Sustainable Transportation Energy Pathways (STEPS)
Available online at doi: 10.1016/j.jclepro.2009.03.003
Kendall, Alissa and Brenda Chang (2009) Estimating Life Cycle Greenhouse Gas Emissions from Corn-Ethanol: A Critical Review of Current U.S. Practices. Journal of Cleaner Production 17 (13), 1175 - 1182
This study reviews corn–ethanol life cycle assessment studies and modeling tools to identify key discrepancies between studies, and shortcomings in analysis of greenhouse gas emissions. The primary conclusions are that direct land use change modeling, soil N2O emissions modeling, and co-product crediting were either poorly treated or treated inconsistently across most or all studies. Despite the existence of improved methods and tools proposed by institutional bodies and the broader research community, the state of the practice tends towards over-simplified and highly generalized methods that increase potential uncertainty in greenhouse gas estimates and prevents differentiation among producers of corn ethanol.
Keywords: biofuels, life cycle assessment, corn–ethanol, greenhouse gas emissions, co-product allocation