Environmental Engineering Reference
In-Depth Information
greenhousegasemissionsispropagandafromagribusi-
ness (I think Calvin would agree). Sugarcane is one crop
that does give the promised bene
its but even its long-
term contribution to reducing greenhouse gas emissions
depends on how land is used. There is an intensive
worldwide research program aimed at developing much
more effective biological sources of fuel, but as of the
writing of the
first edition it had not yet reached prac-
ticality. Now,
veyearslater,itstillhasnotreached
practicality.
It is useful to remember that the original justi
cation
for biofuels programs was to reduce dependence on
imported oil. Today in the United States because of shale
oil, in Canada because of oil sands, and in Brazil because
of the discovery of undersea oil off its coast, that is no
longer the justi
cation in those regions. It still may be for
other parts of the world.
Here, I will discuss what is happening now and what
might happen in the future. Even if the new methods do
prove to be effective, biofuels cannot be the entire answer
for transportation, nor should they have to be. As I said
earlier, there is no one magic bullet that can solve all of
our problems.
The theory behind the hope for bioenergy is simple.
Plants get the carbon used for growth from CO
taken
out of the air, turning the carbon into stems, leaves, and
fruit while returning the oxygen to the atmosphere.
Sunlight provides the needed energy to drive the photo-
synthesis process that does the job. In a sense all bio-
energy is a form of solar power. If plant material can be
ef
ciently made into fuel, burning that fuel only returns
to the atmosphere what the plant removed in the
rst
