Duke seeks exemption for Lee Unit 3 coal-to-gas conversion

Duke Energy Carolinas applied Nov. 22 at the South Carolina Public Service Commission for approval of a coal-to-gas conversion project at Unit 3 of the Lee plant without having to go through a full certificate proceeding.

The Lee plant is located in Anderson County, S.C. The plan is retire Units 1 and 2 (100 MW net apiece) at Lee in April 2015, and to convert at that point Lee Unit 3 (170 MW net) to firing natural gas. This is the company’s only coal-fired power plant in South Carolina.

In the Nov. 22 application, Duke Energy Carolinas argued that the Unit 3 conversion is a replacement of an existing facility with a like facility, not the construction of a new one, so it qualifies for an exemption from full review for a Certificate of Environmental Compatibility and Public Convenience and Necessity. It noted that its 2012 and 2013 integrated resource plans modeled this unit as a gas resource available for 2015 peak load demand operation.

Lee Unit 3, after the conversion, should retain its current 170 MW rating and not have to take any thermal derates due to the recent addition of new cooling towers at the site. Numerous pieces of existing equipment will be re-used, including the boiler, boiler fans and turbine generator. Additions would include new natural gas burners.

The plan by Duke Energy Carolinas to add a 750-MW, gas-fired combined-cycle plant at its existing Lee site is part of a broader plan that is in part needed to make up for the shutdown of coal-fired capacity on the system. This Duke Energy (NYSE: DUK) subsidiary filed Oct. 25 at the South Carolina commission for a Certificate of Environmental Compatibility and Public Convenience and Necessity on the gas project.

Writing supporting testimony was Janice Hager, Vice President, Integrated Resource Planning and Analytics for Duke Energy Business Services LLC, the service company subsidiary of Duke Energy.

Hager noted the completion at the end of 2013 of the coal-fired Cliffside Unit 6 (825 MW) and the 620-MW Dan River Combined Cycle gas facility, and the recent retirements of the coal-fired Riverbend Units 4-7 (454 MW) and Buck Units 5-6 (256 MW). Then there are the planned Lee Units 1-2 retirements and the Lee Unit 3 conversion.

The retirement of these units, as well as those already retired, is driven by the requirements of air permits for the company’s new coal and combined cycle units at Cliffside, Buck and Dan River, as well as the North Carolina Utilities Commission approval order on Cliffside Unit 6, and expected and known environmental regulations such as the federal Mercury and Air Toxics Standards. “It is the combination of unit retirements and load growth that is driving the 2017 need that the Lee Combined Cycle Project will satisfy,” Hager wrote.

The coal-fired Buck Steam Station Units 3 and 4 were retired in May 2011. The Cliffside Units 1-4 and Dan River Units 1-2 coal facilities were retired in October 2011 and April 2012, respectively, in advance of the initial testing of new generation at those locations. The remaining un-scrubbed coal units at Buck and Riverbend were retired in April 2013, nearly two years earlier than previously planned.

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.