The aviation industry has turned its attention toward biofuel as an alternative or additive to jet fuel, no doubt to cut greenhouse gas emissions, but also to address jet fuel prices that are soaring about as high as the planes they power. It might seem like a foregone conclusion that the adoption of biofuel use would represent a move in the right direction-and we’ve certainly seen interest displayed by both commercial airlines and the military-but a study conducted by MIT researchers indicates that, depending on how a biofuel is produced, it isn’t necessarily the greenest option.

The MIT researchers say that a biofuel’s origins have to be factored in to determine just how green it is or isn’t.  One example pointed out in a report about the study shows that if a fuel is made from palm oil grown in a clear-cut rainforest, then conventional fossil fuels could actually be the “greener” choice.

image via U.S. Air Force

James Hileman was the principle research engineer involved in the study. He said that technologies that look promising can also result in high emissions, if done improperly. “You can’t simply say a biofuel is good or bad — it depends on how it’s produced and processed, and that’s part of the debate that hasn’t been brought forward,” said Hileman.

Hileman, along with team members Russell Stratton and Hsin Min Wong, took what they call a “well to wake” approach to analyzing a bio-fuels life-cycle from acquiring the biomass to transporting it to converting it to fuel and ending with combustion. Hileman points out that all of those processes require energy, which results in CO2 emissions.

Through the study, the team determined that emissions would vary a great deal depending on the sort of land that was used to grow a biofuel’s feedstock, be it soy, palm or rapeseed. For example, it was determined that biofuels created from palm oil emitted 55 times more carbon dioxide if the palm oil came from a converted rainforest plantation  versus a previously cleared area. The team stresses that, depending on the type of land used, biofuels could ultimately emit 10 times more carbon dioxide than conventional fuel.

The study, which was funded by the Federal Aviation Administration and Air Force Research Labs, serves to show the aviation industry that a biofuel’s feedstock source and type are major factors in determining how beneficial a biofuel actually is.

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