There were a couple of strange things about the Virgin Atlantic Boeing 747 that taxied out along one of London Heathrow's two main runways and took off into the bright sky late Sunday morning. First, there were only five people on board, while more than 100 watched intently from a nearby hangar. Second, the plane was the first commercial jet ever to fly on biofuel, a fuel produced from plant matter instead of petroleum or other fossil fuels. "This is the first stage on a journey towards renewable fuel," Virgin founder Richard Branson told reporters in the hangar shortly before takeoff, his voice drowned out every now and then by the roar of overhead planes. "It's the equivalent of those exciting first few steps of a baby."
As it happens, Virgin's eco-plane ran only one engine on the experimental fuel; the other three burned standard jet fuel. And the biofuel-powered engine was using a blend of conventional jet fuel and biofuel: 80/20 in favor of the regular stuff. In total, then, just 5% of the 49,000-lb (22,000 kg) fuel load consisted of the novelty: a special mix of coconut oil and oil from the Brazilian babassu plant, prepared by Seattle-based Imperium Renewables over the last 18 months and tested by General Electric Aviation in Ohio.
Even as environmental groups roundly pooh-poohed the flight as a publicity stunt, Virgin and its partners stressed that percentages weren't the point. The event was, the businesses claim, meant merely as a demonstration. "What we're proving today is that biofuel can be used for a plane," Branson told reporters. "Two years ago, people said it was absolutely impossible." Among the fears: that biofuel would freeze before a plane reached cruising altitude, or that it would require massive and costly changes to the aircraft or fueling systems to work at all. Those prognosticators were proved wrong. The fuel Virgin used Sunday required no equipment modifications at all; the plane flew to 25,000 feet (7,600 m) without incident; and the environmental benefits seem clear, at least once the fuel is loaded onto the plane. Internal company testing suggests the biofuel, when burned, releases just half the emissions of conventional jet fuel.
Still, there are no plans to make commercial air fleets run on coconuts. In fact, biofuel producers in general have had a tough couple of years. As food prices soar worldwide, people are growing ever more worried that biofuel production can drive up the prices of staple foods. Tens of thousands of Mexicans marched in January 2006, for example, to protest the rising price of corn, used in the U.S. to make ethanol. Virgin and partners claim that their airplane fuel is, as Branson says, "completely environmentally and socially sustainable." It's not made from staple-food crops or from crops that required deforestation. But even coconuts and babassu have their problems: the oil yield is just not that high. If a 747 could run on coconut oil alone, it would still take more than a dozen acres of crop to fill one plane.
Down the line, say Branson and Imperium Renewables CEO John Plaza, biofuel producers are more interested in jatropha, a thorny plant that grows well on non-agricultural land in Latin America and Africa. They're also interested in farming algae, which Branson calls "the jet fuel of the future." Development of those feedstocks does look promising, but commercial mass production is still years off. And getting regulatory approval for the new jet fuel could take several years as well. So if biofuel ever takes off in aviation, it will likely be a decade before it has any noticeable impact on industry emissions.
Is it worth the effort? Some critics like Greenpeace activists who breached Heathrow security Monday to protest the airport's proposed third runway argue it makes more sense simply to fly less. Others argue there are bigger, more realistic environmental gains to be made by building more efficient airplanes. Boeing's 787 Dreamliner, once it's finally shipped out to its buyers, is expected to burn 20% less fuel than similar-sized planes and that plane will be in commercial use in just a few months. As priorities go in aviation sustainability, "Right now [biofuel] will be very low," Virgin Atlantic CEO Steve Ridgway tells TIME. But with fears that the days of oil are numbered, it only makes sense that a business would try to diversify its raw materials in the long term. And cutting overall industry emissions will be no easy task if demand for flights continues to grow. "We cannot be Luddites and turn the clock back," Ridgway says.
Just before 12:30 at Heathrow, Virgin Atlantic's 747 touched down in Amsterdam, finishing off the event without a hiccup which is more than could be said for Branson himself. For kicks, the mogul had drunk a sample of his firm's coconut oil and babassu oil jet-fuel blend. "My God that was horrible," he told reporters afterward. "I've been burping ever since." Now that, without a doubt, is a publicity stunt.