An Energy “Sweet Spot”
Ethanol is mandated by the U.S. government as an additive to gasoline as an oxygenate to reduce carbon monoxide and ozone levels. This is done to replace the additive MTBE which is difficult to remove from contaminated groundwater and soil and is thought to be a major carcinogen.
Ethanol from sugar cane is seven times more energy efficient to produce than the corn based alcohol. This conversion of food to fuel requires substantial energy inputs in the process from either source. All the energy needed to convert sugar cane is derived from bagasse (otherwise unusable material from sugar cane cultivation) used as fuel for boilers which provide all the necessary thermal, electrical and mechanical energy with 10% left over. In Brazil, this excess is consumed in the electrical grid.
For every unit of energy used to produce corn ethanol, 1.3 energy units are produced. With sugar cane, this jumps to 9 units of energy output for every single unit of energy input. These figures do not include the energy required during the corn growing process which brings the input/output ratio down to nearly 1:1.
Brazil has used ethanol to become nearly energy self-sufficient and indeed sold all but two of their fleet of 27 tankers to Venezuela a few years ago. They have let the U.S. know that they are ready to export this fuel.
This begs the question of why are we still burning “food” in our gas tanks. The diversion of corn, a very basic food commodity, to a very expensive fuel source has driven up food prices all over the world. The answer is simple politics. Until last year, ethanol producers in the U.S. enjoyed a 45 cent per gallon federal subsidy while at the same time, we levied a 54 cent per gallon tariff on imported ethanol.