from the Raleigh News & Observer - published: Dec 08, 2005
Scrubber Freshens Smokestack
Progress Energy cuts sulphur dioxide emissions as it begins to comply with state clean-air law.
Article by Wade Rawlins, Staff Writer
From the Arden community south of Asheville, the white cloud belching from the giant smokestack on Progress Energy's old coal-fired power plant looks to all appearances like pollution.
But since building an enormous $82 million scrubber that was dedicated Wednesday, the plant is mainly spewing water vapor. The scrubber removes the most of the sulphur dioxide, a harmful pollutant that contributes to respiratory problems in children and the elderly, acid rain and the white haze that shrouds the mountains.
The scrubber is the first of more than a dozen similar projects planned statewide, and its installation represents the fruits of the state's Clean Smokestacks Act.
Passed in 2002, the law requires power companies to make significant reductions over the next decade in harmful emissions of sulfur dioxide and nitrogen oxide, which contribute to haze, acid rain, fine soot and the formation of greenhouse gases that scientists link to global climate change.
Progress Energy plans to build scrubbers at five of its seven coal-fired power plants. The first of four scrubbers planned at the Roxboro plant, north of Durham, is scheduled to start working in 2007.
Meanwhile, Duke Power plans to add scrubbers at four of its power plants and has two under construction. The first one will start operating at its Marshall plant in Catawba County next year.
"It's an important milestone in North Carolina," said Bob McGehee, chairman and chief executive officer of Raleigh-based Progress Energy during a brief dedication ceremony for the scrubber. "People all the time call me from other states asking how we got this to happen."
The state's emissions law requires reductions on a faster schedule than federal rules passed earlier this year. And compliance isn't cheap. North Carolina power companies estimate that meeting the state's Clean Smokestacks Act costs about $2 billion. The utilities are passing much of the cost on to residents, who are paying through their electric bills.
To win support for the environmental legislation, state leaders worked out a compromise with the utilities. Instead of lowering rates as they pay off debt, the utilities were allowed to freeze rates at the 2002 level, using the proceeds to help pay for the pollution reduction technology.
"We are all paying for cleaner air," said Michael Shore, an air expert with N.C. Environmental Defense, an advocacy group.
In addition to the scrubbers, the utilities are installing separate equipment to reduce nitrogen oxide, a main cause of ozone, which is a greenhouse gas that causes respiratory problems.
When all the technologies are installed, the Asheville plant will reduce sulfur dioxide emissions and nitrogen oxide emissions by more than 90 percent. Statewide, the law requires a 77 percent cut in nitrogen oxide by 2009 and a 73 percent cut in sulfur dioxide by 2013.
For residents living near the plant, the change has been immediate. Since the scrubber went into use last month, Julia Quillinan has noticed a dramatic decline in the odor near her home. She can see the plant from her front yard, and said she has grown accustomed to its sulphur smell, which is much like rotten eggs.
"I know it doesn't smell in the mornings," said Quillinan, 35, a homemaker. "In mornings, it used to be bad. It's really nice now."
Sulfur dioxide is perhaps most visible and problematic in the mountains, where it contributes to haze that can ruin the scenic views residents prize and tourists drive hundreds of miles to see.
"When our children and grandchildren open the doors to their homes, they'll be able to see the beautiful mountains for miles away," said Nathan Ramsey, chairman of the Buncombe County Board of commissioners.
The Asheville power plant produces electricity for approximately 320,000 homes, along with most of the air pollution in Buncombe County.
"They are by far our number one polluter," said David Brigman, interim director of the Western North Carolina Regional Air Quality Agency, a local city-county agency.
Sulfur dioxide is formed when fuels such as coal and oil are burned. The scrubber removes sulfur from the hot exhaust produced from burning coal by showering it with a mix of water and finely crushed limestone. The sulfur dioxide in the flue gas causes a chemical reaction that produces gypsum.
When both scrubbers are running at this plant next summer, they will reduce emissions of sulfur dioxide by 93 percent, Progress Energy projects.
"It's an extremely large reduction," Brigman said. "That is a major improvement for us."
Building the scrubbers took more than two years.
"You're basically almost doubling the size of the plant to put in the scrubber," said John Moreci, manager of engineering projects for Progress Energy. "You're basically putting a chemical plant on the back of a power plant."
A byproduct of the process -- besides cleaner air -- is synthetic gypsum, a fine sandy-colored powder that can be used to make wallboard and concrete. The plant will produce about 80 tons of synthetic gypsum a day.
Progress Energy has an agreement with U.S. Gypsum Co., a manufacturer and marketer of speciality building products, to market the gypsum to wallboard manufacturers. Progress hopes to sell it to avoid the expense of putting it in a landfill.
Staff writer Wade Rawlins can be reached at 829-4528 or email@example.com