Columbia co-owners pursue scrubbers for both coal units

Wisconsin Power and Light got an air construction permit last November from the Wisconsin Department of Natural Resources for new SO2 scrubbing equipment on Units 1 and 2 of the coal-fired Columbia power plant in Columbia County.

The permit said that WPL “is authorized to construct and initially operate a spray dryer absorber and a baghouse for each of Boiler B21 (Unit 1) and Boiler B22 (Unit 2), and two lime silos, and to expand the existing activated carbon injection (ACI) system installed in 2008 on Unit 2 to serve both Units 1 and 2 as described in plans and specifications dated July 29, 2011 through September 25, 2011, and November 4, 2011 in conformity with the conditions herein.”

In a November 2011 document responding to comments from company officials and outside parties on the draft version of this permit, the DNR addressed a Sierra Club complaint that the electricity needed to operate the scrubbers would be a “parasitic load” that might drive up coal usage to compensate and therefore increase CO2 emissions.

The DNR responded: “The permit application material has stated that: ‘The AQCS Project will not affect the capacity of each power boiler. In addition, this project will not result in any additional fuel consumption. WPL has also determined that the boilers will not realize an increased utilization, i.e., the increase in annual operating hours from the project will be zero.’ The applicant has informed the Department that whatever power necessary to operate the spray dryer absorbers and associated equipment may result in that small amount of power not being sent to the power grid. As such no increase in fuel usage is expected.”

WPL is a unit of Alliant Energy (NYSE:LNT), which said in its Feb. 27 annual Form 10-K report that WPL owns 46.2% and is the operator of the two-unit Columbia plant, which has a total capacity of 1,009 MW. In February 2011, WPL received approval from the Public Service Commission of Wisconsin to install scrubbers and baghouses at Columbia Units 1 and 2 to reduce SO2 and mercury emissions, the Form 10-K noted. The scrubbers and baghouses are expected to be in service in 2014.

The scrubbers and baghouses at Columbia Units 1 and 2 are expected to support compliance obligations for current and anticipated air quality regulatory requirements, including the Clean Air Interstate Rule, the Cross-State Air Pollution Rule, the Utility Maximum Achievable Control Technology rule and the Wisconsin state mercury rule, said the Form 10-K. WPL’s portion of the capital expenditures, excluding allowance for funds used during construction, for the scrubbers and baghouses is currently estimated to be between $280m and $310m.

The plant is called the Columbia Energy Center (CEC) in DNR documents. “CEC is a nominal 1,054 MW subbituminous coal fired, electrical power station located near the town of Pardeeville, in Columbia County, Wisconsin,” said one of those documents. “WPL co-owns CEC with Wisconsin Public Service Corporation (WPSC) and Madison Gas and Electric (MGE). WPL is the operator of CEC. The station currently consists of two nominal 527 MW pulverized coal fired boiler/generator sets and associated equipment. … Particulate emissions from the boilers are currently controlled by electrostatic precipitators, which will remain in service.”

Note that the Columbia capacity figures given in the Form 10-K and by the DNR differ slightly, which is common since such figures are often based on differing standards, like nameplate, nominal, net summer dependable, etc.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.