Xcel unit makes progress on new Pawnee coal unit air controls

Public Service Co. of Colorado has selected Sargent & Lundy to provide consulting and balance of plant engineering services, with detailed engineering, equipment specifications development, and various engineering studies and evaluations in progress for new emissions controls on the Pawnee coal plant.

Public Service, a unit of Xcel Energy (NYSE: XEL), filed a Sept. 20 semi-annual progress report with the Colorado Public Utilities Commission on the Pawnee work, which was authorized by the commission as part of the utility’s Clean Air-Clean Jobs Act (CACJA) compliance plan.

Contracts have been awarded for the supply of major equipment systems. There has been no major material departure from reported conceptual design. The flue gas desulphurization (FGD) and selective catalytic reduction (SCR) systems are being supplied by Babcock & Wilcox (B&W). Detailed engineering is in progress and B&W has subcontracts in place for major subsystems such as lime preparation. Delivery of components will begin in the first quarter of 2013. The new Induced Draft (ID) fans are being supplied by Howden-Variax.

Procurement of other equipment including fabric filter dust collectors (FFDC) modifications, long lead electrical equipment, steam coil air heaters, compressed air equipment, pumps, and control valves are in progress, the utility noted.

Proposals for early construction activities including site development and FFDC compartment stiffening have been received and are being evaluated. The proposals for foundation installation are also being evaluated. Development of technical specifications for the General Constructor is in progress with mobilization scheduled for January 2013.

In its application to the commission for approval of this project, Public Service provided a cost estimate for the project of $238.6m in 2010 dollars. Included in this estimate was the cost of the sorbent injection for $2.1m. That portion of the project is complete and its actual costs were only $1.16m. Public Service said it currently has approximately 47% of the total project direct cost under contract. As of June 30, 2012, it had spent $25,322,858 or 10% of the summary cost estimate of $252.045m. Project completion is expected in December 2014.

Incidentally, the Colorado Air Pollution Control Division is seeking public comment until Oct. 11 on draft air permitting for the project. Pawnee Unit 1 is required to meet the regional haze emission limitations by Dec. 31, 2014. Public Service will be installing a lime spray dryer (LSD) to reduce SO2 emissions and SCR to reduce NOX emissions, the division noted.

“Unit 1 is being equipped with a LSD and SCR in order to meet the lower NOX and SO2 Regional Haze limits, hence there will be an overall reduction of NOX and SO2 emissions from this unit,” the division said. “It is not expected that the addition of the LSD and SCR will increase the emissions of any other pollutant, nor is it expected that the addition of the LSD and SCR will increase the utilization of the boiler.”

The Xcel website said that Pawnee is a single-unit, 505-MW plant that gets its coal from the Powder River Basin of Wyoming. U.S. Energy Information Administration data shows deliveries to Pawnee earlier this year from the Eagle Butte mine of Alpha Natural Resources (NYSE: ANR), which was mentioned on the website as a supply source, and also from the Buckskin mine of Kiewit Mining Group

“In spring of 2010, the Colorado legislature passed the Clean Air-Clean Jobs Act, which Xcel Energy supported,” the Xcel website said. “The legislation requires regulated utilities, like Xcel Energy, to work to reduce emissions from coal-fired power plants. As a result, controls to reduce plant reduce emissions of nitrogen oxide and sulfur dioxide at Pawnee will be installed by 2014. Air emissions are controlled at Pawnee Station by a baghouse, which was installed in 1994. A baghouse acts like a giant vacuum cleaner, removing particulate emissions from the flue gas by more than 99 percent. The plant also has fuel blending facilities, dust suppression and collection equipment and low NOx burners to reduce emissions of nitrogen oxides.”

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.