Biomass and Coal: A Powerful Combination

Biomass Power & Thermal
By Anna Austin August 23, 2011

Biomass Power & Thermal investigates potential technical and safety issues involved in storing and handling biomass at cofired power plants.

When Minnesota Power began cofiring coal and biomass at its power plants in Duluth and Grand Rapids, Minn., more than 20 years ago, they started out combusting 75-25 coal to waste wood ratios.
Back then, biomass was plentiful and cheap and it was common to get it for free, says Mike Polzin, renewable fuels coordinator for Minnesota Power. “We started burning wood in Duluth only because a new paper mill had bark they had to get rid of and they didn’t know what to do with it,” he says.

That has changed significantly as the years have gone by, as biomass has become a hot commodity. Competition for material has become stiff and in many cases can be pricey. Still, certain incentives that have come into play during that time—such as state renewable energy credits—make it enticing for power utilities such as Minnesota Power to use more biomass.

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