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Columbia Energy Center AQC System Retrofit

An air quality control system retrofit on both units at the 1,023-megawatt Columbia Energy Center enables Alliant Energy to meet environmental standards for future generations.

Columbia Energy Center AQC System Retrofit

We helped Alliant Energy’s Wisconsin Utility create a healthier environment with an air quality control retrofit for Wisconsin Power and Light. We performed construction on both units of the 1,023-megawatt Columbia Energy Center. The engineering, procurement and construction (EPC) project included the erection of a flue gas desulfurization system and pulse Jet Fabric Filter for each unit. This resulted in decreased sulfur and mercury emissions by more than 90 percent.


Construction on the project was performed through the use of select civil and mechanical subcontractors and with a JV partner for the electrical construction. The new Air Quality Control System (AQCS) facilities feature a new Semi-Dry Flue Gas Desulfurization System and a new Pulse Jet Fabric Filter for each unit. The existing Activated Carbon Injection System was extended to serve both units. Common equipment erected to support the new AQCS facilities for both units included a reagent preparation system, lime storage silo, lime storage day bins, ash handling and conveying system, truck-based lime delivery station, and ancillary equipment to support the overall process.

The new AQCS facilities were constructed in an open area to the rear of the existing chimneys. Newly erected ductwork tied into the existing flue gas ductwork before the existing chimneys, then routed the flue gas through the new AQCS equipment and then back to the existing chimneys where it was exhausted. New induced draft booster fans were installed to overcome the additional flue gas pressure drop resulting from the new configuration.