In brazil theyve been running ethanol since the 80s. They say that the price of ethanol has to be 70% or less of the price of gasoline for it to be financially more efficient. We have ethanol (100% not 85%) and gasoline at every gas station (they call it gasoline but E25 would be more accurate; pure gasoline is not available). Most cars 2003+ have a sensor that tells the ECU what the gas/ethanol ratio is in the tank and the ecu will adjust the timing and the amount of fuel injected into the motor so that the car can run on 100% ethanol, 100% gas or any ethanol/gasoline mixture. Everyone is constantly comparing ethanol/gas prices over there lol.