Filling up my truck today, I noticed a sticker on the inside of the fuel door that reads "Unleaded or ethanol fuel only." Ethanol fuel? I checked the owner's manual, and sure enough, I'd been driving a flex-fuel vehicle for two years and didn't even know it. I didn't think a 2001 Ford Ranger would be an FFV, but apparently they were already making them that early. I looked at the yellow-handled pump at the other side of the station with a big "E85" sign on it. There are only 19 fuel stations in Texas that sell E85, and I just happen to live less than a mile from one of them. Suddenly I am no longer living in the gasoline prison I had long accepted as an unchangeable fact; alternative fuels were available to me (well, 85% alternative anyway) at this very moment.

I'd already have a tank full of E85 if it weren't for the economics. Currently the E85 is being sold for about 10% less than gasoline. However, ethanol has a lower energy density than gasoline, which means less mileage. In order to be economically competitive with gasoline, E85 would have to cost 25%-30% less than gasoline. But I don't see gas prices going anywhere but up, so it might soon be cheaper to drive on E85.

Does anyone here have experience with using ethanol fuel? What are the downsides? Will anything in the fuel system or engine corrode faster, even though they're supposed to be constructed of less corrodible materials?

Ethanol is less corrosive than gasolene, IIRC.

As for energy density, why don't you try it for awhile and see if Ethanol indeed has a lower energy density?

Despite the (theoretical) energy density of gasolene, remember that gasolene needs additives to prevent knocking/early-combustion, and these additives are extremely toxic / environmentally-unfreandly.

IIRC, Ethanol needs no such toxic additives.

CMIIW.

Actually, ethanol is a LOT MORE corrosive than gasoline. So much so that it can't be pumped through existing infrastructure and cars have to be modified to run it.

Ethanol's energy density is LOWER than that of gasoline.

Whether or not ethanol production and use results in a net energy gain or loss is the subject of much debate.

I was going to say the same thing. People should be made aware if the net energy gain is negative. People should also be aware of the effects on the food supply. I feel that in the US, promotion of ehtanol isn't much more than pandering to the mid-west.