The Wisconsin Department of Natural Resources is out for comment until Oct. 25 on various air permit changes covering the co-located Alma and J.P. Madgett power plants of Dairyland Power Cooperative, with those changes in part covering the retirements of five coal units at Alma.
The Alma/Madgett site is located along the eastern bank of the Mississippi River on the southern end of the city of Alma, Wisconsin. Historically, the Alma site consisted of six pulverized coal-fired boilers located in two separate buildings. Alma Boilers 1 through 5 were located in a building located on the north end of the site. Each of these boilers have been retired from operation. The J.P. Madgett boiler is located in a building located in the middle of the site. The coal for the J.P. Madgett boiler B25 is delivered by rail.
A DNR permit document covering this current action notes that:
- the department in 2012 received a permit revision application indicating that boilers B20 (Alma 1), B21 (Alma 2), and B22 (Alma 3) had been retired from service on March 1, 2012; and
- the department received a permit revision application in December 2014 indicating that boilers B23 (Alma 4) and B24 (Alma 5) had been retired from service on Sept. 11, 2014, and Oct. 27, 2014, respectively.
A construction permit was issued in 2013 authorizing the installation of pollution control equipment to control emissions from the John P. Madgett (JPM) (Boiler B25), Alma 4 (A4) (Boiler B23), and Alma 5 (A5) (Boiler B24) coal-fired boilers. The Alma 4 and Alma 5 boilers have been retired and the projects authorized for these boilers will not be installed and the associated conditions from this permit for these boilers will not be incorporated into the renewed operation permit.
The pollution control equipment on the surviving, 400-MW Madgett unit (B25) includes a dry sorbent injection system (DSI), an activated carbon injection system (ACI), and a selective catalytic reduction system (SCR). The DSI system reduces sulfur dioxide (SO2) emissions and it is expected that DSI, in conjunction with the fabric filter baghouse will also reduce the emissions of acid aerosols and toxic metals from the boiler stacks. The ACI system reduces mercury (Hg) emissions and the SCR system reduces nitrogen oxide (NOx) emissions.