A study released from University of California-Berkeley finds that for every unit of energy yielded by ethanol, it takes 1.3 units to produce it from corn, and is nearly 3 times more expensive than gasoline per unit energy delivered. The study didn't take into account the $3B in federal and state subsidies that are given out to ethanol producers every year, which means that the true cost of ethanol is likely even higher. Ethanol is widely used as a fuel additive across the country, and in some areas can be found as a blend where it's the primary source of energy (so-called E85 is comprised of 85% ethanol and 15% gasoline, and must be used only in vehicles designed for it). Since ethanol can be made from corn or other sources of biomass, it's attracting much attention as a source of renewable energy.
Additionally, ethanol might lead to more pollution than the highly toxic MTBE that it replaces. This is because
bacteria in the soil prefer ethanol to gasoline (a choice that many of our readers will agree with), and therefore will
break down less gasoline before it reaches underground water sources.
Fans of biodiesel will find that their fuels didn?t fair much better, with soybeans yielding similar results to corn-based ethanol, and sunflower-based biodiesel production requiring 2.2 times the amount of energy the fuel eventually yields.
Based on this information, it appears that we haven?t found a ?free ride? yet. It would take significant improvements in the fermentation process to bring ethanol into parity with fossil fuels, but alternative sources of biomass such as rapeseed and algae have shown promise for biodiesel production (they were not included in this study, and as such it?s be justifiably criticized). For the time being, it?s probably best to think of such fuels as energy storage mechanisms, and not actual energy sources.