As Jet Fuel Prices Soar, a Green Option Nears the Runway

Aviation is making an important step in breaking free of its petroleum dependence through biofuel.

In March 2011, a U.S. Air Force F-22 Raptor powered by a 50-50 blend of renewable and petroleum jet fuel flew at supersonic speed from Edwards Air Force Base in California. The important test helped prove the fuel's viability.

Photograph courtesy Kevin North, US Air Force

The ethanol that is typically used in cars—fuel alcohol refined from grain or sugar cane—would not work in aviation, at least with today's jet engines, because its energy density (the power it packs per gallon or liter) is too low. But numerous start-up companies around the world have been working with a very different fuel derived from oils that have been extracted from plants, animal fat, or grease. The oils are treated with hydrogen to produce HRJ, synthetic kerosene that is chemically the same as jet fuel. Only carbon dating would reveal that it is not made from fossil fuel.


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