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A study conducted by VTT Technical Research Center of Finland indicates that there's only a very slight change in overall fuel consumption between commercial-grade E10 (fuel made up of 10 percent ethanol and 90 percent gasoline) and E5 (a biofuel with five percent ethanol and 95 percent gasoline) gas sold in Finland.

VTT says that it conducted the study because many Finnish people frequently claimed that fuel consumption is significantly higher with E10 than with E5 thanks to ethanol's lower octane rating. The suspected increase in consumption has deterred many drivers from fueling with E10.

The VTT measurements show that the vehicles tested consumed an average of 10.30 liters of E10 per 100 kilometers, compared to 10.23 liters of E5 per 100 km. The difference was, on average, 0.07 liters in favor of E5, giving a meager 0.7 percent consumption increase when using E10. Now, for Americans, let's see this test conducted using our E10 and E15.

[Source: Green Car Congress]


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    • 1 Second Ago
  • 8 Comments
      Doug
      • 4 Years Ago
      "...many Finnish people frequently claimed that fuel consumption is significantly higher with E10 than with E5 thanks to ethanol's lower octane rating. " You might want to fact check that statement.
        Ziv
        • 4 Years Ago
        @Doug
        Ethanol has 76,000 BTU's per gallon vs. 116,000 BTU's per gallon for gasoline, but the octane in ethanol tends to be higher, so in a perfect world flex-fuel cars would increase the compression ratio to take advantage of that higher octane, but they don't appear to do so. So E85 will mean you will need 40% more E85 than you would need if you could buy pure gasoline with no ethanol. So ethanol has a lower energy density or energy content, not a lower octane.
      2 Wheeled Menace
      • 4 Years Ago
      Ethanol has just a bit over half the energy per gallon that gas does, so yup, the more you put in, the worse fuel economy you're going to get. Sure beats MTBE as a fuel additive though.
      • 4 Years Ago
      I'd love to find out who funded this study. My personal data is very different. My 2007 Dodge Ram with the Flex Fuel V8 had a lifetime average of about 17.5 mpg (over 85,000 miles) when I switched to E0 two months ago. Over the last 4011 miles, I'm averaging 19.69 mpg with the E0. My cost is about 3% over E10, but the mileage gains more than compensate.
      Anonimouse
      • 4 Years Ago
      I have kept MPG numbers for every tank that I have put in my car for over 46000 miles. My numbers show about 4% lower fuel economy using E10 compared to 100% gasoline. Do your own study and decide for yourself. Don't take anyone else's word for it when you don't have to. Due to subsidies, the cost may appear lower for E10 than 100% gasoline, but I am skeptical of the benefits of making ethanol from corn. Additionally, I saw E85 at a pump the other day and the price was almost the same as E10. This may be a local condition only and the remaining comments are based upon the local price. Cars that use E85 get much worse mileage than E10. So corn based ethanol is so smart that it will cost me more to get to where I have to go?
      Timo
      • 4 Years Ago
      It is not the difference between 95E5 and 95E10 it is between 98E5 and 95E10. With current Finland gasoline prices 98 is cheaper because consumption is less. VTT is researching wrong thing. When gas-companies started to sell 95E10 in Finland 95 price increased so much that it isn't competitive with 98 anymore. They cost nearly same now. Also I'm pretty confident that cars used in that study are new. With Finland zillion taxes related to cars our car base is pretty old. 10+ year old cars are very common. Nobody is willing to buy new cars when they cost something like twice what they cost in US for example. That is the result of "green party" having been in government. Less green cars. Stupid shortsighted idiots. Cars are necessity in here. Every other party is more green than green party. Luckily our government is now changing.
        Timo
        • 4 Years Ago
        @Timo
        Replying myself. Seems that Autobloggreen has few facts wrong in the text. Noticed that in the chart they have 98E5 and 95E10, text mentions 95E5 and 95E10. difference in price between 95 and 98 is about 3%. Study claims 1% difference (searched source). As expected VTT study is no real world study, but laboratory study. Based on several other sources real world numbers are much worse, including people driving so long distances before making decisions that differences between environments are filtered out. Not all cars obviously suffer from this phenomenon (as in VTT study shows Saab works well with just about any gasoline). VTT apparently had only few cars in the study, BMW, MB, Toyota, Citroen, VW etc common cars are missing from the study. I suspect result-driven selection of cars. Wouldn't be the first time VTT is making sponsored and biased study (to whoever pays the most).
        • 4 Years Ago
        @Timo
        Timo is right. A comparison should be between 95E5 and 95E10, not 98E5 and 95E10, if the objective is to compare E5 to E10. 98E5 has higher energy density than 95E5.