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greater. For regions where the main source is coal it
would be worse. There are many calculations of the bene-
fits of ethanol-based biofuels. I have looked at many and
find that assumptions and methodology vary. The best
that I have found is an article in the journal Science [
],
and the numbers above are based on it.
The typical bushel of corn produces
gallons of
ethanol. The total corn crop in the United States amounts
typically to around
.
billion bushels per year, though this
is variable depending on the weather. The
billion gallon
ethanol mandate for the year
requires the use of
about
% of the corn crop, and the
billion mandated
for the year
would require more than the entire corn
crop (
% of it). Either advanced biofuels will be
required to meet the future mandates or much more land
will have to be converted to growing corn.
A recent report from the National Academy of Sciences
on water use [
If projected future increases in use
of corn for ethanol production do occur the increase in
harm to water quality could be considerable. Expansion of
corn on marginal lands or soils that do not hold nutrients
can increase loads of both nutrients and sediments. To
avoid deleterious effects future expansions of biofuels may
need to look to perennial crops like switch grass, poplars/
willows or prairie polyculture which will hold the soil and
nutrients in place.
] says,
As mentioned earlier the cost of food is going up, and
advocates of corn ethanol say that it is not their fault.
They are partly correct. The price of corn doubled before
the US Midwestern
floods of the spring of
. That
price increase is mainly their fault. After the
oods the
price of corn increased by another
%, which is surely
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