Ethanol was banned in the late sixties at Indianapolis Speedway after some fires (ethanol flame cannot be readily seen by the human eye). Further pressure was put on ethanol use indirectly by fuel quantity restrictions intended to restrain the upward increase in average speed and resulting high energy, high injury crashes, and ethanol has a far lower caloric content than comparable hydrocarbon fuels, so racers trying to get as far as possible between pit stops abandoned ethanol with nary a whimper. We note the recent Triumph land speed record attempt used ethanol, in order to use blown engines with extra high compression ratios, and ethanol's one advantage over comparable hydrocarbon fuels is a research octane rating of approximately 113.
So why has it risen its ugly head once again? -- POLITICs -- and more specifically FARM POLITICS.
Over the years, industrial agriculture has increased the efficiency of crops, which has depressed prices. Farmers throughout the history of man have been favored by most governments, and we are no different, and in 2008 fuel scare, the farm belt garnered enough votes to favor ethanol blending in fuel.
In every other respect, this is BAD SCIENCE, and BAD ECONOMICS.
Ethanol lowers fuel mileage as other posters have noted as its combustion produces less energy per mass.
Ethanol is a net energy consumer, given what is required to cultivate and harvest, process, and transport the crops -- in this case corn.
The corn in question could feed people, so this is another strike against ethanol.
Someday -- an aside here -- there will be enzymatic cracking of saw grass and such plants that are no use to the human food chain, and that will be a different argument.
In the mean time, every time you and I pull up to a pump that has the sticker "this fuel contains ethanol" you and I are experiencing BOHICA where politicians have yet again, reached into our pocket anonymously to send money to their special interests. And we pay twice, because we have to fill up more often, and worry about possible issues with our engines.
So when you get that notice from the American Motorcycle Association requesting you contact your elected representative to urge them to vote against the EPA mandating more ethanol in our fuel, do it, with a vengeance. Tell all your friends too. Ethanol is bad for everyone EXCEPT a handful of big corn growers.