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Marty R. Schmer,
mschmer@unlserve.unl.edu1, Kenneth P. Vogel,
kpv@unlserve.unl.edu1, Robert B. Mitchell,
rmitchel@unlserve.unl.edu1, and Richard K. Perrin,
rperrin@unlnotes.unl.edu2. (1) Grain, Forage, and
Bioenergy Research Unit, USDA-Agricultural Research Service, 344
Keim Hall, East Campus, Lincoln, NE 68508, (2) Agricultural
Economics, University of Nebraska-Lincoln, 314A Filley Hall, East
Campus, Lincoln, NE 68583
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| Switchgrass (Panicum virgatum L.) is a
potential, herbaceous feedstock for cellulosic ethanol in the USA.
Estimates on switchgrass energy inputs and ethanol energy yields are
highly variable and are largely based on small-plot research. A
five-year, field-scale trial was completed on 10 farms in the Northern
Great Plains to evaluate the energy balance for switchgrass grown for
cellulosic ethanol. Energy balances were calculated using the energy and
resources group biofuel analysis meta-model (EBAMM) model based on known
farm inputs. Nitrogen fertilizer, diesel fuel, and herbicides accounted
for 62, 17, and 10%, respectively, of average agricultural energy
inputs. Net energy values averaged 21.6 MJ L-1 with a range
of 16.9 to 23.7 MJ L-1 for the ten farms. The EBAMM model
showed that switchgrass on average produced an estimated 13.5 MJ of
ethanol for one MJ input of petroleum. |