Why does premium gas cost so much in Chicago?

The answer:>

The premium paid for higher-octane gas in Chicago is a byproduct of several factors, but analysts attribute it mostly to a fracking problem. Shale production has created a glut of crude oil in the U.S. But that source offers a lower-octane base for refining gasoline. Most Midwestern refineries use shale crude, according to Green.

Now, I've never heard this explanation before, but it does make some sense to me.  Fracked crude is very "light", perhaps there are not as many of the hydrocarbon species needed for high octane gasoline?

So, if this is the problem, what is the answer?

Mixing in E85, which itself has large amounts of ethanol in it, as much as 83%.  Ethanol has an octane of 120!

That is the focus of this blog going forward, how does mixing ethanol into gasoline at the pump impact the performance and reliability of a 2004 Acura TL with 153k miles on it?