There are two distinct reasons why ethanol is used in gasoline. One is that it serves as an oxgenator, and makes gasoline combustion more efficient. This reduces tailpipe emissions and smog. Previously, the additive MTBE was used for this purpose. The problem? MTBE is more expensive, toxic and carcinogenic, and was starting to be detected in groundwater in some areas. So they switched from MTBE to ethanol as an oxygenator in gasoline. This is clearly a superior alternative for this purpose, and there is really no reason to oppose it.
The second distinct reason for using ethanol in gas is more controversial. This is part of the EPAs agenda to increase the use of renewable fuels to increase energy independence, and reduce CO2 emissions. This accounts for the remainder of the E10 blend beyond the amount necessary as an oxygenator. Because there really was no commercial ethanol industry at the inception of the Renewable Fuel Standard, they mandated ethanol in steps. The first step is corn-based or first-gen ethanol, the next is cellulosic ethanol, which should make up most future growth in the industry.
Ethanol in gasoline was never more than an excuse to keep driving SUVs and having accidents in our pants whenever toilets back up at nuclear power plants. Even if ethanol production were "carbon neutral," we would be no further ahead than if we improved to fuel economy of our cars by 10%. If the price of ethanol collapses, perhaps people can start investing in real green energy, like solar power.
Ethanol, at least as presently used, is... in large part, a case of "greenwashing", rather than true, functional renewable energy. If we figure out cellulosic ethanol (that is, ethanol made from non-edible cellulose instead of edible grains), then we can talk...
Alternately, there's technology that can turn almost anything carbon-containing into a mixture of gasoline and methane (and appropriate byproducts), there's a plant somewhere in New England or thereabouts that's turning turkey waste into fuel. That might be a better technology path for liquid biofuels.
Ethanol reduces the fuel efficiency of cars, and the mandate is primarily because of lobbying by Archers Daniel Midland Corporation.
I thought even alarmists thought ethanol was a bad idea.
http://theweek.com/speedreads/index/2602...
http://247wallst.com/energy-business/2014/10/19/why-it-matters-that-ethanol-prices-are-collapsing/
