Scientists with the U.S. Department of Agriculture (USDA) have figured out a cost-benefit balance between identifying the best sites for building bioenery facilities in the Pacific Northwest and supplying those facilities with the biofeedstock needed to produce fuel.
Agricultural Research Service (ARS) agronomist George Mueller-Warrant, plant physiologist Gary Banowetz, and hydrologist Jerry Whittaker calculated that the 6.2 million tons of straw left over from the production of Pacific Northwest cash crops could be used to produce more than 430 million gallons of biofuel. ARS is USDA's chief intramural scientific research agency, and this research supports the USDA priority of developing new sources of bioenergy.
The scientists, who work at the ARS Forage Seed and Cereal Research Unit in Corvallis, Ore., revised a statistical approach that had been developed by other site analysts to identify the best locations for commercial and public facilities.
Then the team used the revised program to calculate the number of biofuel conversion facilities that could be supplied by the average annual straw yield, and identified the best locations for the conversion facilities so that the costs of transporting straw could be minimized. Straw is a high-bulk, low-density commodity, which adds to the expense of moving it from field to market.
The team ran its calculations for facilities that had three different scales of annual production. Small-scale facilities could process 1,100 tons of straw, medium-sized facilities could process 11,000 tons of straw, or large-scale facilities could process 110,000 tons of straw.
After excluding straw residues left on fields to protect the soil from erosion and to help maintain soil quality, the researchers' results indicated that there was enough available straw to supply to 6,200 small facilities, 660 medium facilities, or 64 large facilities.
More than half the plants of all three sizes had sufficient supplies of straw available within a reasonable travel radius to support biofuel production, which meant that producers could potentially profit by bringing the straw to the facility for conversion into biofuel.
These findings were published in 2010 in Biofuels, Bioproducts and Biorefining.