TVA prepares to start smokestack scrubbers

AP News
Posted: Nov 06, 2009 11:57 AM

Smokestack scrubbers will eliminate most of the sulfur emissions from the coal-fired Kingston Fossil Plant, but they will also produce a new waste stream for a site still engaged in a $1 billion cleanup from a massive ash spill.

"It is a tradeoff. In order to clean the air up, you create a landfill," the Tennessee Valley Authority's Ron Nash said Thursday during a tour of Kingston's new $500 million scrubber complex.

"But it is still better to clean the air. We all breathe the air. It is not a choice," said Nash, who heads the scrubber program for all 11 coal-fired power plants operated by TVA, the nation's largest public utility.

Sulfur dioxide is a greenhouse gas produced by burning fossil fuels, like coal.

It contributes to the haze and acid rain that limits mountain vistas and is killing foliage in the nearby Great Smoky Mountains National Park.

It also contributes to respiratory illnesses, particularly in children and the elderly, according to the U.S. Environmental Protection Agency.

Scrubbers remove the sulfur by venting flue gas through a limestone slurry shower. The limestone reacts with the sulfur and creates gypsum _ a stable, nontoxic material that can be recycled.

The first of two scrubbers will go into operation next week at Kingston. The second will start in April.

Together, the scrubbers will eliminate 95 percent of Kingston's sulfur dioxide emissions, Kingston Maintenance Manager Bob Rehberg said. The plant generated around 50,000 tons of sulfur dioxide last year.

All the public will see from Kingston's new 400-foot smokestack will be wispy water vapor.

However, the scrubbers also will be producing some 300,000 to 400,000 tons of gypsum byproduct annually. Gypsum can be used as an additive for wallboard and concrete, but the material is expected to pile up at the plant until the economy improves and the housing industry picks up, creating a demand for gypsum.

TVA has permits to let the gypsum landfill cover 50 acres up to 200 feet high. But Nash said those plans have been vastly scaled down since TVA commited $2 billion to convert all coal operations from wet storage to dry storage in the aftermath of the Kingston coal ash spill last December.

He said Kingston's scrubbers will get an additional $25 million "dewatering facility" in about two years that will further dry and wash the gypsum for resale. It could be a model for other TVA plants.

TVA has spent around $6 billion since the late 1970s reducing emissions of sulfur dioxide, particulates and smog-forming nitrogen oxide. Still, TVA is a facing a deadline to do more.

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A federal judge has ruled in a lawsuit brought by the state of North Carolina that TVA must significantly reduce pollution from four coal-fired power plants affecting North Carolina's air quality by December 2013.

The nine-boiler, 1,700-megawatt Kingston plant is one of the four cited plants and will meet the deadline. So will the Bull Run plant near Knoxville, which put its scrubber online in 2008.

Meanwhile, the Widows Creek plant in north Alabama has scrubbers, but needs other controls and suffered a leak in its older-design gypsum facility shortly after the Kingston ash spill.

And TVA has concluded there isn't enough time to install pollution controls for the fourth plant _ John Sevier in northeastern Tennessee. While the plant's fate is undecided, TVA is building an $820 million gas-fired power plant on the site to provide cleaner power for that end of TVA's seven-state service territory.

Knoxville-based TVA serves nearly 9 million consumers in Tennessee and parts of Kentucky, Alabama, Mississippi, Georgia, North Carolina and Virginia.