So, it appears that those who say producing ethanol takes more energy than it returns only gave us half the story:
Energy balance in the United States
One study has concluded that the use of corn ethanol for fuel would have a negative net energy balance. Namely, the total energy needed to produce ethanol from grain ? including fermentation, fertilizing, fuel for farm tractors, harvesting and transporting the grain, building and operating an ethanol plant, and the natural gas used to distill corn sugars into alcohol ? exceeds the energy content of ethanol. However, all subsequent studies have concluded that ethanol production yields more energy than it consumes (most agree on a ratio of 1.34:1) This is remarkable when one considers that the two primary sources of fuel for transportation (diesel and gasoline) have a negative energy balance. Both consume about 20% more energy than they yield. [9]