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Ethanol: Miracle Fuel, or Not?

Ethanol as a fuel may be carbon neutral, but offers few other benefits.  

by Brian Dunning

Filed under Environment, General Science

Skeptoid Podcast #51
June 25, 2007
Podcast transcript | Download | Subscribe
Also available in Chinese



Once again I'm going to be politically incorrect and point my skeptical eye at something that comes from nature: Ethanol. Ethanol, largely produced from corn in the United States but also able to be produced from a variety of other organic substances, is increasingly being offered as the alternative fuel of choice for drivers.

I'd like to start off by beating my detractors to the punch. Since I'm going to criticize ethanol in this episode, I'm going to be called all sorts of names, but mainly I'm going to be accused of being on the payroll of the big oil companies who are afraid of losing business to nature's wonder fuel. So, yes, I'm a corporate stooge, and I'm secretly getting big bucks under the table for doing this podcast. OK? I get it. Save your breath.

There's a tendency when discussing alternative fuels for cars to only look at the tank-to-wheel part of the equation. Tank-to-wheel refers to the part of the fuel cycle involving the burning of the fuel in the engine to drive the wheels. Pump-to-tank refers to the infrastructure needed to deliver the fuel to your car. Well-to-pump refers to the whole process of creating the fuel, regardless of where it comes from, and delivering it to your local gas station. Well-to-wheel is the term that covers the entire process, from the original drilling of the oil to the rubber meeting the road. Whenever you're discussing an alternative fuel, you should always consider all these parts of the process, especially the overall well-to-wheel view. For example, hydrogen is fantastic when you only consider the tank-to-wheel portion. Unfortunately creating the hydrogen in the first place, during the well-to-pump stage, is expensive and generally a net loss of energy; and the infrastructure to deliver the hydrogen to your car in the pump-to-tank stage is non-existent.

Ethanol's major problems come in its well-to-pump phase. The University of Minnesota has concluded that if we converted all the corn we're already growing into ethanol, it would meet only 12% of our gasoline demand. Plus, we're already using the corn we're already growing, so we need to plant more corn to make ethanol. This means more fertilizer, more pesticides, and more International Harvesters. All of those things use fossil fuels, produce waste, and increase greenhouse gases. Growing more corn takes more water, usually in areas where everyone's already fighting over water rights. In Brazil they make ethanol from sugar instead of corn, which makes their equation work better because they have a natural overabundance of sugarcane. Ethanol cannot be transported in pipelines, because even with the best state-of-the-art pipeline technology, there is always water or other contaminants in pipelines and ethanol absorbs water — that's why you can make a scotch & soda. But it's no longer usable as fuel when this happens. Ethanol must be delivered by truck, which is the least energy-efficient way we have to transport liquids, or by rail car. Estimates vary depending upon which lobbying agency you ask, but the well-to-pump stage of ethanol production ranges from 31% efficiency to -200% efficiency. That worst estimate means that you had to burn three gallons of fossil fuel to put one gallon of ethanol into the gas pump, a net loss of two gallons worth of energy.

The best part about ethanol is pump-to-tank. Since it sits in the the same tanks and uses the same pumps at your gas station, there are no changes needed and no added costs.

And now it's time to deal with the biggest elephant in the room: As a fuel, ethanol really sucks. Ethanol's tank-to-wheel performance is abysmal. Its energy content is only about two thirds that of gasoline — 68% of the calorific content, to be exact. If you fill your tank with ethanol, you'll only get two thirds as far as you would with gasoline. To go the same distance, you need to burn more ethanol. Lots more. Let's say you have an average car that gets 25 mpg on gasoline. One day you decide to be environmentally friendly and you fill your tank with E10 (10% ethanol, 90% gasoline) instead. You'll get 24 mpg, a difference which you probably wouldn't notice. But let's say that next week you go down the street to where they sell E85 (85% ethanol, 15% gasoline). That same car is now only going to give you 18 mpg. That's a big drop from 25. Please, if you're going to use E85 on the premise of helping the environment, take the trouble to look up the numbers, and then decide if this is the best way to meet your goal. Don't just trust that because the oil companies make E85 available that it's automatically good. You will need to burn 137% as much E85 to go the same distance as you would on gasoline.

So why is ethanol so popular? Why does the Indy Racing League use it? Is it to reduce our dependence on oil from the Middle East? Hmmm, since only a small minority of our oil comes from the Middle East, that doesn't seem like it could be the whole reason.

I'd like to relate a short personal story that I think reflects a lot of the pro-ethanol support. A few years ago I went to my 20th high school reunion, and while there I talked with a former classmate whose job was to lobby cities and other fleet operators to switch to ethanol burning buses and cars. By chance I'd just read an article discussing these well-to-wheel ratios, and asked her about it. Before the sentence was halfway out of my mouth, she saw it coming and put up a hand to silence me; and then flew off the handle on a rabid anti-government, anti-American, anti-Western tirade about how capitalism is the cause of all famine and wars, that anyone who earns over $40,000 a year should be taxed over 100%, and that corporations are not defined in the Constitution and are thus illegal. Now, obviously it's a straw man argument for me to bring this up, as nothing she had to say was coherent or even relevant to the topic of ethanol, but I did find it interesting that these were the motivations of at least one professional ethanol lobbyist. I do not believe that she even understood the term well-to-wheel.

But there is more refined support for ethanol out there. Much of the real reason that political candidates are on its bandwagon is economic. Ethanol can be produced more cheaply than gasoline, it's subsidized by the federal government at 51¢ per gallon, and it's exempt from the federal gasoline tax. It makes more financial sense for oil companies to sell ethanol when they can. Ethanol's popularity has little to do with environmental friendliness or improved fuel economy, and more to do with economics and square-state politics. Next time you hear Mitt Romney or Hilary Clinton espousing the production of ethanol, listen to hear if you're being given the whole story, or just another political sound bite.

Bottom line: Keep working on true next generation fuel and power systems. Don't waste time, energy, and money on ethanol.

By Brian Dunning

Please contact us with any corrections or feedback.


Cite this article:
Dunning, B. "Ethanol: Miracle Fuel, or Not?" Skeptoid Podcast. Skeptoid Media, 25 Jun 2007. Web. 20 Jul 2017. <>


References & Further Reading

Gura, Trisha. "Driving Biofuels from Field to Fuel Tank." Cell. 10 Jul. 2009, Volume 138, Number 1: 9-12.

Patzek, Tad W., Anti, S.M., Campos, R., Ha, K.W., Lee, J., Li, B., Padnick, J., Yee, S.A. "Ethanol from corn: Clean renewable fuel for the future, or drain on our resources and pockets?" Environment Development & Sustainability. 1 Sep. 2005, Volume 7, Number 3: 319-336.

Petrolia, Daniel Ryan. "The economics of harvesting and transporting corn stover for conversion to fuel ethanol: A case study for Minnesota." Biomass & Bioenergy. 1 Jul. 2008, Volume 32, Number 7: 603-612.

Pimentel, D., Marklein, A., Toth, M., Karpoff, M., Paul, G., McCormack, R., Kyriazis, J., Krueger, T. "Food versus biofuels: environmental and economic costs." Human Ecology. 1 Feb. 2009, Volume 37, Number 1: 1-12.

Sanhueza, Eugenio. "Agroethanol: An Environmentally Friendly Fuel?" Interciencia. 1 Feb. 2009, Volume 34, Number 2: 106-112.

Tao, Ling, Aden, Andy. "The economics of current and future biofuels." In Vitro Cellular & Developmental Biology - Plant. 1 Jun. 2009, Volume 45, Number 3: 199-217.


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