Marshall Combustion Turbine Plant
Marshall Combustion Turbine Plant near Calvert City, Ky., in Kentucky farm country. It is one of four TVA facilities that generate power with combustion turbines alone and the only such TVA facility in Kentucky. TVA also operates combustion turbines at four of its coal-fired power plants -- Allen, Colbert, Gallatin and Johnsonville -- and at one non-coal facility (Lagoon Creek) that also has combined-cycle units.
Combustion turbines can run on natural gas or low-sulfur fuel oil and can start quickly to meet the demand during peak operating periods. The units at Marshall can reach full power in just 12 minutes. The plant was already interconnected to the TVA transmission system when it was acquired by TVA.
Combustion turbines operate on the same general principle as a jet engine. Air enters at the front of the unit and is compressed, mixed with natural gas or oil, and ignited. The hot gas then expands through turbine blades to turn the generator and produce electricity.
State-of-the-art emission controls and noise management make the Marshall units more environmentally friendly than older types. When running on natural gas, nitrogen-oxide emissions from Marshall are 10 percent less than from combustion turbines built 30 years ago; when burning oil, Marshall's emissions are 20 percent less than from older units.