First Passenger Flight Powered by Biofuel--But Are the Petroleum Alternatives Ready to Takeoff?

Dec 3, 2009 - David Biello - Scientific American

Test flight results have been good, but questions remain whether jet biofuel be produced in large quantities--and sustainably

PASSGENGER BIOJET: KLM flew the first flight with passengers partially powered by jet fuel made from plants. KLM / Allard de Witte

Dutch airline KLM has completed a fifth jet biofuel test flight-and the first with passengers other than flight crew. Using a 50-50 blend of regular jet fuel and biofuel refined from camelina oil in one of its four engines, the flight carried 42 "observers" for an hour on November 23 from Amsterdam's Schiphol Airport, enough to fill business class, according to chemist Jennifer Holmgren, who was on board.

"The civil aviation authority in the Netherlands said we've seen enough of this fuel that I'm comfortable putting people on it," says Holmgren, who works for refiner UOP, a division of Honeywell International. "We went from people saying we couldn't do this three years ago, to making a drop-in sustainable aviation fuel today."

The test flights are part of an aviation industry plan to derive 1 percent of jet fuel from petroleum alternatives by 2015, or roughly 600 million gallons a year. Already, biofuel producers are gearing up production. Camelina grower Sustainable Oils-which provided the camelina oil to make the 1,000 gallons of jet fuel needed for the KLM flight-plans to cover more than 20,000 hectares in Montana with the weedy relative of canola, enough to deliver some 9.5 million liters of raw oil. And algae grower Solazyme recently won a contract to supply more than 75,500 liters of fuel derived from algae oil to the U.S. Navy, which would be a first for the industry.

Testing and certification procedures under American Society for Testing and Materials International (ASTM) are underway, as well, with the jet biofuel to be included under the specification for synthetic paraffinic (waxy) kerosenes approved earlier this year for alternative fuels derived from coal. "It's been in practice for 15 years in South Africa, this is not new," notes Darrin Morgan, director of sustainable biofuels strategy at Boeing. "We expect that whole process [of certification] to be done sometime in 2010."

That does not mean airlines will be flying on half and half blends of bio-based and conventional jet fuel as soon as next year, however, largely because there will not be much of the mixture available, even if it is certified by ASTM and, ultimately, the Federal Aviation Administration. Large-scale refining of such bio-based oil has yet to result in any dedicated facilities. Instead, batches for such test flights or military contracts are processed over months individually by UOP at a Houston facility.

"We've made 40,000 gallons," Holmgren says, and notes that existing refineries can be modified to make the fuel. "We're modifying the facility further to improve the throughput." That's because the core of making jet biofuel is much the same as the core of making conventional fuel: hydroprocessing, or the adding of hydrogen to existing hydrocarbons in order to remove oxygen and other impurities as well as build the right molecule. All the bio-version lacks are the aromatics-specific volatile hydrocarbon rings that are necessary to swell shut seals within current aircraft engines, hence the need to blend it with conventional fuel.

But for biofuels to really take flight-or at least achieve the global aviation fuel use goal of at least 1 percent-a minimum of five facilities capable of churning out 100 million gallons or more would have to be built.

"Building a plant is a couple of years out," Holmgren says. "Three to five years is a reasonable time frame."

There is also ongoing controversy surrounding some of the plants used to make the jet biofuel, which include not only camelina and algae but also Jatropha, among others. Jatropha, for example, largely grown in East Africa and India to date, has proved to require more water than initially anticipated, a problem in areas where fresh water is a scarce resource. But Boeing's Morgan argues that Jatropha can make sense where fresh water is ubiquitous and a problem for soil erosion, such as Madagascar and Haiti. "If Jatropha is consuming a lot of water, that's exactly what you want it to do because that prevents further soil erosion," he says, noting that a "best practices" lifecycle analysis for Jatropha will be available from Yale University in 2010, along with a study of halophytes-plants that can tolerate salt, which have not been used to make biofuel to date. "It's fact finding for what are the best ways to do these things."

A similar study by Michigan Technological University sponsored by UOP found that jet biofuel from camelina could reduce emissions of greenhouse gases by as much as 84 percent and be grown in rotation with wheat crops. Of course, fuels from such sources also cost more than conventional jet fuel. "It's safe to say 50 cents to a dollar per gallon for the processing step, including transportation," Morgan says. "That's not in the future, that's now. It's just a matter of getting those plants going."

He adds: "As soon as it's certified, I wouldn't be surprised if people and airlines want to fly on it."

The first group to explore producing jet biofuel from such a facility was also announced by KLM after the flight last week-SkyEnergy will be a joint venture for the Dutch airline with North Sea Petroleum and Spring Associates. "This is a path to commercialization," Holmgren says, "which is what all these test flights have been about."