By MARK WILSON Courier & Press http://www.courierpress.com/
Mandatory pollution controls such as the ones that began working this month at the Alcoa-Warrick Power Plant are expected to help the Evansville area meet federally required ozone pollution levels.
Warrick and Vanderburgh counties do not meet the new pollution standards for ozone and fine particulate matter, according to the U.S. Environmental Protection Agency.
The latest pollution controls, installed on the largest of the facility's four power-generating boilers, are a $46 million investment, said Scott Darling, environmental manager at Alcoa Warrick Operations, which produces aluminum.
The controls are part of Alcoa's efforts to comply with new state and federal pollution rules calling for a 65 percent reduction, from 1995 levels, of nitrogen oxide pollution at power plants. The rule includes a 31 percent statewide reduction to be achieved this year.
The pollution control, called a selective catalytic reduction unit, is capable of removing up to 85 percent of the nitrogen oxide (NOx) from the coal-burning generator's emissions. That's on top of a 50 percent nitrogen oxide reduction achieved by the installation in 1998 of another control process called low-NOx burners, said Alcoa spokeswoman Sally Rideout Lambert.
That process works by lowering the temperature of the flame burning the coal, said Dave Parenti, environmental projects manager. But in selective catalytic reduction, a vaporized solution of ammonia and water is injected into the gas emissions created by the burned coal.
"It basically converts the bad nitrogen oxides into good, normal nitrogen and water vapor," Parenti said. He noted that Earth's atmosphere is more than 78 percent nitrogen.
Ozone is formed when nitrogen oxide and other pollution combine in heat and sunshine. Because of this, May 1 to Sept. 30 is often referred to as "ozone season," when the pollution typically reaches its worst levels. It can cause breathing difficulties, damage lung tissue even in healthy adults and aggravate respiratory conditions such as asthma.
Having the selective catalytic reduction units such as those at Alcoa working this ozone season should be a good thing for Tri-State residents from both health and economic perspectives, said Joanne Alexandrovich, who tracks ozone pollution issues for the Vanderburgh County Health Department.
"The cumulative effects of NOx controls at Alcoa and the other utilities should definitely bring our ozone levels into compliance with a margin of safety," she said. "Additionally, it is possible it could also impact our fine particulate noncompliance."
Despite the hot weather of recent weeks, Alexandrovich said that the area has escaped high ozone levels.
"We are in good shape so far," she said.
Alcoa's selective catalytic reduction unit - a boxy, 10-story structure wrapped in steel-mesh catwalks - will operate during ozone season, Darling said. Construction of the unit lasted 18 months, finishing in spring 2003. The project required 1,300 cubic yards of concrete and 1,700 tons of steel. It took 250,000 man-hours of labor.
The selective catalytic reduction process will lower the power plant's nitrogen oxide emissions from 280 parts per million to 45 parts per million, Parenti said. That is a reduction of approximately 1,660 tons from May through September, an amount that compares to nearly the annual total of nitrogen oxide emissions from all vehicle traffic in Warrick County, Alexandrovich testified at a public hearing for the pollution controls in March.
The process uses nearly 7,000 gallons of the ammonia solution per day, which Parenti likens to "very strong Windex."
Alcoa owns the generating unit in a 50-50 partnership with Vectren, and has been responsible for its operation since March 2001, Darling said.
The company owns and operates its three other, smaller generating stations by itself, Darling said. The four power plants combined produce 732 megawatts of power. That is enough to power 200,000 homes, he said.
Unlike utilities, Alcoa has been unable to recoup some of the expense of the pollution controls by increasing rates - something which has eased the impact for companies such as Vectren. Instead, Lambert said, the company has had to tighten its belt and become more efficient.
However, besides reducing pollution, there are some additional benefits of the new pollution controls for the company. Any reductions it achieves in nitrogen oxide levels above the required cuts can be translated into emissions credits that other companies can buy from Alcoa and use to help reduce the amount of their own pollution reduction requirements.
Also, Lambert said, the new controls at Alcoa Warrick Operations will account for nearly a third of the company's own worldwide pollution-reduction goals.
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Dave Parenti, environmental projects manager at Alcoa-Warrick Power Plant, explains that the pipes are selective catalytic-reduction units that can reduce the nitrogen oxide that causes ozone. The latest pollution controls, implemented this month, are expected to help cut the ozone levels in the Tri-State.
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