PSCo completes shutdown of two Cherokee coal units, conversion of one

The projected construction schedule to support the Colorado Clean Air-Clean Jobs Act plan included demolition of the coal-fired Cherokee Units 1 and 2 to support construction of a gas-fired 2×1 combined cycle power plant.

The overall destruction/construction project is currently tracking to be complete ahead of the required January 2014 date, said Public Service Co. of Colorado in a semi-annual project update filed March 15 at the Colorado Public Utilities Commission. The company is a unit of Xcel Energy (NYSE: XEL).

In various proceedings, the commission has authorized Public Service to proceed with the completion of specific components of its Clean Air-Clean Jobs Act (CACJA) compliance plan, which the commission approved in a 2010 docket. The commission approved the retirements of Cherokee Unit 2 no later than Dec. 31, 2011, and Cherokee Unit 1 no later than July 1, 2012. Unit 2 was shut down in October 2011 and Unit 1 was shut in April 2012.

Several key activities were completed this reporting period, the company noted. Environmental Demolition Inc. (EDI), the asbestos abatement subcontractor completed the major abatement activities on Unit 2 boiler in October and on Unit 1 boiler in December 2012. Miscellaneous abatement continues in the boiler building. Brandenburg, the demolition contractor, completed demolition of the Unit 2 cooling tower and baghouse in July and Unit 2 precipitator in September 2012. Unit 2 boiler tubes were removed in preparation for the boiler structure removal. Demolition of the Unit 1 cooling tower was completed in May and Unit 1 baghouse was completed in August 2012. Unit 1 boiler tube removal was started in December and continues to date.

During this reporting period Brandenburg also completed demolition of both ash silos, the main and auxiliary warehouse, fire protection pump houses #1 and #2, #1 crusher stackout conveyor, and Units 1 and 2 dry sodium injection equipment.

The utility also filed a semi-annual report with the commission on March 15 about the completed project to convert Cherokee Unit 2 to a synchronous condenser, which provides local grid support. The synchronous condenser went into service on April 14, 2012, and was declared available for “Commercial Operation” on June 1, 2012.

The company had awarded a contract to General Electric to furnish and erect the facility. A second contract was awarded to Guarantee Electrical Contracting for the Balance of Plant. During this reporting period final punchlist activities were completed and Western Electric Coordinating Council (WECC) testing was successfully performed. Final Acceptance was achieved on Sept. 30, 2012. The unit is designed to operate continuously and can be remotely controlled by Xcel Energy’s Transmission Operations for 24-hour VAR control.

Several coal shutdowns, retrofits and gas conversions in the works

Xcel said in its Feb. 22 annual Form 10-K report that PSCo’s plan as of the end of 2012 to institute the CACJA is as follows:

  • Cherokee Units 2 and 1 were shut down in 2011 and 2012, respectively, and Cherokee Unit 3 (365 MW in total) is expected to be shut down by the end of 2016, after a new natural gas combined-cycle unit is built at Cherokee (569 MW);
  • Cherokee Unit 2 was converted to a synchronous condenser;
  • Fuel switch the coal-fired Cherokee Unit 4 (352 MW) to natural gas by 2017, unless a more cost-effective bid is provided to PSCo in response to a request for proposals (RFP) to be issued in Phase 2 of the PSCo Resource Plan in early 2013. If a more cost-effective bid is obtained, then Cherokee Unit 4 would be retired at the end of 2017;
  • Shut down the coal-fired Arapahoe Unit 3 (45 MW) at the end of 2013;
  • Fuel switch the coal-fired Arapahoe Unit 4 (111 MW) at the end of 2013, unless a more cost-effective bid is provided to PSCo in response to the RFP to be issued in Phase 2 of the PSCo Resource Plan in early 2013. If a more cost effective bid is obtained, then Arapahoe Unit 4 would be retired at the end of 2013;
  • Shut down the coal-fired Valmont Unit 5 (186 MW) in 2017;
  • Install selective catalytic reduction (SCR) for controlling NOx and a scrubber for controlling SO2 on the Pawnee coal plant in 2014; and
  • Install SCRs on the coal-fired Hayden Unit 1 in 2015 and Hayden Unit 2 in 2016.

In a third March 15 report, the utiity said the Cherokee site development work for the new 2×1 CC power plant is nearing completion. The new raw water and fire water systems at the existing northwest reservoir are in service. The three raw water ponds at the south end of the plant have been drained and are being remediated and filled in to be used as the site for the new power plant. The company has placed contracts for the combustion turbines, heat recovery steam generators (HRSG) and GSU transformers. The 2×1 CC power plant design-build contract (DBC) was awarded to Kiewit in September 2012. Kiewit is performing detailed engineering and design of the 2×1 CC power plant and will be procuring the balance of equipment and constructing the plant. Construction will start in summer of 2013.

Pawnee air project work at the site is underway

PSCo also reported on the status of the Pawnee emissions controls. Sargent & Lundy has been selected to provide consulting and balance of plant engineering services. Detailed engineering, equipment specifications development, and various engineering studies and evaluations are in progress. Procurement Update Contracts have been awarded for the supply of major equipment systems.

The Pawnee flue gas desulfurization (FGD) systems, and selective catalytic reduction (SCR) systems are being supplied by Babcock & Wilcox (B&W). Detailed engineering is nearing completion and B&W has subcontracts in place for major subsystems such as lime preparation. The new Induced Draft (ID) fans are being supplied by Howden-Variax. Detailed engineering is in progress.

The new waste ash system is being supplied by United Conveyor Corp. Detailed engineering is nearing completion. Erection of the new ash silo is scheduled to begin in May. Modifications to the Fabric Filter Dust Collectors was awarded to Hartman-Walsh. The modifications are about 25% complete.

All balance of plant equipment has been ordered except the distributed control system (DCS) modifications. Site preparation construction was awarded to Garney Construction. Foundation construction was awarded to The Industrial Company (TIC). The general construction contract was awarded to TIC in late December 2012.

Hayden SCR projects in the works

As for the Hayden air projects, a March 15 update said that Sargent & Lundy has been selected to provide consulting and balance of plant engineering services. Several studies of current operating conditions and impacts of the required new equipment have been initiated.

The contract for the SCR equipment was awarded to Hitachi Power Systems America Ltd. Detailed engineering commenced in December 2012, with initial deliveries beginning in March of 2014.

Upgrades to the existing induced draft fans will be required. Unit 1 will require fan tipping and upgraded motors. Unit 2 will require new fans and motors. Requirements for procurement of other equipment, including long lead time electrical equipment and long lead time mechanical equipment are being prepared.

Construction activities for Unit 1 foundations are being planned for late 2013 with erection of SCR equipment beginning in 2014 and completing in 2015. Construction activities for Unit 2 foundations are being planned for late 2013 with erection of SCR equipment beginning in 2015 and completing in 2016.

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.