Internal Combustion Turbines
SCE&G operates sixteen "simple-cycle" combustion turbines at various sites across the state with a capacity of approximately 350 megawatts. In addition, two existing coal-fired furnaces at Urquhart Station were removed from service in 2002 and replaced with new combustion turbines to use natural gas. This "combined cycle" internal combustion turbine process provides an additional 450 megawatts of capacity. In addition, the third coal-fired furnace at Urquhart was converted to burn natural gas, making the plant completely fueled by natural gas.

Combined-cycle technology was also employed at the Jasper Generating Plant, which was placed in service in 2004.  Jasper uses three combustion turbines (with associated heat recovery steam generators) to feed one large steam turbine-generator, providing an additional 870 megawatts of electric capacity.

Facts About Combustion Turbine Plants

  • Combustion turbine plants use technology similar to a jet engine.
  • Natural gas is the primary fuel, but many units can operate on #2 fuel oil as a backup.
  • Although they utilize jet engine technology, combustion turbine plants are very quiet by comparison.
  • Natural gas is an environmentally friendly fuel source that produces very little emissions.
  • In a simple-cycle plant, the combustion of natural gas is the only source of electric generation. A combined-cycle plant utilizes the exhaust heat from multiple simple-cycle units to produce steam that, in turn, powers another turbine and generator. This means more electricity is produced without extra fuel costs.

How A Combustion Turbine Plant Works

  • The combustion of natural gas, combined with compressed air, forces the turbine blades to spin.
  • The spinning turbine is attached to the generator, which produces electricity.
  • In a simple-cycle plant, exhaust heat is emitted through the stack.
  • In a combined-cycle plant, exhaust heat from multiple simple-cycle plants is fed through a heat recovery steam generator (HRSG).
  • The exhaust heat is used to turn water to steam, turning a turbine that is attached to a generator that produces electricity.
  • Steam is cooled in a condenser by water from a nearby river or lake. The cooled steam, now water, returns to the HRSG and the cycle is repeated.

SCE&G Internal Combustion Turbine Plants
Plant Capacity Location
Urquhart Station         650 MW Beech Island, SC
Jasper Generating Plant  875 MW Jasper County, SC

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