TVA to clean scrubbers that emit air pollutant

TV A to clean scrubbers that emit air pollutant

BY DAVE FLESSNER
BUSINESS EDITOR

The Tennessee Valley Authority is spending more than $1 million a day on pollution controls to reduce some of the main contributors to smog.

But some of the scrubbers and selective catalytic reduction devices installed to cut emissions at TVA's coal-fired power plants generate an unintended pollutant, sulfur trioxide, John Shipp, vice president of environmental policy for TVA, said Friday.

Combined with other chemicals, the sulfur trioxide can create a dark-colored plume from smoke stacks, Mr. Shipp said.

As a result, TVA is facing problems meeting state requirements for the opacity, a measure of discoloration, of the smoke from its plants. TVA directors are scheduled next week to award a contract for up to $120 million to try to fix the problem.

"We've been testing different technologies on a limited basis, but this will be the first major installed system to deal with this problem," Mr. Shipp said.

Over the next 10 years, TVA will contract with Nol-Tec Systems to design, build and test a hydrated lime injection system to cut sulfur trioxide emissions. Injecting lime into the effluent from the burning of coal should cut significantly the amount of sulfur trioxide emitted, officials said.

"This was determined to be the most cost effective and best approach to this problem," TVA spokesman John Moulton said.

The new process first will be tried at major coal plants, including the Cumberland Steam Plant near Nashville this year and Widows Creek Fossil Plant near Stevenson, Ala., next year, he said.

The opacity problem is far less severe than the problems

created by soot and smog from coal plants, according to Stephen Smith of the Southern Alliance for Clean Energy. But Dr. Smith said the cost and complexity of dealing with all of the emissions from coal plants should encourage TVA officials to rethink the agency's approach to extending the life of some of its oldest and dirtiest plants.

"The new air pollution requirements already announced should encourage TVA to rethink whether it wants to continue to make major investments in some of its oldest and smallest coal units," Dr. Smith said.

"We think TVA needs to look at alternatives like coal gasification and clean fuels," he said. "But unfortunately, TVA doesn't have a clear integrated power planning approach that allows the public to review how it is approaching these issues."

Mr. Shipp said that for now TVA has determined that the lowest-cost electricity will continue to come from extending the life of its coal plants even with stricter pollution controls.

TVA officials expect to have spent $5.6 billion by 2010 to cut sulfur and nitrogen oxide emissions by more than 75 percent from the peak levels reached in the 1970s, he said.

"It is costly, and all ratepayers must pay more as a result," TVA Director Bill Baxter said earlier this week.

Beyond the hefty capital costs for scrubbers, low-NOX burners and selective catalytic reduction devices, TVA also is having to spend more than $50 million a year just in chemicals to inject in its coal plants to limit smog producing emissions.

TVA plans to spend $200 million over the next five years to buy anhydrous ammonia needed for its nitrogen oxide-reduction equipment. To operate its coal scrubbers, TVA expects to spend $55 million over the next five years to buy up to 1 million tons of limestone a year.

"It's just another cost of doing business to meet today's air pollution standards," Mr. Shipp said.

TVA directors are scheduled to approve contracts with Cherokee Nitrogen, LaRoche Industries, Terra Industries and the Rogers Group Inc. to buy the pollution-control chemicals.