Environmental Engineering Reference
In-Depth Information
The new CAFE standard discussed in
Chapter
will
reduce fuel use much more and reduce greenhouse gas
emissions by
% when fully implemented. Adding
more ethanol per gallon of gasoline does very little in
comparison.
Ethanol costs more than gasoline on an energy equiva-
lent basis (
.
gallons of ethanol costs
$
.
in Decem-
ber
and has the same energy content as
gallon of
gasoline which costs
$
.
).
The cellulosic requirement for
is more than
times the amount available; all attempts to scale up
cellulosic have failed so far.
Corn-based ethanol was originally intended to reduce
oil imports. Imports are going down rapidly because of
the recent large increase in domestic production in the
United States and Brazil. Also, corn-ethanol gives only a
small reduction in greenhouse-gas emission. In a world
context, the only Phase-
biofuels that offer signi
cant
bene
ts are those from sugarcane and sugar beets. The
subsidies that agribusiness so likes for corn ethanol do
nothing but drive up food prices.
Cellulosic is potentially a different story. If it can be
scaled up, its greenhouse-gas reduction potential is sig-
ni
cant, but we will have to wait to see if it can be
produced affordably in large amounts. So far, the scale
up efforts have failed.
.
Phase-
: Other Processes
There are a multitude of possible processes other than
conversion to ethanol that can use carbon-based materials
for fuels. Some are old and some are new.
