Magnolia Combined Cycle Gas Plant
The Magnolia plant is a modern, fully permitted facility with a proven operational history. It is TVA’s third wholly owned combined-cycle gas plant and its largest. TVA operates a fourth combined-cycle plant, Caledonia, under a long-term lease agreement. A fifth, John Sevier – also wholly owned – began commercial operation in 2012.
Combined-cycle units are enhanced versions of simple-cycle combustion turbines. They burn natural gas or low-sulfur oil and operate on the same principle as a jet engine. Air entering each unit is compressed, mixed with fuel, and ignited. The hot gas expands through turbine blades that turn generators to produce electricity.
Combined-cycle units generate 50 percent more power than simple-cycle turbines from the same amount of fuel. They do this with a heat recovery steam generator, which uses the exhaust from the first turbine to produce steam that can generate additional electricity from a second turbine.
Combustion turbines and combined-cycle units help provide the extra power TVA sometimes needs during peak demand periods.