Ethanol Efficiency
The news has recently contained a large number of articles discussing the energy efficiency of ethanol based fuels. There have previously been many critics of ethanol fuel, claiming that the process of creating ethanol consumed more energy than was gained by the alternative fuel itself.
This is a very tricky question. At the most direct and simplistic level, it's true. The production of ethanol as fuel, using traditional methods, uses more energy than the use of ethanol as fuel can create. I had to phrase that statement very carefully to ensure that it would be true, however! If the fuel is created - from sowing to processing using traditional equipment, operating using standard fuels, and no other products are created in the process, then the overall energy quotient is wasteful.
But that's not the case. Alex Farrell, an assistant professor at the Energy and Resources Group at the University of California at Berkeley, was the lead author for a paper recently published in "Science" which combed through the numerous studies of ethanol efficiency and attempted to reconcile their disparate findings.
Professor Farrell was interviewed by Andrew Leonard, of Salon.com. In his resulting article, "Bring on the biofuels", he discusses the biggest issue at stake in this reconciliation - setting the system boundaries. To quote:
Which means, basically, figuring out what's inside the system, and what's outside. "For example," says Farrell, "when examining the system of ethanol production, most people think that the fossil fuels consumed in the tractors on the farm are inside the system. But what about the factory that made the farm machinery?"
What Farrell and his team determined was that most studies which reached the conclusion that ethanol production lost energy had neglected to take into consideration the production of corn gluten feed, corn oil, and other related products which are also created during the overal cycle of fuel production. When these products are included, the net energy efficiency is positive!
What does this tell us about the potential of ethanol as an alternative fuel? First, that it can only be an effective solution with careful regulation. The life cycle of the product needs to be controlled from the ground up. If the source vegetables are grown organically, and transported using vehicles running on alternative fuel, and all byproducts are used, then the fuel can be highly energy efficient.
What's next for ethanol? New methods are being investigated involving cellulosic technology to allow the use of the woody parts of plants, but is currently too expensive a process to be economically viable.
Relevant Links:
- Biofuel Analysis Meta-model used in Study
- Science Magazine (Subscription required)
- Ethanol could reduce fossil fuel need: study (Yahoo.com)
- Bring on the biofuels - Salon.com
Updated by Joe Dolson on 24 August, 2009
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