Cliffside Steam Station
- Retirement: 2011 (Units 1 – 4)
- Capacity: 1,387 megawatts (MW)
- Location: Cleveland and Rutherford counties, N.C.
- Commercial operation: 1940
Construction for Cliffside’s first unit took a year and a half to complete. That was back in 1939, when power sales in the area had increased 60 percent in five years. Construction of the plant influenced the town’s framework as families moved into the area to build and manage the plant. That first 38-MW unit, along with units 2, 3 and 4 – a total of 198 MW – were retired on October 1, 2011.
Located one-half mile from the original four units is unit 5 in Rutherford County, N.C. In an effort to reduce emissions since its first commercial year in 1972, two upgrades were added to the unit:
- 2002 – A selective catalytic reduction (SCR) system that reduced nitrogen oxide emissions by approximately 80 percent.
- 2010 – A flue gas desulfurization system (scrubber) that reduced sulfur dioxide emissions by approximately 95 percent.
However, it’s the commercial operation of unit 6 on Dec. 30, 2012, that culminated the modernization project at the Cliffside campus. More than four years of construction resulted in a revolutionary clean-coal unit that can generate up to 825 MW – enough to power 660,000 average-sized homes.
The plant uses the most effective air emission controls available. A combination of air quality controls removes:
- 99 percent of sulfur dioxide (SO2)
- 90 percent of nitrogen oxides
- 90 percent of mercury.
In addition, unit 6 is designed to reuse and recycle.
- The cooling tower blowdown is used as makeup for the wet scrubber.
- The wet scrubber purge stream is used as makeup for the dry scrubber.
- A byproduct of the wet scrubber is synthetic gypsum, which is recycled to manufacture wallboard and cement.
With the retirements and upgrades, the Cliffside site generates more than twice the electricity, with 80 percent less sulfur dioxide and half the nitrogen oxides and mercury, than it did previously, and thermal impacts to the Broad River have been eliminated.