Duke verifies air compliance on Cliffside coal-fired unit

North Carolina Department of Environment and Natural Resources two lawsuits Duke Energy Progress Inc Duke Energy Carolinas LLC coal ash impoundment wastewater discharges violate permits

Duke Energy (NYSE: DUK) announced Wednesday that repeated testing at the new 825-MW Unit 6 at Cliffside Steam Station in North Carolina has shown all emissions are well below the permit limits for full load conditions.

The most common hazardous air pollutant from a coal plant is hydrogen chloride (HCl), and Cliffside 6 is emitting less than a quarter of its permitted amount, according to Duke. That number is equivalent to less than 2.5 tons of HCl emitted annually and marks a greater than 99.913 percent removal rate.

The unit also removes 99 percent of sulfur dioxide, 90 percent of nitrogen oxides and 90 percent of mercury. According to Duke, the performance of the unit shows it is well-positioned to demonstrate compliance with the federal mercury rule that will be in effect by April 2014, requiring a limit of 0.013 lb/GW-hr of mercury emissions. The data released by Duke shows the unit emitting between 0.001 to 0.008 lb/GW-hr of mercury.

Plant Manager Rick Roper said the unit’s air permit is “one of the most restrictive in the country, and it’s performing very well.

The plant began commercial operation last December and has allowed Duke to retire older, less-efficient coal plants. That includes retiring seven of the company’s 14 in North Carolina by the end of the year.

Duke stated it is planning to retire 6,300 MW of coal capacity in the coming years, which represents 25 percent of its coal-fired power generation fleet.

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