Any car has to be able to run on 10% ethanol because it's the winter blend of gas we get in most parts of the country. Really the gas we get half of the year is technically E10 (10% ethanol, 90% gasoline). There are some vehicles that are designed to run on E85 (85% ethanol, 15% gasoline), the Insight is NOT one of these vehicles. The only vehicles designed to run on E85 are called something like flexi fuel vehicles and include mostly Chevy and Ford trucks and SUV's. We had a Yukon that would run on E85, but the only fueling station within 100 miles was government access only.
Besides, E85 would cause you to get worse mileage anyways. There is less BTU per volume compared to gas. And Ethanol is also more solvent than Gasoline so it could cause damage to the fuel system in higher doses.
yes I know all of this.. E85 need 9:1 of 10:1 for optimal fuel eco. and the gas, 14.7:1.. so yes, your MPG would be not as good as if you would run on E05 or E10.
BUT here in Sweden where I live.. E85 is around 30% cheaper than E05 and if the insights injectors and fuelpump is capable of injecting a mix of 9-10:1 fuel/air ratio where the fuel is; 1/4 E85 and 3/4 E05, it wouldent matter that the MPG were slightly worse becouse of the cheaper fuel you'd put in your car.
Besides, E85 producing less emissons than E10.. and isnt that the hole point of the insight?