Biomass Feasibility Project Final Report - Xcel Energy

oth the opportunity and the motive to install systems that extract more energy from wood
waste (Larson, Consomi, and Katosfky, 2003).
The economics of paper making will drive it to increased energy efficiency. Purchased power is
a major cost for pulp and paper mills. It accounts for as much as 20% of their cost of goods sold,
about the same as the timber that forms the product itself. An investment in an efficient power
system is likely to pay for itself quickly.
Research to Turn Pulp and Paper Mills into Power Plants
Collaboration among the U.S. Department of Energy, research universities, and industry
laboratories has led to the development of several biomass gasification techniques that now are
near commercialization. Several of these technologies have undergone two or more years of
full scale commercial testing and are ready for wider adoption.
A number of studies have evaluated the potential impact of new energy technologies on the
financial performance of pulp and paper mills. An important Agenda 2020 paper, sponsored by
the paper industry calculates that a hypothetical mill now importing 36 MW to meet its electricity
needs could export 15-22 MW by using a mill-scale Black Liquor Gasification-Combined Cycle
(BLGCC) system, with no increase in the volume of black liquor it processes (Larson, 2003). In
short, by using a gasifier, a pulp mill could turn electricity from an expense into a revenue stream.
The next step, adding a larger gas turbine co-firing natural gas with syngas made from black
liquor (this would require the purchase of additional wood waste like harvest residues), would
increase the mill’s power exports to 126 MW, enough to make it small utility-scale power plant.
The implications of biomass technologies extend far beyond the economics of the mills
themselves. They presage an era of national energy independence. Sweden hopes to reach
that goal by 2030. A Swedish engineer, Ingvar Landalv, visited Minnesota several times in 2005 to
talk about a $30 million pilot plant his firm, Chemrec, has built for the Swedish government. It is a
biorefinery attached to a chemical pulp mill’s recovery boiler to produce liquid fuels. By 2030,
Sweden plans to make all its liquid fuels in pulp mills and all its electricity in nuclear plants (as it
largely does already). An American firm, Thermochem Recovery International, is working on a
somewhat different biorefining technology with funding from the U.S. Department of Energy.
Enzymic cellulosic processes also may a future role in using mill and forest wastes to make liquid
fuels.
Not every mill will adopt advanced energy technologies. Chemical paper mills probably will
lead because of their high power consumption and valuable black liquor wate stream. The
Upper Midwest will not benefit as greatly from this trend as the Southeastern United States, where
two-thirds of the nation’s chemical pulping capacity resides. Chemical mills aside, however,
more energy-efficient use of wood wastes could help any mill survive this difficult period of shutdowns
and consolidations.
Minnesota’s Pulp and Paper Industry
Minnesota is home to eight paper mills. Two of them, Liberty Paper in Becker and Rock-Tenn in
St. Paul, recycle paper and thus have no wood waste to burn. (They do remove contaminants,
like adhesives and inks, that can be used in Refuse Derived Fuel (RDF), but that is not our
subject.) Another paper mill, Wausau Paper in Brainerd, also does not generate wood waste
because it buys all of its pulp. Three mechanical mills, UPM Blandin in Grand Rapids, Stora Enso
in Duluth and International Paper in Sartell, do have wood waste to burn because they make
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Identifying Effective Biomass Strategies:
Quantifying Minnesota’s Resources and Evaluating Future Opportunities