Publication DetailsTitle : Fuel-Cycle Assessment of Selected Bioethanol Production Pathways in the United States
Publication Date : November 01, 2006
Authors : M. Wu, M. Wang, H. Huo
Abstract : This report documents development of pathways of producing ethanol from corn stover and forest residues in GREET. Corn stover-based ethanol is produced via biochemical conversion process based on NREL's bioconversion process simulation. Forest wood residue is a feedstock to produce multiple alcohols, ethanol, methanol, butanol, pantenol, etc., via a mixed alcohol process developed by NREL. This work is part of a DOE OBP funded 30x30 study. We re-examined fertilizer use (nitrogen, phosphorus, and potassium) and irrigation needs in the thirteen major corn-growing states, based on current USDA data. Net nitrogen requirement and N2O emissions as a result of corn stover harvest for cellulosic ethanol production was analyzed. As part of this effort, we conducted a life cycle assessment of energy use in farming machinery for the equipment used to farm corn. The assessment accounts for steel and rubber production, refining, parts production and assembly of the equipment. A historical comparison of farming machinery-embodied energy was presented. Through this effort, GREET was expanded to include the corn stover to ethanol pathway and the forest wood residue to ethanol pathway. In addition, a farming machinery embodied energy database was included in the ethanol pathway in GREET.