WPL clears testing of activated carbon injection at Nelson Dewey

Wisconsin Power and Light has sought Wisconsin Department of Natural Resources approval to test an activated carbon injection system for mercury control at the coal-fired Nelson Dewey plant.

“The Bureau of Air Management, Department of Natural Resources, received your application on October 31, 2011 requesting an exemption from the requirement to obtain an air pollution control permit to research and test an activated carbon injection system in combination with Clean Coal Solutions CyClean sorbents for controlling mercury emissions in one of the facility’s cyclone boilers,” said a March 16 DNR letter to the company.

“The original request was written as such that only one of the two boilers would be tested,” the letter added. “However, the Department has determined that either boiler could be tested independently of each other. The revision is to allow the second boiler, unit #1, to now be tested as the testing has been completed on unit #2. The proposed test may be exempted from permitting requirements…provided that the testing or research will not present a significant hazard to public health, safety, or welfare or to the environment. The Department has determined that these test burns will not present a significant hazard. Preliminary tests suggest that there actually may be a reduction in overall particulate emissions as the activated carbon sorbent may also collect condensable particulate matter.”

If the testing is successful and WPL decides to continue to use activated carbon in conjunction with Clean Coal Solutions CyClean sorbents, it may need to submit permit application forms for a construction permit to obtain approval to use those materials, the March 16 letter said.

Last November, the DNR sent the utility granting an exemption from the requirement to obtain an air pollution control permit to research and test an activated carbon injection system in combination with the CyClean sorbents for controlling mercury emissions in one of the facility’s cyclone boilers. The department has determined that these test burns will not present a significant hazard.

WPL is a unit of Alliant Energy (NYSE:LNT). Alliant said in its Feb. 27 annual Form 10-K report that Nelson Dewey is a two-unit plant with a total of 208 MW of capacity, with those units brought online in the 1959-1962 period and currently operating at only intermediate load. Other WPL coal units operate at baseload.

In a Feb. 28 filing with the Wisconsin Public Service Commission about coal contracts in place in 2011, most of the information has been redacted. But the filing does show two coal contracts for Nelson Dewey signed in 2005 and 2008, and also a “Skyline test burn” contract signed in March 2011. It isn’t clear whether that is a reference to Arch Coal‘s (NYSE:ACI) Skyline longwall mine in Utah, which produces a low-sulfur coal.

In a Feb. 24 WPL filing with the commission about actual 2011 versus projected 2011 fuel burns, the utility said: “At Nelson Dewey 1, total expenditures for biomass fuel were lower by approximately $3.0m due to a 40,000 ton reduction in the volume of fuel. The reduction in biomass fuel burn was driven by constrained supply combined with a significant runup in prices. The reduced biomass fuel was replaced by relatively lower priced coal and petcoke. The impact on 2011 fuel expenses due to test burning biomass in place of the coal and pet coke blend was an increase of $1.6 million.”

The U.S. Energy Information Administration database shows Nelson Dewey in most months of last year taking petcoke from Koch Carbon and Powder River Basin coal from the Spring Creek mine in Montana of Cloud Peak Energy (NYSE:CLD).

Alliant in the Form 10-K didn’t single out Nelson Dewey in a section on major WPL emissions control projects. There are two other coal facilities mentioned for those major projects.

  • Edgewater Unit 5 – In May 2010, WPL received an order from the Wisconsin Public Service Commission authorizing the installation of a selective catalytic reduction system at Edgewater Unit 5 to reduce NOx emissions at the facility. Construction began in the third quarter of 2010. In addition, WPL’s current compliance plans include installing an SO2 scrubber and baghouse at Edgewater Unit 5 to reduce SO2 and mercury. WPL plans to file an application with the Wisconsin PSC for these projects in 2012. The SCR is due in-service in 2013, with the scrubber and baghouse systems to follow in 2017.
  • Columbia Units 1 and 2 – In February 2011, WPL received approval from the Wisconsin PSC to install scrubbers and baghouses at Columbia Units 1 and 2 to reduce SO2 and mercury emissions. These projects are due online in 2014.
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.