Jim Letourneau's Blog

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Ethanol Limits

We previously posted links to Lester Brown's comments on the limits to ethanol production.

The grain required to fill a 25 gallon SUV tank with ethanol will feed one person for a year.

We liberally used Lester Brown's comments during our Howe Street.com interview. While making for a great sound bite, I hadn't actually checked out the numbers so it was time to do a bit of due diligence.

For every one bushel of corn, approximately 2.7 - 2.8 gallons of ethanol is produced.

The Hummer HI has a 53 gallon tank

This means that 19.27 bushels of corn are used to fill the tank (at 2.75 gallons/bushel).

Corn can weigh anywhere from 45-70+lbs/bushel. Using 56 lb/bushel
(http://www.unc.edu/~rowlett/units/scales/bushels.html) leads to 1079
lbs of corn being used to fill a hummer tank.

An ear of corn weighs anywhere from 5.4-9.6 oz. so if we use an 8 oz
ear of corn we get 2158 ears of corn. That would give a corn eater 5.9
ears a day to live on. Close enough!