Wisconsin DNR seeks comment on Valley coal-to-gas conversion permit

The Wisconsin Department of Natural Resources is taking public comment until Nov. 10 on its preliminary determination that an air permit should be issued for Wisconsin Electric Power’s planned coal-to-gas switch of the Valley plant in Milwaukee.

Wisconsin Electric Power d/b/a We Energies-Valley Station filed with the DNR a permit application, including plans and specifications for modification of four coal-fired boilers to natural gas-fired boilers. The DNR has made a preliminary determination that the application meets state and federal air pollution control requirements and that the permit should be approved.

Valley is a cogeneration facility that has an electric generating capacity of approximately 280 MW and is the sole source of steam for the Downtown Milwaukee Steam System. The facility has two electric generating units. Steam for each unit is provided by two boilers (Unit 1 is served by Boilers B21 and B22; Generating Unit 2 is served by Boilers B23 and B24). These four identical Riley dry-bottom wall-fired boilers are currently fired by coal.

The proposed project is to convert these four coal-fired boilers to natural gas-fired boilers. To accomplish this, the following changes will be done:

  • Removal of coal burners and associated coal piping from all four existing boilers;
  • De-energize, decommission and layup retired coal and ash systems including coal conveyors, coal silos, coal mills, coal feeders, bottom ash removal system, and flyash removal system;
  • Installation of new gas burners in each of the four boilers;
  • Installation of a natural gas header and associated valves to supply fuel to the new gas burners;
  • Installation of new flue gas recirculation fans and associated ductwork and electrical for use in the control of NOx emissions from the boilers. One fan will be installed per boiler for a total of four fans;
  • Seal boiler where existing burners, soot blowers and bottom seal equipment is being removed;
  • Installation of boiler let down valves to reliably support steam supply to the District Heating System under single STG operation; and
  • Update control system to integrate new equipment into plant distributed control system.

WEPCO plans to complete the conversion of Unit 1 in 2014 and the conversion of Unit 2 in 2015, so 2014 would be the last full year of coal operation for one or both of these units. The utility said in an Oct. 8 report filed at the Wisconsin Public Service Commission (PSC) that Valley Unit 1 is projected to burn 117,627 tons of coal in 2014, and that Valley Unit 2 is projected to burn 268,352 tons.

Staff at the PSC on Sept. 26 filed an environmental assessment review of this conversion, which WEPCO applied for in April. Wisconsin Gas LLC would construct additional natural gas facilities to service the plant as part of the conversion. WEPCO is a unit of Wisconsin Energy (NYSE: WEC).

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.