Wood chips may pose problems when Charter Street plant converts to biomass
From an article by Jessica VanEgeren in The Capital Times:
For decades, pollution spewed from factories and power plants across Wisconsin.
As a result, air and water became polluted. Now it seems, so did the trees.
At a time when state-owned power plants are ditching coal and going green by including biomass such as switch grass, compost, and wood chips into the fuel mix, it is becoming evident that even trees may release harmful chemicals when burned for energy.
“We have so much mercury in our air that you do see mercury in the wood from our trees,” says Jennifer Feyerherm of the Sierra Club’s Midwest office and its national Beyond Coal Campaign. “The air was polluted for so long that our ecosystem has absorbed the pollution. When wood is burned, the mercury is going to come out.”
Burning anything but coal or other fossil fuels appears to be such a new concept that the Environmental Protection Agency is only beginning to catch up. Earlier this summer, the EPA began efforts to update the Clean Air Act by releasing preliminary, first-of-a-kind numbers on what sort of pollution, if any, is emitted from burning biofuels. An early finding: Burning too many wood chips can release too much mercury into the air.
With construction soon to begin to convert the Charter Street Heating Plant, the largest state-owned power plant, from a coal-fired power facility to one that primarily burns biomass, state officials are paying attention to what is happening in Washington.
“To ignore what is going on (at the EPA) … is to do so at our own peril,” says John Melby, air management bureau director with the Department of Natural Resources. “After spending $250 million on the Charter Street facility, we don’t want to be violating EPA rules.”
While Melby says he “does know that mercury may be an issue with tree bark,” he and other state officials question the thoroughness of the EPA’s methods. In short, Melby and others believe different sizes of boilers need to be tested along with varying amounts of wood chips and other wood products before the EPA updates the Clean Air Act.