I've recently come to a decision. In Wisconsin (along with many other states), they require about a 10% blend of ethanol in regular unleaded gas. It's no secret that ethanol results in lower fuel economy, but it's also cheaper than straight gas. During a road trip not too long ago, I got to go out of state and get ahold of straight regular gas and saw just how much of a milage difference there was between the two. I also noticed that in WI, premium unleaded is generally ethanol free, and the smallest price difference was about $.20 between the two options. Without going through all the math, I'll just say I found out that a small 2 mpg increase would break even on net fuel costs by going with ethanol free premium.
Since then, I've tried running the e-free premium to see if I got the same mpg increase. In the summer, I could get about 32 mpg on my 2002 Ford Focus. 35 on a good day. That's running almost all highway, 1/3 at 65 mph, 2/3 at 55-60 with some small towns to slow down through. I just finished my first full tank of e-free premium (had to make sure the E10 was all flushed out), and I got right about 40 mpg on the same run. Keeping in mind that includes colder/denser air and more idling as I run my defrosters to keep windows clear of snow, I expect to see an even bigger difference when I get back in to the summer months.
I also started poking around a bit online and listening to a few things on the radio about ethanol production. Seems there's a big controversy where some scientists claim it takes more energy to make ethanol than is contained in the fuel itself, meaning the enviromental impact is actually worse than using straight gas and is not offset by the cleaner burning of the ethanol. I also ran across one story from
Edmunds that measured only a 0.5% reduction in CO2 when using E85 over straight gas (so I'd assume a smaller difference when using E10). On the other hand,
How Stuff Works reported a 10 ton reduction in green house gasses in 2007 attributed to ethanol blends and WI had a lot less high ozone alert days. So it seems there's no clear answer yet on if ethanol is really as eco-friendly as enviromentalists lead us to believe.
Given all this, I'm sticking with straight gas for my Focus or doing highway driving, even if it means buying premium. Ethanol would have to be drastically less for it to be economically benefitial to run a blend, which you just wont see at a pump these days. Then there's also the questionability of its enviromental impacts that take away that excuse for the higher running costs. The only other benefit is it does help reduce our oil dependency, but that's also offset by cutting in to corn food supplies and causing those prices to go up. It also seems milage differences may be debatable in my mate's car when she does mostly city driving. Considering how long it takes her to go through a tank and how the conditions can vary wildly on a single tank, it's been hard to say so far if there's much of a difference in city driving. So that one we're running the regular gas with E10 unless taking it on a decent highway run. When spring comes back around and road conditions stabilize, we'll try it again.
After saying all that, I'm curious what others views are on running straight gas, E10, or E85. Anyone look in to this and come to differing conclusions? Do you just buy what ever is cheapest at the pump or easiest to access? Or do you go out of your way to buy one fuel over another? As a side note, I'm not saying that premium itself is better when a car doesn't require it. That's common knowledge that it isn't. My only reason for bringing it up is because the only straight gas I can find around here is premium and the milage increase I get offsets the price difference.