I've read a couple things on the internet, which I'm sur eare super reliable, but it's brought me to one simple conclusion... Ethenol makes no sense to me.
Firstly, let's think about this... we started using ethenol because we wanted to use less oil... I guess that would make sense if it weren't for the fact that we take oil out of the ground and crack the nitrogen out of it to be used as fertilizer for the crop that we're going to turn into ethenol.
1. We prepare the soil. (which takes diesel or propane)
2. We plant the crop. (which takes diesel or propane)
3. We spread fertilizer and pesticides (both of which have main ingredients from oil) Firstly, large amounts of energy went into making both of these products) and you need to use some machine to do that which also runs on some sort of fuel like diesel or propane.
4. We cultivate the crop (more energy used)
5. We then ship the crop to a grain elevator (more energy)
6. Grain elevator moves it all over the place eventually putting it into a hopper of the freight car on a train (possibly) (Probably uses a fair bit of electricity for this...)
7. Grain is smashed, mashed, mixed with chemicals, heated, to get ethenol (more electricity, plus factor in the energy that was used to create the chemicals)
8. Ethenol is then put into a pipeline or into tankers who then haul it to gasoline distribution points (basically the places that gasoline tankers destined for a service station get their gas along with the additivies). Here's some more energy used...
9. Gasoline ends up in your car + 10% Ethenol.
This seems like a huge number of complicated steps... and I haven't even addressed the fact that most likely that corn is some form of hybrid that was specially culitvated and harvested which used a fair amount of energy (basicially another steps 1 through 5) though the fifth step would be some private grain elevator owned by a seed company.
The other question is when you add up all the energy that was used in those steps does it equal the amount of energy derived from the ethenol? I'm not betting man, but my thinking is no, that we're seriously in the hole. Which asks the question... Yes, burning ethenol in your car is better for the environment as far as what's coming out your tailpipe, but if there are 10 other steps that aren't using ethenol, is it really better for the environment?
There are other ramifications to this as well, the main one being that you shouldn't be using your food source as a form of fuel... it creates an ugly supply/demand problem, especially in a world where there are lots and lots of starving people... The people with the money will end up with the corn in their gas tanks... not in the mouths of people who need it the most.
What's even more infuriating is that there are other technologies, like Thermal Depolymerization (I'm sure I butchered the spelling on that one!) that can turn anything organic into oil, which could then be refined into pretty much anything. Think of the billions of tons of trash that end up in landfills that could be converted into fuel, etc.
However, that doesn't solve the fundimental problem... which is... we need to get off of oil. Technologies such as TDP in the midterm will help us stop pumping the stuff out of the ground. What we need is a renewable end game. I think that will end up coming when people figure out how to make really efficent solar panels, but are capable of manufacturing them efficently as well. Solar, combined with wind, hydro and wave generation would probably generate all the energy we need.
This still leaves us with a problem... there are lots and lots and lots of cars on the road that burn gasoline... The best solution to this problem is to let market economics work themselves out. Once gas becomes impossibly expensive, it'll suddenly make sense to either use other forms of transportation to get where your going, or when your car wears out replace it with something electric / compressed air / [insert unknown technology] / bicycle OR also likely, people will create conversion shops that will for a couple of grand convert your car into an electric / compressed air / etc...