Natural Resources Research, Vol. 14, No. 1, March 2005 (
Ethanol Production Using Corn, Switchgrass, and Wood;
Biodiesel Production Using Soybean and Sunfower
and Tad W. Patzek
Received and accepted 30 January 2005
Energy outputs from ethanol produced using corn, switchgrass, and wood biomass were each
less than the respective fossil energy inputs. The same was true for producing biodiesel us-
ing soybeans and sunFower, however, the energy cost for producing soybean biodiesel was
only slightly negative compared with ethanol production. ±indings in terms of energy outputs
compared with the energy inputs were:
Ethanol production using corn grain required 29%
more fossil energy than the ethanol fuel produced.
Ethanol production using switchgrass
required 50% more fossil energy than the ethanol fuel produced.
Ethanol production using
wood biomass required 57% more fossil energy than the ethanol fuel produced.
production using soybean required 27% more fossil energy than the biodiesel fuel produced
(Note, the energy yield from soy oil per hectare is far lower than the ethanol yield from corn).
Biodiesel production using sunFower required 118% more fossil energy than the biodiesel
Energy, biomass, fuel, natural resources, ethanol, biodiesel.
The United States desperately needs a liquid
fuel replacement for oil in the future. The use of oil
is projected to peak about 2007 and the supply is
then projected to be extremely limited in 40–50 years
(Duncan and Youngquist, 1999; Youngquist and
Duncan, 2003; Pimentel and others, 2004a). Alter-
native liquid fuels from various sources have been
sought for many years. Two panel studies by the
U.S. Department of Energy (USDOE) concerned
with ethanol production using corn and liquid fuels
from biomass energy report a negative energy return
(ERAB, 1980, 1981). These reports were reviewed by
26 expert U.S. scientists independent of the USDOE;
the ²ndings indicated that the conversion of corn into
ethanol energy was negative and these ²ndings were
College of Agriculture and Life Sciences, Cornell University,
Ithaca, New York 14853.
Department of Civil and Environmental Engineering, University
of California, Berkeley California 94720.
unanimously approved. Numerous other investiga-
tions have con²rmed these ²ndings over the past two
A review of the reports that indicate that corn
ethanol production provides a positive return indi-
cates that many inputs were omitted (Pimentel, 2003).
It is disappointing that many of the inputs were omit-
ted because this misleads U.S. policy makers and the
Ethanol production using corn, switchgrass, and
wood, and biodiesel production using soybeans and
sunFower, will be investigated in this article.