Environmental Engineering Reference
In-Depth Information
susceptible to contamination by native algal species and evaporation and
usually produce algal oil of lower density than in more controlled
settings.
Environmental Concerns
Environmentalists have several concerns
about the production of ethanol from corn and biodiesel from
soybeans:
Clearing grassland to plant corn or soybeans releases ninety-three times
the amount of greenhouse gas that would be saved by the fuel made
annually on the land.
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So for the next ninety-three years, climate change
is being made worse, not better, by biofuels. Using naturally occurring
cellulosic perennial plants would eliminate this problem.
Conventional corn farming can remove 30 to 50 percent of the carbon
stored in the soil.
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In contrast, cellulosic ethanol production does not
deplete the soil because plants are mowed as they grow naturally, often
on land that is already in conservation reserve.
Corn is a thirsty crop, and increasing corn planting will cause consider-
able harm to the nation's water quality from increased nitrogen and
phosphorus pollution. This adds to the problem of dead zones in the
Gulf of Mexico and other water bodies like Chesapeake Bay. Cellulosic
ethanol production does not have this problem.
Corn is grown in an area where irrigation is required from the Ogallala
aquifer, which provides irrigation for much of the southern Great Plains.
The water table has already dropped signifi cantly in these areas, threat-
ening the water supply of agriculture in general. Cellulosic plants such
as switchgrass do not require irrigation.
As is true of all row crops, growing more corn means applying more
pesticides and artifi cial fertilizers to the soil. These inputs have a large
carbon footprint in addition to the poisons they add to the soil. Using
naturally occurring plants does away with this problem.
The economics of corn and ethanol production means that farmers will
grow corn on acres they otherwise would have rotated with soybeans to
restore the nitrogen in the soil. The soil becomes depleted in an essential
nutrient. Using naturally occurring plants avoids such choices.
It is immoral to use food, which is essential for human existence, to
provide fuel for cars. Naturally occurring grasses are not food.
The skyrocketing price for a bushel of corn caused by the ethanol craze
puts poor people in the position of subsidizing the motor vehicles of
wealthier people. Distilling ethanol from cellulosic plants does away with
this objection.
