The production and use of bioethanol derived from corn stover
is integrated in and supported by the energy database developed by
the GREET model. The system boundary covers the whole process
from feedstock cultivation to ethanol combustion (WTW), which
includes: 1) Feedstock growth at farming level, where agrochemical
inputs, energy inputs and emissions due to corn stover removal
were included; 2) bioethanol conversion processes, which were
modeled by Aspen Plus software; 3) fuel combustion in the lightduty
vehicle as E100 or E10; 4) other auxiliary processes like
transportation and preprocessing of the feedstock, denaturing and
transportation of the ethanol, blending of ethanol with gasoline,
and transportation and distribution of the fuel. The system
boundary of E10 fuel is shown in Fig. 1. For E100 fuel, the system
boundary is similar with that of E10 except that the processes of
ethanol denaturing and blending are removed. As the upstream
part of WTW, the stage of WTP covers feedstock cultivation
through transportation of ethanol to the bulk terminal.
Feedstock growth at farming level, where agrochemical
inputs, energy inputs and emissions due to corn stover removal
were included