The Wisconsin Department of Natural Resources is taking comment until Sept. 14 on a draft permit allowing Wisconsin Electric Power d/b/a We Energies-Valley Station to convert four coal-fired boilers at the Valley plant to fire natural gas.
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 capacity of about 280 MW and is the sole source of steam for the Downtown Milwaukee Steam System. The facility has two generating units of about 140 MW apiece.. Steam for each unit is provided by two boilers (Generating 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 Valley Power Plant, which is located in Milwaukee County, occupies about 22 acres of land between the south Menomonee Canal and the Menomonee River.
The proposed project is to convert these four coal-fired boilers to natural gas-fired boilers. To accomplish this, the following changes will be made:
- 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 (FGR) 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 (DCS).
As the project proceeds, it is possible that other activities or physical changes may be required that are not identified above, the DNR noted.
A Wisconsin Energy‘s (NYSE: WEC) Wisconsin Electric Power subsidiary has also filed an application with the Wisconsin Public Service Commission to implement the much-discussed conversion of the Valley power plant in Milwaukee from coal to natural gas. The utility filed its eight-page application with the PSC April 26. Design, engineering and procurement actually started in the summer of 2012. The company hopes to have the entire project completed by the fourth quarter of 2015.
WEPCO envisions a total gross project cost estimated at $79.8m. The utility said the natural gas conversion plan is the “least cost option.” Installing the necessary environmental controls to keep Valley as a coal-fired facility would be $540m more costly than the preferred natural gas conversion, WEPCO said.
“In the past, absent environmental drivers, it has been more economical to retain Valley as a coal fired facility. As a result of the shift in the economics of coal and gas, it is economic to convert Valley to natural gas at this time,” the Wisconsin Energy subsidiary said.