Electric power in the Tennessee Valley is one product of TVA’s Multiple Resource Development Program, produced economically and sold at low rates so it can be widely used as a tool of economic growth, while vital defense industries also depend on TVA power. Although TVA always owned steam plants, for years it generated most of its electricity at dams on the Tennessee River System, but rapid growth in civilian and defense requirements far exceeded the river’s power capabilities. To meet its legal responsibility to furnish power to an area of 80,000 square miles in parts of seven states, TVA built large, efficient steam-electric generating stations. Placed in operation in 1966, the Bull Run Plant had an initial capacity of 950,000 kilowatts in one unit. Its furnaces burn over two million tons of coal a year, most of it from mines in Southeastern Kentucky, and more than 400,000 gallons of cooling water is pumped through the plant each minute. Coal arrives by train across the valley, is weighed and dumped automatically, then carried by belt conveyors to storage and coal bunkers, pulverized, and blown into furnaces where it burns on contact with preheated air. Furnace temperatures reach about 2,750 degrees Fahrenheit, generating steam from pure water in continuous tubing lining the furnaces at a pressure of 3,500 pounds per square inch. This steam drives the turbine, which turns the generator rotor to make electricity; switchyard equipment transforms the power to high voltage for transmission to consuming centers. After leaving the turbine, spent steam flows to condensers, where it is turned back into water and reused, while gases from the burning coal pass through an 800-foot chimney after fly ash is removed by electrostatic precipitators.