If you didn't use Corn ...
... then you'd probably be a lot better off. It's actually the insistance of US Biofuel makers in using Corn (which is horredously hard to convert into Ethanol) rather than, say, Sugar (which is easier, not easy, but easier).
But that's what you get when you have a massive farming lobby that insists people buy their corn.
As always you can "fix" figures by specifying what you measure ... for example how come Brazil has managed to go solve this problem and the US has not?
Of Particular interest is the section "Comparison with the United States" which contains the real jem;
"The fundamental issue is that the energy balance of ethanol produced from Corn is negative. It is necessary approximately 1 joule of source energy (Fossil Fuel, Electricity, etc...) to produce 0,7 joules worth of Ethanol energy, given current technology. In other words, Corn ethanol is not viable as a source of energy as it wastes more than it generates. Sugar Cane ethanol, on the other hand, after 3 decades of reasearch, have reached 1 to 8 joules of energy production balance, that is, 1 joule is spent to produce 8 joules worth of ethanol energy."