AVAILABILITY OF BIOMASS
A large, reliable, economic and sustainable feedstock
supply is required for a biorefinery. Current yields for
ethanol from agricultural residues (corn stover, straw
from wheat, rice and other cereals, and sugarcane
bagasse) are about 65 gallons per dry ton.10 Thus, a
moderately sized 65 million-gallon-per-year cellulosic
biorefinery would need 1 million dry tons per year of
feedstock. This could require 500,000 acres or more of
cropland—a supply radius of at least 15 miles. The actual
supply radius could vary from 15 to 30 or more miles,
depending on crop rotation, tillage practices, soil characteristics,
topography, weather and farmer participation.
Research at a variety of sites indicates that economic
delivery of crop residues is achievable at this radius
and beyond—up to 50 miles from the biorefinery site
when short line rail transport is available.11 So, cellulosic
biorefineries of well over 100 million gallon
capacity are possible.
To sustain a commercial-scale biorefinery, cropland
surrounding the site should meet the following criteria:
n Large Area: Minimum of 500,000 acres of available
cropland;
n Sustainable: Cropping practice maintains or
enhances long-term health of the soil;
n Reliable: Consistent crop supply history with dry
harvest weather;
n Economic: High-yielding cropland; and
n Favorable Transport: Easy access from field to
storage and processing facilities.
