The Miracle of Ethanol?

October 09, 2011

I just read an interesting post over on the big picture agriculture blog. The post, "The U.S. Corn Crop Accounts for 65% of Nitrogen Use by Farmers," shares data from a recent USDA research report on Nitrogen fertilizer use.

Per the post, corn accounts for, "65 percent of the 8.7 million tons of nitrogen applied by farmers each year."

Ethanol production converted roughly 38% of the corn produced in the U.S. in 2010.

This leads to the following calcs which show that we now use 2.15 million Tons of Nitrogen fertilizer in growing corn to convert into ethanol.

In 2010, the U.S. produced 13.23 billion gallons of Ethanol, a 75x increase from the 175 million gallons produced in 1980. This fuel was produced at 204 Ethanol plants, 150 of which have gone into service since the year 2000. Knowing that, I wouldn't expect the trend toward greater Ethanol dependence to shift without a drastic change in D.C.'s political waters.

Another USDA study makes the following claim about Ethanol production, "Corn ethanol is energy-efficient, as indicated by an energy ratio of 1.34; that is, for every BTU dedicated to producing ethanol there is a 34-percent energy gain." That sounds great doesn't it? Take a unit of energy and magically turn it into 1.34 units of energy. Oh the marvels of modern science! Except it's not that clean. What they leave out in the discussion of efficiency is the source of the energy gain. The corn. The USDA's Amber Waves site states the following about corn to Ethanol conversion:

With a corn-to-ethanol conversion rate of 2.7 gallons per bushel (a rate that many state-of-the-art facilities are already surpassing), the U.S. ethanol sector will need 2.6 billion bushels per year by 2010—1.2 billion bushels more than it consumed in 2005.

A bushel of shelled corn weighs 56 pounds. Therefore, you need 20.47 pounds of corn to create one gallon of fuel. Over a third of a bushel of corn is used in turning the energy equivalent of one gallon of ethanol into 1.34 gallons of ethanol. This seems a prudent time to remind you that "One in six Americans is fighting hunger," and that those who are dealing with hunger might look at the miracle of burning 20 pounds of corn, in the name of creating a third of a gallon of Ethanol, might not see it in quite the same light. Don't take my word for it, ask Elmo.

flickr/mark sebastian