Cost to deliver sweet sorghum fermentables to a central mill

Cost to provide readily fermentable feedstock (juice sugar) and silage for fiber conversion, up to the point fermentation begins, was determined for three harvesting systems: forage chopper, pith combine (forage chopper modified to leave a 10 percent rind-leaf fraction in the field), and Piedmont system (allows for 30 to 60 days whole-stalk storage before processing). Costs were $1.06/gal for the forage chopper system, $1.06/gal for the pith combine, and $1.16 for the Piedmont system. The most optimistic projection of ethanol yield from fiber conversion (100 gal/dry ton) was used. No opportunity was identified for a significant reduction in feedstock cost; consequently, current market value of ethanol must increase before a sweet sorghum-to-ethanol industry in the Piedmont will be economically viable