Alliant Energy’s Combustion Initiative has managed to halve damaging nitrogen oxide (NOx) output from one of its coal-fired power plants, using a new science and technology-based approach, according to a company statement. It said that reduction had been achieved at a fraction of the cost of installing traditional emissions-reduction equipment. The Wisconsin energy services company now intends to use the technology at its remaining coal-fired plants.

“We’re very excited about these promising results, and we expect to see even more improvement as the project moves ahead at our other plants,” said Erroll Davis, chairman, president and CEO of Alliant Energy. “We believe cost is no longer a significant barrier to NOx emissions.

In winter of 1999, the Alliant’s ML Kapp power station in Clinton, Iowa had a nitrogen oxide (NOx) emissions rate of approximately 0.35 pounds per million British thermal units (Btu). Through conducting research, implementing computer modelling, installing new equipment and fine-tuning existing machinery, the facility lowered its NOx emissions rate to about 0.15 pounds per million Btu. Alliant Energy is continuing to optimize the equipment at this plant in hope of reducing emissions even further.

Nitrogen oxide is a key factor in creating smog, ozone problems and acid rain. Coal-fired power plants owned or partly owned by Alliant in Wisconsin emitted 43,000 tons of nitrogen oxide in 1998; that figure was down to 36,500 tons in 2000, mainly because the Rock River coal plant was converted to natural gas last year, spokesman Paul Bauman said. The average residential customer uses about 620 kWh of electricity a year, enough to send 36 pounds of nitrogen oxide a year into the atmosphere.

Alliant declined to disclose just how they accomplished the pollution reduction, but they said it involved installing more monitoring equipment and experimenting with equipment in the combustion process.

The advanced clean-coal option is being implemented at the Edgewater Generating Station in Sheboygan, Wisconsin and has also begun at seven other coal-fired plants that Alliant Energy operates in Iowa and Wisconsin.

The Combustion Initiative was developed in anticipation of more stringent environmental restrictions for NOx and other chemicals produced when coal is burned.

Alliant said that throughout the industry, many utilities are using selective catalytic reduction (SCR) equipment to obtain similar results. While these systems are effective, they are also 5-10 times more expensive to install and maintain, and are focused primarily on NOx reductions. Additional systems may be necessary to lessen the impact of other emissions.