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DE Pauley wrote:
Try http://www.unh.edu/p2/biodiesel/article_alge.html
The USDA claims 3.2 units for 1 unit input for biodiesel from soybeans.
The report does not show how this is determined. UNH claims higher
production from alga; again not well supported. In either case about
10% ethanol or methanol is needed for the final biodiesel production.
Growing soyabeans to produce biodiesel would require all of the
available arable land; as a minimum, it would probably require more.
Using arable land to produce fuel is dumb, within a very few years all
arable land - and more - will be needed for food production. Alga
production on non arable land may be feasible but only if
ethanol/methanol can be produced using non arable land.
Using arable land and water is OK, as long as they are available.
However, as you point out, there isn't much left and as the world's
population grows, all will be needed for food production. Soybeans
are a stopgap measure, and cannot produce the amount of oil needed
for diesel.
Some varieties of marine algae contain 60% oil. Most of the oil can
be extracted by pressing. Some algae can double their count/mass
daily, and other algae species also grow very fast.
The only algae farms grow the health food called spirulina. They
report about 10x more mass per acre than land plants; although, it
is supposed to be more expensive to grow than corn.
Marine algae can be grown in the sea, or on land with brackish
groundwater or nearby seawater. Much land that meets this
description is desert. Arable land is not needed to grow marine algae.
--
Humbly--Ed
"If the man doesn't believe as we do,
we say he is a crank, and that settles it.
I mean, it does nowadays, because now we
can't burn him." (Mark Twain)
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