Cheswick power plant gets OK to run during repairs

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GenOn Energy Inc., the new name of the company that owns the Cheswick coal-fired power plant, has been granted permission to temporarily operate that facility while its new pollution controls are turned off.

According to a Dec. 7 GenOn letter to the Allegheny County Health Department, the emissions control equipment installed this summer at the 637-megawatt power plant is already so severely corroded it can't be used.

The plant has been shut down since October, when during scheduled maintenance, the company discovered the trouble with the equipment.

In response to a power company request, the Health Department agreed last Thursday to allow GenOn to start up the power plant without the flue gas desulfurization equipment, commonly called a "scrubber," and emit pollutants at pre-scrubber levels. That approval to operate expires March 31.

The approval, which was not announced by the Health Department, will allow the Houston, Texas,-based power company to emit sulfur dioxides, nitrogen oxides, airborne particles and hazardous air pollutants at levels allowed prior to installation of the scrubber.

GenOn's Cheswick coal-fired power plant, which, despite its name, is located in Springdale Borough, has been operating since 1970. In 2008 it emitted 30,300 tons of sulfur dioxide, 4,100 tons of nitrogen oxides, more than 400 tons of airborne particulates, and another 400 tons of gases that turn into particles as they cool, according to the Allegheny County Health Department's Emissions Inventory Report.

The smokestack scrubber, which began operating in June, was supposed to reduce emissions of sulfur dioxides, hydrochloric acid and airborne particles by up to 98 percent, according to the Allegheny County Health Department.

GenOn said it discovered the problem when it shut down the Cheswick plant in mid-October for scheduled maintenance and reviewed operation of the scrubber system because of reports that the equipment had corrosion problems at other power plants.

The corrosion problem in the scrubber vessel has occurred at as many as 70 other power plants across the country and appears to be caused by the type of metal alloy used for that part of the equipment. GenOn will install protective liners and coatings to correct the problem and expects to have those repairs finished by early March.

The plant will stay idled while new ductwork is installed to route exhaust gases from the main boiler, bypassing the scrubber and routing emissions to the plant's old, taller smokestack.

The company, which was formed earlier this month by the merger of RRI Energy and Mirant, expects operation of the power plant will resume sometime in January when that ductwork is in place and after it installs continuous emissions monitoring equipment and other monitors to measure sulfur dioxide, nitrogen oxides and carbon dioxide emissions.

The power plant is also required by the Health Department's authorization letter to minimize emissions by using coal with lower sulfur content.

"If it's any consolation, the plant's emissions, while unscrubbed, will be dispersed from the old, higher stack, 750 feet in the air," said Guillermo Cole, a Health Department spokesman. "That should minimize the local fallout. Naturally, with the scrubbers operating, it's a better scenario both locally and downwind."

GenOn declined comment but referred reporter's questions to background information contained in the six-page letter sent to the Health Department by Keith Schmidt, GenOn environmental policy director.

The Cheswick power plant operates primarily as an "electrical load following" unit, GenOn said in its letter to the Health Department, meaning that its operation would provide electrical grid stability during high-usage winter months.


Don Hopey: dhopey@post-gazette.com or 412-263-1983.


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