Southaven Combined-Cycle Plant

TVA owns the Southaven Combined-Cycle Combustion Turbine Plant, located near Desoto County, Mississippi.

Efficient power production to help meet TVA’s intermediate power needs.

The Southaven Combined-cycle combustion turbines run on natural gas. The generating capacity of the plant is approximately 810 MWs during summer operations.

The units at Southaven can reach full power in one hour, depending on the status of the units.

The units are capable of cycling on and off daily and are used 12-16 hours per day to meet “intermediate” generation needs, or power requirements extending over longer periods of time than “peak” needs, but less that continuous “base load” demand. The site is interconnected to both TVA’s and neighboring transmission systems.

How it works

Combined-cycle technology enables a combustion turbine facility to generate 50% more power output from the same amount of fuel burned in a simple cycle combustion turbine. Fuel is burned in the combustion turbine to produce electricity. The hot exhaust gas heat is captured in a Heat Recover Steam Generator (HRSG) in order to produce steam. This steam is then used to drive a steam turbine to produce an additional 50% output. Additional steam can be produced by separately fired duct burners.

The Southaven Plant has three combustion turbines. Each has one HRSG, which produces steam for one steam turbine.

Duct firing

Additional steam can be produced by duct firing with natural gas in the HRSG. This provides additional power output for the steam turbine. The Southaven plant is capable of an additional 75 MW output due to duct firing.

Emissions

The combustion turbines produce very low NOx and CO emissions. The HRSG then utilizes an SCR (selective catalytic reduction system) to reduce the NOx to a very low level (approximately one-third of a modern simple cycle combustion turbine’s NOx emission using similar technology).

The plant make-up water requirements are provided by waste water from the City of Columbus via a 16 mile pipeline.

The Southaven Plant, which occupies 118 acres in Desoto County, Mississippi, is expected to help TVA meet the rapidly growing peak demands for power and reduce the need to purchase higher-priced power from external sources during periods of high demand.