Can Biofuels Take Flight?

In February 2008, Virgin Atlantic Airways made aviation history by flying a Boeing 747 commercial jet run partially on biofuel from London to Amsterdam. To test how the plane would fare when powered with bio-stock in comparison with traditional kerosene jet fuel, Virgin Atlantic (VAA) erred on the side of caution and chose to power only one of the aircraft's four engines with biofuel - in this case, derived from coconut and babassu palm oils. With proper safety precautions in place, the Civil Aviation Authority, the U.K. equivalent of the Federal Aviation Administration, gave the flight its seal of approval. After much anticipation, the history-making 40-minute flight went off without a hitch; the engine running on coconuts performed as well as those burning traditional jet fuel.
The aviation industry's curiosity about this biofuel-powered flight was not unjustified: jet fuel must meet standards that no previous biofuel had met. The internationally accepted kerosene fuel, known as JetA, is ultrarefined and carefully engineered. (Inside the industry, it's referred to as "the champagne of fuel.") It can withstand temperature changes from 86 degrees Fahrenheit to minus 40 degrees. And it packs a tremendous amount of energy per drop, so planes flying long distances don't have to land to refuel. By comparison, early biofuels have been shown to gel at cold temperatures, which could clog jet engines.
Virgin Atlantic's tropical biofuel passed muster, but it took some 150,000 coconuts to help make 400 gallons of fuel for the relatively short flight. Considering that 38 billion gallons of fuel are consumed by the international aviation industry each year, coconuts are obviously not a sustainable alternative to JetA, says Sian Foster, sustainability manager at VAA. Still, she says, the flight made an important point: technology has progressed far enough to make an alternative jet engine fuel possible. That's just in time, since aviation is one of the fastest-growing branches of the transportation sector, with greenhouse gas emissions projected to double by 2030 because of increases in passenger volume. The environmental benefits of biofuels will be further enhanced when used in combination with lighter, more fuel-efficient jets, such as Boeing's 787, which features carbon fiber wings.
To jump-start the quest for a renewable alternative to JetA, nine international air carriers, including VAA, were recently joined by Boeing and NRDC to form the Sustainable Aviation Fuel Users Group (SAFUG). The group's research encompasses the environmental implications of alternative, plant-based fuel sources, including their carbon footprint, from planting through refining and combustion.
SAFUG is looking closely at jatropha and algae, two plants that have been to shown to produce more energy than first-generation biofuels such as those based on soybeans and corn oil. Jatropha, common in tropical countries, grows on nonarable land and nets some 150 gallons of oil per acre. (Corn produces 40 gallons of biofuel per acre, while soybeans produce 60.) Oil is extracted from the seed of this thorny plant and is then refined into biofuel.
Algae are the most common plant group on the planet, and conservative estimates suggest that their biomass can be converted into energy at a scale of 5,000 gallons of oil per acre. Algae are seen as the ideal energy source of the future but have yet to be grown on an industrial scale. As this energy sector develops, NRDC wants to make sure this potential fuel source is truly sustainable before it's brought to market, anticipating both the environmental benefits and damages that come with producing biofuels. The organization will have to work fast: both Boeing and VAA hope to have regular biofueled flights by 2012.