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Monday, July 18, 2005

Biodiesel and Ethanol

Yesterday, AP writer Mark Johnson published an article based on a report by two university researchers which claims that both ethanol and biodiesel require more energy to produce than they actually deliver:
[R]esearchers at Cornell University and the University of California-Berkeley say it takes 29 percent more fossil energy to turn corn into ethanol than the amount of fuel the process produces. For switch grass, a warm weather perennial grass found in the Great Plains and eastern North America United States, it takes 45 percent more energy and for wood, 57 percent.

It takes 27 percent more energy to turn soybeans into biodiesel fuel and more than double the energy produced is needed to do the same to sunflower plants, the study found.

"Ethanol production in the United States does not benefit the nation's energy security, its agriculture, the economy, or the environment," according to the study by Cornell's David Pimentel and Berkeley's Tad Patzek. They conclude the country would be better off investing in solar, wind and hydrogen energy.

The researchers included such factors as the energy used in producing the crop, costs that were not used in other studies that supported ethanol production, said Pimentel.
Fortunately, I have access to online resources which allowed me to find the original article by Pimentel and Patzek. Pimentel and Patzek were VERY thorough in including "such factors." As far as growing soybeans are concerned, they seem to have assumed the use of the most energy-intensive American agricultural methods, using lots of fossil-fuel powered machinery, fossil-fuel derived fertilizers, herbicides and pesticides, and even "transport," which a footnote explains assumes that "machinery, fuel and seeds" were shipped an estimated 1000 km. And on the production of biodiesel from soybeans side of the story, the authors included massive amounts of energy for steam, space heat, direct heat, and electricity, ignoring the possibility that such energy could easily come from the sun or wind (and how much space heat would you need if your biodiesel plant were in Texas, or if it operated only in harvest season in Michigan or Illinois?). Even with these assumed extravagances, Pimentel and Patzek are able to show only an 8% energy loss for soy-based biodiesel after grudgingly admitting that extracting the oil from soybeans leaves commercially-valuable soy meal (they claim a 32% loss when ignoring the soy meal, although these numbers somehow becomes 27% in the abstract and hence the AP article).

The Cornell web site quotes Pimentel:
The United State desperately needs a liquid fuel replacement for oil in the near future, but producing ethanol or biodiesel from plant biomass is going down the wrong road, because you use more energy to produce these fuels than you get out from the combustion of these products.
While his research seems to show that it is certainly very possible to make biodiesel and ethanol at an energy loss, it really provides no basis for claiming that biofuels, especially biodiesel, are the "wrong road." Perhaps the authors have looked at this objectively, but their research numbers certainly seem to indicate finding a result to match a pre-determined conclusion.

Now, I have no doubt that biodiesel and especially ethanol proponents have been doing the same thing on the other side of the argument for years. Federal incentives for ethanol production are living monuments to the founding fathers' error in assigning two senators to each state. But I would conclude from Pimentel and Patzek's antagonistic report not that biofuels are the wrong road, but that done properly they may actually provide most of the liquid fuel we will need in the future. That won't be anywhere near the amount we currently use (being wasted on extravagances like shipping soybean seeds 1000 km, for example). But it may be enough to run the trains and ambulances and other vehicles that a sustainable yet somewhat modern economy will actually require.