Environmental Equipment Investments
Since 2007, Dairyland Power Cooperative has invested nearly $300 million for state-of-the-art air emissions control equipment and other environmental investments at its Genoa Station #3 (G-3) and John P. Madgett (JPM) coal-fired power plants. G-3 is located in Genoa, Wis.; JPM is located in Alma, Wis. The air emissions control equipment has resulted in a significant reduction in emissions of sulfur dioxide, nitrogen oxides, mercury and particulate matter.
- In December 2018, a three-year project concluded, which converted the bottom ash transport process at Dairyland's Alma Site to a closed-loop system. The system utilizes leachate from Dairyland’s Alma Off-Site (AOS) disposal area as make-up water to the system, which transports bottom ash from the John P. Madgett (JPM) boiler to the ash dewatering system. It also allows the ash processing system at the Baghouse and Precipitator Silos to utilize bottom ash water instead of water from other sources. Due to normal evaporation, it is estimated up to 25,000 gallons of water are required daily to maintain normal operation. The new system significantly reduces the amount of groundwater required to operate the boiler bottom ash system.
- In 2007, “baghouses” were installed to remove particulate matter from the exhaust gas stream at both the G-3 and JPM power plants, and have resulted in major reductions in particulate matter. The baghouses are in addition to the existing electrostatic precipitators, which capture particulate matter that is recycled as an additive to concrete.
- A Semi-Dry Flue Gas Desulfurization system or “scrubber” is in operation at the G-3 plant. This technology is a sorbent injection process, which sprays a lime slurry into chambers between the boiler and fabric filter baghouse, to remove sulfur dioxide and other acid gases. The “scrubber” process also cools the flue gas, thereby drying the reagent so it can be collected in the baghouse.
- Construction was completed in 2016 for a Selective Non-Catalytic Reduction (SNCR) system and an Activated Carbon Injection (ACI) system at G-3. These technologies reduce nitrogen oxides and mercury emissions. The SNCR system injects liquid urea into the upper levels of the boiler. The urea converts to ammonia and reacts with nitrogen oxide, converting it to nitrogen gas and water vapor. The ACI system injects activated carbon into the flue gas stream. The activated carbon absorbs mercury present in the flue gas and is captured by the baghouse.
- In 2014, construction of a Dry Sorbent Injection “DSI” system and an Activated Carbon Injection “ACI” system was completed. The DSI system injects sodium bicarbonate (SBC) into the flue gas stream. The SBC reacts with sulfur dioxide and other acid gases, which are then captured by the baghouse. Between them, the DSI and ACI systems reduce sulfur dioxide and mercury emissions.
- A Selective Catalytic Reduction (SCR) system at JPM has been operational since April 2016 (see graphic at right). This system uses an aqueous ammonia reagent and catalyst to react with and reduce the amount of nitrogen oxides (NOx) in the flue gas. The ammonia reacts with nitrogen oxide, converting it to nitrogen gas and water vapor, thereby reducing the emissions level of NOx. A major feature of the SCR construction - two large catalyst reaction ducts mounted near the electrostatic precipitators - physically changed the appearance of the JPM power plant. In order to erect the steel for this structure, a large construction crane with a boom extending 300 ft., was used to maneuver the steel assemblies into place.
- In Fall 2020, Dairyland employees developed a way to eliminate the use of steam and water systems with the ammonia injection process. An ammonia direct injection system was installed, using compressed air to atomize the ammonia upon injection into the flue gas stream. This modification reduced the risk of the system freezing up during cold weather operations, which would force the plant offline due to the requirement for air quality control systems to be in service while the plant is operating.
Click here for background information on the JPM power plant.
Click here for background information on the G-3 power plant.