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  • From: Clansgian AT wmconnect.com
  • To: homestead AT lists.ibiblio.org
  • Subject: Re: [Homestead] Morning musing
  • Date: Thu, 20 Sep 2007 17:38:27 EDT



> You get about 1.3 units of energy for each unit of energy invested in
> ethanol. You get about 2 units with biodiesel.

Don, the rest of your comment sums up the real problem. If we converted all
our food into motor fuel, we'd still only replace a small per cent of the
total we use. In fact at present, we'd not even keep up with the increase in
fuel
usage.

But the above proffered figures are cooked. The 1.3 comes from the notion
that after you malt or enzyme treat the corn, you can use the spent grains
for
livestock feed and since raising livestock feed uses a certain amount of oil,
you are saving that. But notice I said "energy-wise". Right now you get the
energy equivalent of .9 gallons of ethanol out of every 1.0 gallons (energy
equivalent) you use producint it. It is a net loss. But the thinking is, it
would take the energy equivalent of .4 gallons to make the livestock feed you
have left over so the retrun is 1.3.

The trouble is, the ability to use the acidic spent grains is limited. Very
soon we would become saturated with spent distillery grains with nothing to
do
with them if fuel ethanol continues unabated. At that point ethanol becomes
a net loss and the byproducts a liability.

The same is true of biodiesel especially from soybeans. What's left over are
press cake for livestock feed and plastic manufacture. Same thing though,
soon you have so much you can't use it and the energy return goes down. Just
on
a straight up energy-in/energy-out soybeans to biodiesel is closer to 1.2 to
1.

James </HTML>




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