|What are the benefits of using vegetable based
gas as opposed to using fossil fuel?
|Question Date: 2009-04-30|
People may speak about biofuels, like vegetable
based gas, as a great replacement for traditional
fossil fuels. Although it would be a great help
to our energy crisis, it won't do quite enough.
The problem is biofuels still will produce some
pollution. Through thoughtful engineering, they
may create less pollution, but they will still
However, there is one very
useful thing about biofuels. If all we need to
make biofuels is vegetables, then it should be
pretty easy to get, because we can grow
vegetables in fields just about anywhere, whereas
for fossil fuels, we have to search around and
find it, since it came essentially from dead
plant and animal matter (hence the name fossil
fuels). It's hard to predict where this will
happen, and even then, there's only so much of it
buried in the Earth, and we're eventually going
to run out, likely very soon.
In theory, vegetable fuel is derived ultimately
from sunlight and thus is recyclable, returning
gasses into the atmosphere; they were removed to
make the oil itself. Fossil fuel on the other hand
is not recyclable and therefore limited, and
burning it alters the composition of the
atmosphere in ways we may not want.In practice,
most vegetable oil is grown with fertilizer, which
is in turn made from fossil fuels. As a
consequence, the reasons why it would be a good
idea usually don't apply.
It took millions of years to make fossil fuels,
and we're running out of them. In principle, we
won't run out of plants: we can grow new crops
every year. Some kinds of plants are better than
others for reducing fossil fuel usage. For
example, producing a gallon of fuel from corn
requires about 7/8 of a gallon of fossil fuel
because corn requires fertilizing and extensive
chemical processing. So corn doesn't save much
fossil fuel. A gallon of fuel from sugar cane, on
the other hand, requires just 1/8 of a gallon of
fossil fuel. Brazil "grows" a lot of its gasoline
as sugar cane, while we in the U.S. still have to
import most of our oil.
The primary benefit is that corn is easy to
grow so we can always produce more of it. Fossil
fuels took millions of years to create, so more
cannot be created quickly enough to keep up with
demand. You didn't ask about the downsides of
vegetable-based fuels, but I'd like to tell you
that they are very problematic as well. Growing
corn takes a lot of land, a lot of water, and a
lot of fossil-fuel-derived fertilizers. It doesn't
seem to be a good fuel alternative.
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