Environmental Engineering Reference
In-Depth Information
Despite the success of the Brazilian sugarcane program,
Phase-
biofuels do not offer a solution to global prob-
lems. A recent analysis of the world potential for all
Phase-
].
Taking all of the worldwide production of corn, sugar-
cane, palm oil, and soybeans, and converting it into liquid
fuels gives a net energy equal to about
biofuels gives the whole, depressing story [
s global
primary fossil-fuel energy. It can have no signi
% of today
'
cant
worldwide impact on greenhouse gas emission, but can
make sense in special cases like Brazil. A large expansion of
Phase-
biofuels production can have only bad effects on
food prices with little if any effect on climate change.
.
Phase-
: Cellulosic Ethanol
Plants contain much more carbon than is recovered or
converted even from sugarcane. The walls of the cells that
make up the structure of a plant are composed of mater-
ials called lignin, cellulose, and hemicelluloses locked in a
complex tangle of
fibers are less
than one-thousandth of the diameter of a human hair,
and each is composed of a bundle of even smaller long-
chain molecules. The aim of the cellulosic ethanol pro-
gram is to
fibers. The individual
cient and affordable process to get at
this material and turn at least the cellulose and hemicellu-
loses into ethanol. Breaking down the lignin would be a
bonus. Termites do it, so why not us?
find an ef
The International Energy Agency has a good status report on second-
generation biofuels. It is available at
http://www.iea.org/textbase/papers/
/
nd_Biofuel_Gen.pdf
. They estimated that it will be
before a
commercial demonstration is done.
