Food or Fuel? Biofuels Inefficient, Study Suggests
An exhaustive study of 17 years’ worth of data on the use of productive farmland came to the following conclusion, according to one of the Michigan State University researchers:
“It’s 36 percent more efficient to grow grain for food than for fuel…
The ideal is to grow corn for food, then leave half the leftover stalks and leaves on the field for soil conservation and produce cellulosic ethanol with the other half.”
Given the large amount of noise around Washington about biofuels, much of which emanates from the direction of the corn lobby, these results are highly pertinent.
In today’s issue of Environmental Science and Technology (subscription required), the researchers published their findings based on 1989 to 2007 energy balance data from the W.K. Kellogg Long Term Ecological Research site in northeast Michigan. They looked at wheat, soybeans, and corn rotations under four management systems: conventional tillage, no-till, low chemical input and organic. They also examined a fifth system, alfalfa, which is can be used for cattle feed or biofuel. Alfalfa is a continuous forage crop replanted every 5-6 years following a grain crop break year. For all the different combinations, they measured the energy inputs and outputs of using the plants for food or biofuels.
If that seems a little complex, here is the researchers’ pithy conclusion: “For each system, the average energy output for food was always greater than that for fuel.”
They found that the overall energy efficiency is greatest for no-till management, because even though tilling yields higher energy outputs, it requires far greater inputs, mostly in the form of tractor fuel.
Also, “The use of grain crops for biofuel production resulted in 30-40% lower net energy gain than when the crops were used for food production. Alfalfa, on the other hand, yielded more energy when used as a fuel than as food owing to a lower livestock than fuel conversion factor: before alfalfa energy is available for food it must be converted to livestock energy.”
As we consider the best portfolio of approaches to reducing oil dependence, it is important to keep in mind that objective analyses have consistently shown that producing biofuels from food crops is simply not the answer. In addition to low energy efficiency, they are also highly water intensive, emit as much or more greenhouse gases than conventional fuels, and cannot be produced in quantities great enough to meaningfully impact our import dependence in the long term. Many experts believe that meeting the Energy Independence and Security Act of 2007’s requirement that 22 percent of transportation fuels be biofuels by 2022 is simply impossible without a major technological breakthrough.
Indeed, we should be focusing research on algae and cellulosic sources of biofuels, which may in fact prove to be economical and energy efficient. We should also consider diverting existing biofuel subsidies to supporting an option that can actually eliminate oil dependence in the long term – electrification of the light duty fleet.