Virgin Atlantic became the first commercial airplane operator to fly a plane powered partially by palm tree oil this week. In a short but historic flight, one of the company's Boeing 747-400s flew more than 200 miles (320 kilometers) from London Heathrow Airport to Schiphol Airport in Amsterdam, reaching a peak altitude of 25,000 feet (7,600 meters) during the 40-minute flight, with one of its four engines burning a blend of 20 percent coconut and babassu oils mixed with regular petroleum-based jet fuel.
"This pioneering flight will enable those of us who are serious about reducing our carbon emissions to go on developing the fuels of the future," Sir Richard Branson, president of Virgin Atlantic, said in a statement.
Unfortunately, that low-carbon fuel of the future is not likely to be the blend that performed well here. The reason: such biofuel may end up causing rather than curing climate change, according to recent studies. In addition, fuel from the world's limited supply of coconuts could drive up the price of the cooking oil as well as lead to further clearing of endangered rainforests in Southeast Asia for palm plantation expansion. And though the babassu palm grows wild in Brazil--not unlike switchgrass, a native perennial grass that might be used for ethanol in North America--there may not be enough of it to slake much of commercial aviation's thirst for fuel.
Regardless, the nut-generated biodiesel did not gum up the unmodified engine (biodiesel can gel when exposed to the low temperatures found at high altitude) or impair its smooth functioning. Technicians from Virgin Atlantic, Boeing, GE Aviation (maker of the engine) and fuel provider Imperium Renewables now plan to analyze data collected during the flight to assess the engine's performance and pollution emissions.
Air New Zealand will test a Boeing 747 (this one powered by Rolls-Royce engines) using biofuels in coming months--and more demonstrations may follow. The Virgin Atlantic flight "is just to prove to industry that you can make fuel that has these cold-flow properties," (does not congeal at lower temperatures), says David Daggett, Boeing's technology leader for energy and emissions. "The second [test] will be to look more at sustainability issues and second-generation feedstocks."
Virgin's flight follows in the jet wash of the U.S. Air Force, Airbus and BioJet 1. Both the Air Force in December and Airbus earlier this month completed flights powered by synfuel--liquid jet fuel made from coal or natural gas. Last October, BioJet 1--a 1968 Czechoslovakian L-29 fighter jet--reached around 17,000 feet (5,200 meters) on 100 percent biodiesel during a test flight in Reno, Nev. Florida-based Green Flight International plans to fly the old jet--chosen because it has fuel-line heaters to keep the biodiesel from gelling--more than 2,000 miles (3,200 kilometers) from Reno to Orlando, Fla., later this year, pending U.S. Federal Aviation Administration (FAA) approval.
The FAA has already approved at least one biofuel--ethanol--as an alternative fuel for two types of aircraft and engines, including the Piper Pawnee powered by Lycoming IO-540 engines. At least 1,000 crop dusters in Brazil have already logged "over 650,000 hours in spray operation on 100 percent ethanol," says Max Shauck, director of the Baylor Institute for Air Science.
But ethanol will not work for the larger jumbo jets in commercial aviation because it does not pack enough power per gallon. Sir Branson ultimately hopes to use algae to produce the energy-dense oil needed to fly them. The microscopic plant can produce 60 percent of its weight as oil and can be grown in dirty freshwater or even in the oceans, according to systems engineer Ron Pate at Sandia National Laboratories in Albuquerque, N.M., who has been analyzing its fuel power potential.
As Boeing's Daggett says: "There are still a lot of hurdles to overcome, but 10 to 20 years is a reasonable time frame for production of biofuels from algae."