Doing the math on ethanol as biofuelJune 4, 2013
At the start of a mostly pleasant volunteer experience at Marra Farm this past Saturday, the volunteer coordinator offered a rather politicized summary of why eco-friendly community farms like Marra are important.
One of the things she was clearly against was growing corn to produce ethanol for biofuel. She said that if a 4-acre farm like Marra was used entirely for corn production, the resulting ethanol would only be enough “to fill up the tank of one SUV.”
This sounded implausible to me, so I did some quick Internet research when I got home.
According to ethanolrfa.org (not the best possible source, but a convenient one), an acre of land can produce about 150 bushels of corn per year, and it takes about 0.36 bushels to produce a gallon of ethanol.
Therefore the ethanol output of 4 acres would be
(4 acres)*(150 bushels/acre)*(1 gallon ethanol/0.36 bushels) = 1667 gallons of ethanol.
That amount of ethanol may be enough to power one SUV for a year. Maybe that’s what the volunteer coordinator meant.