The efficiency for ethanol is HORRIBLE compared to gasoline. Even the government admits this. It will not nor would work on its own without subsidy for schemers, granaries and middleman corn whores and politicians.
We had a station that sold pure gasoline a few years back. Doing comparisons, I got 15% better mileage over 10%-ethanol blend. Problem was, it cost 15% more and they went out of business. There is another station around that sells it but it’s 20 miles out of my way.
Yes, thus the irony in the mandate for higher fuel economy and the concurrent push toward more ethanol in fuel blends. All I know is, I had a Jeep Cherokee that would consistently get me 18.5-19.5 MPG commuting with its straight 6 (depended on A/C use). When the stores in my area started running alcohol blended fuel, my MPG dropped to about 17.5-18.