BRAZIL ETHANOL ALTERNATIVE http://energybulletin.net/21064.html( Read more... )USA
To replace all its gasoline (140 bln gal/yr) with ethanol from corn, the USA would need, at present yields of 400 gallons/acre/year, almost 350 million acres of dedicated corn, not including any corn for humans or animal feed. But all the present USA area cultivated with corn is only 75 million acres (FAO, Faostat, 2005)
It would require 297.5 million acres for E 85. Or 35 million acres for E10.
At present moment, USA needs almost 400 000 bbl/day of ethanol but produces 300 000+ bbl/day. This is just to replace MTBE, as required by law. So, imports and new plants are supposed to fill the gap.
But corn and sugar cane are very different
Sugar cane is a semi-perennial culture (6-7 years cycle) that needs far fewer nutrients (fixing nitrogen from air through Gluconacetobacter diazotrophicus, for example) than corn. It is the less soil-eroding large crop in Brazil because soil remains covered most of the year or all year round. Sugar cane in Brazil is not irrigated.
All energy for the industrial process comes from bagasse burned in high pressure boilers, providing all thermal, mechanical and electrical energy needed, with at least 10% surplus electrical energy sold to the grid. Corn needs natural gas or fuel oil and electricity from the grid to supply its process-energy demands in the factory.
Ethanol yield (gallons/acre) for sugar cane under good tropical conditions is double that for corn. For all those reasons, sugar cane ethanol is seven times more energy efficient; its net energy, expressed as ERoEI, is 9:1 while corn ethanol has an ERoEI of only 1.3:1.
Conclusions
So, apart from considering whether USA corn ethanol is an energy efficient product or not (what I’m not doing here), one thing must be stressed: sugar cane ethanol from Brazil is NOT a realistic target or a comparable model for USA ethanol from corn. It is very easy to replace all gasoline when you would only need 8 billion gallons per year and you have a generous plant that thrives rain-fed under tropical conditions, occupying less than 1% of a country’s arable land, to produce alcohol to replace 50% of all that gasoline. However, this cannot be extrapolated for USA’s conditions, neither for corn, not even for sugar cane in Southern states. So, realistically, let’s understand that sugar cane ethanol in Brazil is mangoes and corn ethanol in USA is apples.
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