Good question. I don't have any documentation to back this up, but I've heard that ethanol requires more petroleum to produce than it saves (no wonder gov't and big business are so happy about it). For biodiesel, I think there's a net reduction in petroleum consumption on the order of 3:1.
Hopefully someone here will provide more information. I've been really curious about this too.
There is a term used to express the energy yield - ethanol is 1.3 so it takes 1 barrel of oil to make 1.3 barrels of ethanol. Now I have to wonder if that is normalized energy since ethanol contains less energy per volume than oil. Biodiesel is about 1.6 if burned as oil I think instead of converted. Making biodiesel requires heating and stirring which takes grid energy and I am not sure how that enters the energy equation and also takes alcohol to process it. Dino is a positive as well or else they would not be pumping it out of the ground but the shear volume is bind moggeling.
Diesel should be better, biodiesel even better if using a waste stream, and ethanol from corn is the worst.
Originally Posted by FormulaTwo
I think if i could get that type of FE i would have no problem driving a dildo shaped car.
Ethanol if finally a positive yield due to the increase in interest (both intellectual and financial) in it these past few years. It is close to, if it hasn't yet surpassed, petroleum diesel and gasoline which are holding at about 1.3 kw energy produced for each 1 kw of energy expended.
Some may say "30%! That is terrible." I'd be happy if my 401(k) return was at half that yield.
Biodiesel is still around 3.5 or 4 kw out for each 1 kw in. Maybe I need to invest in a high oil yield algae farm....
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