Take one gallon of ordinary gasoline. To replace that gallon with an equivalent number of BTUs requires 1.4 gallons of ethanol. Since corn is the only significant source of ethanol touted by its lobby, let’s look at corn-based ethanol production. The process of converting corn into ethanol consumes 58 percent of the corn’s BTU content. Another 11 percent of those BTU’s are burned in moving the ethanol to the consumer at the service station. Thus, 69 percent of the energy contained in the corn is lost during processing and transportation. That leaves just 31 percent for conversion into fuel. So we take that 0.31 and divide the 1.4 gallons of ethanol (mentioned above) by it, in order to match the BTU content of one gallon of ordinary gasoline. It becomes clear that you need corn with an energy content the equivalent of 4.5 gallons of ethanol, in order to produce the 1.4 gallons we started with (1.4 / 0.31 = 4.5).

But here is the punchline. About 40 percent of corn’s calorific value comes from fossil fuels that are used during the cultivation, harvesting, and transportation of the crop. Therefore, to produce 4.5 gallons of ethanol (which remember, due to conversion losses mentioned above, yields just 1.4 gallons of actual ethanol for use as motor fuel) requires farmers to use about 1.8 gallons of ordinary gasoline equivalent, in the forms of natural gas (for fertilizer) and motor fuel (primarily diesel). Thus, to produce enough ethanol to replace one gallon of fossil gasoline, farmers and processors consume at least 1.8 gallons of fossil fuels.

Incredibly, this calculation is conservative because it assumes that the ethanol manufacturing process is self-contained, that is, that incoming corn provides all operating energy and that ethanol is transported by ethanol-burning trucks. If we use a more logical methodology, the 1.8 gallons could actually double! In short, no matter what the environmentalists, farmers, and super hawks have to say, the numbers for ethanol just don’t add up.