Airplanes of the future may not look like something out of the "Jetsons" or "Star Trek," but they'll be powered by anything from vegetable oil to algae.
"We can't put in long extension chords for electric powered airplanes," says Bill Glover, environmental strategy chief at Boeing . "We've got to be able to use liquid fuel with very high energy content."
The alternative jet fuel sector right now is a competitive one with various technologies under development and even with an economic slowdown and lower oil prices, airlines, engine makers, chemical companies and governments are working quickly to address supply needs.
"It's not going to be a single winner or loser," says Lourdes Maurice, chief scientist and technical advisor with the Federal Aviation Administration's Office of Environment and Energy.
Saving the Environment & Bottom Lines
As with other industries, the airline business has more than enough reasons to pursue viable alternatives.
Fuel became the largest component of operating costs for U.S. airlines in 2006, part of a relentless price spiral in energy prices that challenged the profitability of the industry. In addition to volatile oil prices, possible caps on carbon emissions have also prompted the sector to invest hundreds of millions of dollars into developing a more secure and affordable energy source.
That said, price competitiveness remains a key criteria.
"This fuel alternative would work if it's equal to or below what airlines are paying today," says Julius Maldutis, airline analyst and president of Aviation Dynamics. "At this stage of the game, I don't know what that cost is gonna look like."
In the near term, estimates put the cost of biofuels at $80-100 a barrel, says Boeing's Glover, though that figure could slide to $40 over time. That's not dissimilar to oil prices, which have ranged between $32 and a record high of $147 in the past year.
Exploring Different Technologies
As the aviation community develops alternatives, the idea is to alter the fuel not the aircraft.
"If you look at aircraft, they are in essence long-life assets; they can be around for 15-30 years," says Maurice. "And if you can have a product that is in essence a drop-in, you get the benefit very rapidly."
Right now, these fuels fall into two categories—organic and synthetic—and are created through one of two processes.
Thus far, only one fuel—a synthetic-based one manufactured in South Africa—has been approved by the international standards organization, ASTM.
The Fischer Tropsch process, developed during World War II when the allies cut off Germany's oil supplies, uses coal, natural gas or biomass, which is chemically converted into petroleum substitutes.
"In the near term as far as getting initial capacity up, Fischer Tropsch is more practical," says Maurice. "In the longer-term, the more attractive option from an environmental perspective would be hydrogenation."
Fuels developed from plants (using the hydrogenation process) have the same carbon emissions as kerosene, but the environmental benefit comes when they are grown.
"It's a zero add of carbon dioxide," says Nancy Young, vice president of environmental affairs at the ATA. "It's just recycling it."
In February 2008, Virgin Atlantic became the first airline to fly on a biofuel, which was composed of babassu and coconut oils. Later that year, Air New Zealand tested a 50-50 mix of fuel made from the oil of jatropha plants and Jet A1 fuel. Continental Airlines completed the third test flight using a 5-50 bend of conventional fuel and oil from jatropha plants and algae.
"The biofuel performed exactly like the jet fuel," says Leah Raney, managing director of global environmental affairs at Continental. "We wouldn't have to change our engines; we wouldn't have to change any of our systems in the aircraft."
Most recently, Japan Airlines tested an equal-parts mix of renewable fuel derived from camelina and kerosene. In 2010, JetBlue will team up with Airbus, a subsidiary of EADS , Honeywell UOP and International Aero Engines to test biofuels made from jatropha, algae and other feedstocks.
Ultimately, geography will play an important factor in what plants are grown to create fuel. Camelina, a rotation crop in the northern United States and Australia, is complimentary to wheat farming and a likely contender for US aviation. Similarly, jatropha, a shrub that grows well in heat will likely be cultivated in India or Africa. Long-term, biofuels will come from hallophypes, plants that grow in salty conditions, or algae, which appears to deliver high oil yields.
Producing oil from plants for aviation, however, faces a supply-and-demand challenge, says Jennifer Holmgren, head of the Renewable Energy and Chemicals business at UOP. Unless there's demand for a feedstock, farmers won't plant it. And, unless they are mass-produced, biofuels are too costly.
"You're sort of in a Catch 22, as you try to develop the industry," she says.
Safety Weighs Heavily On Approval
The greatest challenge to bringing alternative fuels to market may be convincing investors.
"We need standardization to give confidence to investors," says Christian Dumas, head of environmental programs at Airbus. "It's more than a technical test itself, it's more a demonstration to the community that, yes, it works."
While fuels produced by Fischer Tropsch are being reviewed this year, biofuels derived from camelina and jatropha are scheduled for 2010-2012. If all goes well, aviation is betting that biofuels could power commercial airplanes as early as 2012.
Ultimately, safety will take the front seat in the certification process. Although domestic aviation currently produces 2 percent of greenhouse gas emissions compared to some 27-28 percent for ground transport, according to the ATA, the industry faces more stringent safety hurdles.
"You cannot pull off the side of the road in the sky," says Maurice.