Let the Sun Set on Corn-Based Ethanol

January 18, 2007

Enthusiasm for corn-based ethanol is idiotic.

Reports published in 2004 and 2005 suggested that the energy output from corn ethanol was lower than the fossil energy required to produce the alternative fuel. This gut-wrenching conclusion arises from a complete analysis of the ethanol production cycle. After accounting for all of the petroleum products used for ethanol production processes (harvesting, pesticides, refining, shipping, etc), it turns out that burning gasoline in your car is more conservational than burning corn-based ethanol.

More recently, a new glimmer of hope was injected into the corn-based ethanol debate. A UC Berkeley team led by Prof. Alex Farrell reviewed several previous corn ethanol studies, revising apparently incorrect assumptions and outmoded data. The UC Berkeley paper concluded that current corn ethanol technologies are much less petroleum-intensive than gasoline. Corn ethanol seemed to be rising from the grave.

Then in 2006, the corn ethanol coffin was hammered shut again by Tiffany Groode at MIT. To determine the fossil fuel input per volume of ethanol, Groode used a probabilistic approach that accounted for variability in system inputs. Instead of a single answer, Groode’s result was a distribution. This study showed that all previous ethanol reports were essentially correct, but dissimilar system input assumptions yielded disagreeing results. Groode’s conclusion: there is a high probability that traveling a mile on ethanol uses about the same amount of energy as gasoline. However, the probabilistic nature of the study makes it impossible to state any conclusion with absolute certainty. According to Groode’s most optimistic numbers, the very best ethanol could do is provide a 1.5 X multiplier to the input fossil energy.

In an article published by the MIT News Office, Groode said that she views corn-based ethanol as a stepping-stone. “People can buy flexible-fuel vehicles right now and get used to the idea that ethanol or E85 works in their car. If ethanol is produced from a more environmentally friendly source in the future, we’ll be ready for it.”

Groode may think corn ethanol is a stepping stone, but I think it is a dangerous farce. If corn ethanol is almost certainly a break-even technology and possibly an energy sink, we have no business growing distillery-bound corn on land that could be used for something else. Why invest in ethanol distilleries and distribution infrastructure if there is a good chance that they won’t reduce our fossil fuel consumption?

The US has a nasty habit of becoming attached to investments and infrastructure that no longer make sense: the electrical grid, hard-wired telephones, 9-month school cycles, etc. By establishing corn-based ethanol infrastructure now, it will be difficult to let go when a better ethanol technology comes along. By embracing corn ethanol, we may be deepening and prolonging our addiction to fossil fuel instead of weaning ourselves from it.

Posted by Matthew Traum on January 18, 2007 | Comments (2)

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June 25, 2007

In response to: Let the Sun Set on Corn-Based Ethanol
aldr commented:

Wow! It is interesting how two different people can read the same report and come to different conclusions. I understood the report from MIT has having the opposite conclusion. The study concludes ethanol with co-product credits is more energy efficient than gasoline. With advances in technology it has the potential to be much more efficient.

February 2, 2007

In response to: Let the Sun Set on Corn-Based Ethanol
iolight commented:

I don''''t understand why you are essentially discounting the new studies. Pretty much everyone agrees that corn ethanol is not perfect, however it''''s a wash today in terms of efficiency. More importantly, improvements in processing (like conversion enzymes, see Novozyme) are working, so corn ethanol is becoming more and more efficient while buying us time, as the MIT professor points out, to go into other sources like switchblade grass. Your pessimism sounds unsubstantiated.

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