E85 is less energy dense than gasoline, so it puts out about 8 kWh per gallon usable. Therefore if your power bill is 20 cents per kWh then the equivalent E85 price is $1.60, so electricity is still usually cheaper.

Another problem with E85 is that it's really not that hard to adapt a car to run on it, and you're not the only one having that idea... As fleet operators like delivery companies start discovering it, the price is going to get pushed upward until the advantage is gone.