10 percent Ethanol? Why not 20%?


Photo courtesy of anemergencystop at Flickr.com.

Last week, Congress passed a new law promoting Ethanol use. This will likely accelerate the spread of Ethanol from the heartland to fuel pumps nationwide. If you look carefully at your gas station, you may see a sign that says “This fuel contains up to 10% Ethanol.”

This low concentration of ethanol was chosen to prevent damage to cars that aren’t designed for ethanol. Very few cars on the road today are flex fuel vehicles, but all cars can use a 10% blend of ethanol without damage. At 10% concentrations, ethanol can reduce greenhouse gas emissions by 18-29%. Ethanol also cleans up other emissions from the tailpipe – engines burning ethanol release fewer smog causing compounds, less heavy metal, and fewer particulates.

One of the big concerns with ethanol is that it has a lower energy density than gasoline – which means that you get less mileage per gallon. A gallon of ethanol only has about 65% as much energy as a gallon of 88 octane gasoline. This begs the question – if you have to burn more ethanol to get the same performance, does ethanol still have a positive effect on the environment?



Well, an experiment performed by the University of North Dakota Energy and Environmental Research Center and the Minnesota Center for Automotive Research yielded some surprising results. Their results suggest that 20-30% concentrations of ethanol may improve fuel efficiency even compared to regular gasoline! If future tests confirm these results, it wont be long before we see pumps that offer 20% and 30% ethanol options.


Photo courtesy of Alan Gage at Flickr.com.

ps: There’s an urban legend floating around that ethanol takes more energy to produce than it supplies. According to some scientists this may have been true when the technology was less developed, but it isn’t true today. (Link goes to PDF file.) Also, some of the non-renewable products that are used (coal and natural gas) have domestic sources.



We estimate that on an energy basis, only 0.13 BTU of petroleum are used to produce a BTU of ethanol. Since the root of our short -term energy problem is related to liquid fuels, ethanol should be viewed as an extremely effective way to convert natural gas and coal into liquid fuel energy.



John Gleason July 3, 2008 at 1:27 pm

According to you: “ps: There’s an urban legend floating around that ethanol takes more energy to produce than it supplies. According to some scientists this may have been true when the technology was less developed, but it isn’t true today.”
Ok, Operative work is “some” scientists. Let’s get specific: Ethanol from corn has a lousy energy balance. Basically takes as much energy (or $$ they are really are equivalent)to produce it as it produces—on a life cycle basis. This according to informal conversation with scientist at the National Renewable Energy Lab.
Lets use a little common sense, too. Do we need to be taking food out of the food chain? I think not. The plus is that Ethanol from waste (agricultural) products shows alot more promise.
New topic. the place we are missing the boat in his country is Hydroelectric Power: Every darned town and and municipality that has a river or stream, can extract electrictty via low head/low flow turbines. The technology has been around for decades. These are low maintenance, and NO fuel cost systems. Surely this apporach could cover some fraction of our total energy demand. Gut feeling is as much as 15 or 20 percent. Has anybody ever looked at what fraction is possible?

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