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Brooks Wilson's Economics Blog: Ethanol as a Gas Additive

Wednesday, December 16, 2009

Ethanol as a Gas Additive

My family and I drove to Johnson County in Kansas for Thanksgiving.  I filled up with a  E10 and 10% ethanol-90% gasoline blend before leaving expecting about a 3% decline in fuel mileage.  A gallon of ethanol contains about 70% of the energy contained in a gallon of gasoline and the government claims that 1.03 gallons of the ethanol blend is needed to replace every gallon of unblended gasoline.  I experienced much worse fuel mileage.  I tried to buy unblended gasoline for the return trip but failed.  For the first 325 miles my Sienna got 24.1 miles per gallon (mpg), and for the second 325 miles, 26.7 mpg.[1]  The E10 reduced my fuel mileage by 10.79%!  On the first half of the trip, I used 11.95 gallons of gasoline, and on the second, 11.98.  If the purpose of the E10 is to reduce oil consumption, it isn't working.  Perhaps it will keep the air cleaner, but I would require an explanation to be convinced.  After all, I am using the same amount of gasoline, and if the government claims of gasoline mileage are exaggerated, why not the environmental claims?[2]

I did a little research meaning that I did a Google search, read three articles and found one describing similar experiences.  The article, "Drivers avoiding ethanol additive," and  is written by the AP and published online by the  A Honda Accord driver experienced an even bigger decline in fuel economy (20%) than I.  
Corcoran said her husband's Honda Accord got a bit more than 30 mpg on “pure” gasoline versus 25 mpg on E10. Blakey, who lives in O'Fallon, Ill., soured on E10 after noticing a big drop in mileage in her family's 2002 LeSabre on a trip to visit her daughter in Ohio.
The writer interviewed Ron Lamberty, a vice president of the American Coalition for Ethanol, an industry group, who both sells and drinks Kools-Aid if my experience is typical.  He claims that,
...many vehicles running on E10 will experience a 3 to 4 percent drop in fuel efficiency, though some vehicles actually see a slight increase because of E10's higher octane rating.
The article paraphrases Lamberty as explaining that
...mileage critics are not taking a larger picture into account. Ethanol burns cleaner, creates jobs, is good for fuel-injection systems and - by reducing overall demand - reduces gasoline prices...Ethanol burns cleaner, creates jobs, is good for fuel-injection systems and - by reducing overall demand - reduces gasoline prices.
Lamberty earns a big uh-hu for the claim of reducing gasoline demand and therefore prices if my experience is common.  Gasoline prices will remain unchanged and corn prices will rise.  And what about those jobs?  Here Lamberty expresses make work bias, focusing on job creation rather than productivity.  We cold also create more jobs in the oil sector by simply pouring one gallon of gasoline in ten into the earth every time we fill up.  Think of the additional jobs needed to produce 10% more gasoline to compensate for the spilled gasoline and all the jobs that will be needed to clean the environment and the medical personnel needed to detoxify our bodies.  What a boost to the economy!  

[1]  To keep the math simple for the purpose of exposition, I assumed that the trip was evenly divided between the two fuels.  The first part of the trip, which used the ethanol blend was approximately 390 miles and the second part, 260 miles.  My vehicle got 24.10 mpg with the ethanol blend, and 27.35 mpg with gas.  I used .0373 gallons of gas per mile, not counting the ethanol, on the first half of the trip and only .0366 gallons per mile on the second.  I burned more gas with the ethanol blend than with just gas.  And the story gets slightly worse.  My tank completely empty when I filled up with unblended gas.   

[2]  The Clean Air Act Amendment of 1992 requires the use of oxygenated gasoline in areas with unhealthy levels of air pollution. 


  1. Are you serious? Where do you think jobs for additional gasoline would be located? NOT IN THE UNITED STATES! Ethanol is better for the enviornment and helping the economy. It's sticking money right back intot he U.S. instead of shipping it overseas. Ethanol does provide a lot of good jobs in which we seem to have quite a shortage of right now. So for a few miles you would rather send your money overseas?

  2. Anon. Thanks for the comment. I needed more space than that allowed in a comment, so I responded in a new post.

  3. You're assuming the only difference between your fuels was the ethanol content. Gas composition can vary quite drastically. I assume the research that has been done on this makes sure that they have consistent products. Was everything else consistent? Did you add or subtract weight from the vehicle? Speeds? Weather or temperature?

    Or maybe there's something goofy with your car. I believe that anecdotally this could happen from time to time, but what you're saying is not a claim that even the scientists opposed to ethanol production are claiming. That leads me to believe there's a factor that you've failed to realize.