preference" customers which ultimately serve over 8 million end use customers.
Southwestern operates and maintains 1,380 miles of high-voltage transmission lines, 24 substations, and 46 microwave and VHF radio sites from field offices. Around-the-clock power scheduling and dispatching is conducted from the Operations Center. 
Southwestern's rates, by law, are designed to recover the costs of producing the power. These costs include repayment of the dams' initial construction, with interest; repayment of the transmission system construction, with interest; major replacements; and both the Corps of Engineers' and Southwestern's annual operating and maintenance expenses. Annual revenues vary with water conditions, but generally average about US$100 million. Southwestern returns the revenues to the U.S. Treasury, and of that, about US$40 million is applied toward interest and repayment of the Federal investment.