When you're talking with someone about ethanol and they say, "Yeah, but it takes more energy to produce ethanol than the energy you get out," ask them if they have heard of GREET, the Greenhouse gases, Regulated Emissions and Energy use in Transportation model developed by Dr. Michael Wang.
Wang, of the respected Argonne National Laboratory's Center for Transportation Research, has found that the fossil fuel energy input per unit of ethanol is lower (.78 British Thermal Units for each 1 million Btu of ethanol delivered) compared to 1.23 million Btu of fossil fuel energy consumed for each 1 million Btu of gasoline delivered. Check out www.1eere.energy.gov/vehiclesandfuels/pdfs/program/ethanol_brochure_colo....
In the past, some researchers have calculated total input. This includes solar energy, which is free, renewable and environmentally benign. Argonne National Lab points out that solar energy should not be taken into account in energy balance calculations.
The Laboratory adds that while the total energy needed to produce a unit of ethanol is more than the total energy needed to produce a unit of gas, ethanol is superior when calculating either the amount of fossil fuel energy needed or the amount of petroleum energy needed.