I always wondered what the efficiencey of making etanol versus selling ethanol.
How much energy (BTU's) does it take to generate ethanol BTU's.
Ten years ago the general public thought it took more energy to produce a gallon of ethanol energy than that gallon of ethanol delivered. Thus this was called a negative energy balance.
Many studies, over the years, have resulted in a wide range of answers to the question of ethanol's energy balance, often depending on who financed the study. The general results are (continued)

In 1995 a government study stated that corn ethanol is energy efficient with a 1.24 energy ratio: for each BTU needed to produce ethanol, there is a 24% energy gain. In 2002 the USDA said the ratio is 1.34. Today there are numerous studies and it seems the public accepts a ratio in the range of 1.24 to 1.34 but discounts studies that say the energy ratio is around 1.65.
Future technology developements may get it to 1.65.
Therefore I am happy to report that ethanol factories are producing a positive situation for ethanol as an alternative energy resource to petroleum. Corn (and any other celluose product) is the ultimate solar energy resource.