Lee Steam Station

Duke Energy announced last week that the company plans to excavate a portion of coal ash at the W.S. Lee Steam Station while it continues engineering work on the rest of the site. The announcement was made during a briefing before the Public Service Commission of South Carolina (PSCSC).

The 370-megawatt W.S. Lee Steam Station began operating in 1951 and currently manages ash in two active ash basins, referred to as the primary and secondary basins. The site also has an inactive ash basin constructed in the 1950s, a structural fill and an ash fill.

“Based on the engineering work we’ve conducted at the site, we are opting to pursue a fully lined solution for the ash located in the inactive basin and the ash fill, while we continue evaluating the best closure method for the remaining ash,” said John Elnitsky, senior vice president for Duke Energy ash basin strategy.

The company’s evaluation determined a capping system would not be suitable for the inactive basin and fill area. Constructed many years ago, the inactive basin’s dike walls are steep and would require extensive tree removal and additional work to make that location appropriate for long-term storage.

Duke Energy will evaluate a variety of disposal options, including the feasibility for permitting a landfill on plant property or relocating ash to an off-site landfill or structural fill. All those options will include a double bottom liner, leachate collection, synthetic capping system and groundwater monitoring.

The company continues to perform engineering studies on the two active ash basins and remaining structural fill to inform its recommended closure strategy. The company plans to submit that strategy to the South Carolina Department of Health and Environmental Control by year-end.

The W.S. Lee Steam Station is expected to cease using coal by April 2015. Unit 3 will be converted to a natural gas boiler, and a separate 750-megawatt natural gas combined cycle plant will be constructed at the site to continue meeting customers’ needs in the Upstate.

More information about the company is available at: www.duke-energy.com.