I’m sure this post will provoke a couple of “don’t you have better things to do with your time” but, hey, we all need our hobbies and mine appears to be random biodiesel calculations at the moment. =) New fun fact regarding the fuel efficiency of coffee.
There was an announcement last week about a researcher in Brazil working on turning low quality coffee beans into biodiesel. In the press release, it says that “every 100 kilograms of coffee will produce roughly 9 kilograms of oil” and “a liter of biodiesel requires about 15% of a liter of ethanol”. So, what does that mean in terms of fuel efficiency of coffee bean biodiesel? Well, if you consult the always-handy Biodiesel Handbook and the always-handy Google, you find that the fatty acid profiles of coffee bean oil and cottonseed oil are pretty similar (source for coffee bean oil). Using Google again, we find that the density of cottonseed oil is 0.92 g/cm3 or 0.92 g/ml (source). So coffee bean oil has a density of about 7.67 lbs/gallon or 3.49 kg/gal. If 100 kilograms of coffee yields 9 kilograms of oil, that means 100 kilograms of coffee yields 2.58 gallons of coffee oil. And, if ethanol is 15% of the biodiesel by volume, you end up with 3.03 gallons of biodiesel from 100 kilograms of coffee. Now, from before, we know an average diesel engine gets about 30 miles to the gallon but biodiesel has about 10% worse fuel efficiency. So, 3.03 gallons of biodiesel takes you 81.9 miles (3.03 x 27). So, 100 kilograms of coffee gets you 81.9 miles and a diesel engine has a fuel efficiency of 0.82 miles per kilogram of coffee beans or 0.37 miles per pound of coffee beans (about 8x less than liposuction fat).
Now, if we take this one step further, 1 pound of coffee beans yields 10.8 pots of brewed coffee (source). So, another way to think about this is that a diesel engine has a fuel efficiency of 0.034 miles per pot of coffee.
Enjoy … and feel free to make fun of my hobby. =)
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3 comments:
You know, I'm a little disappointed in that. I would have thought coffee would give you way more mileage -- I mean, according to that, EAF only gets 0.09 miles per day on coffee. I would have thought he got much, much more.
Be able to drag my butt out of bed in the morning must be worth at least 1000-2000 miles, and that's only one cup of coffee. Plus, I think my heart would stop if I didn't get my daily coffee. How many miles is that worth?
Coffee definitely appears to be a much better fuel for people than for cars. =)
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