The life-cycle impact category considered for this study is
global warming potential (GWP) for the emissions contributed
by the three greenhouse gases (CO2, CH4, and N2O). The three
greenhouse gases are aggregated on a carbon dioxide equivalent
basis using the 100-year horizon GWP factors of 1 for
CO2, 25 for CH4, and 298 for N2O as recommended by the
Intergovernmental Panel on Climate Change (IPCC). Thus, the
net life-cycle GHG emission for corn ethanol is determined as
g MJ1 carbon dioxide equivalent of denatured ethanol. The
life-cycle GHG emission for corn ethanol is then compared to
that of gasoline. The life-cycle GHG emission (including production,
transport, and combustion) for gasoline is assumed