Alternative Jet Fuels: The Reality Comes Closer

On Feb. 1 Airbus flew this A380 from Filton, England, to its main facility at Toulouse, using a blend of regular jet fuel and synthetic fuel made from natural gas using the gas-to-liquid process. Credit: Airbus S.A.S.

The aviation industry has dreamed of using alternative fuels since the energy crisis of the 1970s made petroleum-derived jet fuel pricier and dicier, but alternatives have never come close to taking off.

Now, driven by the sky-high price of oil, political instability in oil-producing countries and accelerating concern about global warming, an unusual combination of airlines, aircraft manufacturers, engine-makers and aviation industry groups is moving on multiple fronts to make the widespread, practical use of alternative fuels an everyday reality.

Obstacles

But many obstacles remain to be overcome before that can happen, experts say.

New fuels must be high in energy, safe to use and work well in sub-zero temperatures at high altitudes. They also must be cost-efficient to make and buy, be suitable for production in huge quantities and in ways that are environmentally sustainable, and they must burn clean.

It would also help a lot if the fuel of the future could be introduced in aircraft right now — blended with conventional kerosene jet fuel at first, and used as the sole source of power later on.

One big, overriding question looms: Exactly which alternative fuel is the best candidate to replace the jet fuel that has kept aircraft aloft for decades? There are many candidates, and each is getting its 15 minutes of fame.

One of the most promising potential fuels is gas-to-liquid synthetic fuel. GTL is made by converting natural gas, coal and other sources to a kerosene-like liquid. One advantage of GTL is that it does not produce polluting sulfur emissions.

GTL was judged to have encouraging potential after a test conducted on Feb. 1 by Airbus, when the aircraft manufacturing giant flew an A380 superjumbo from Filton, England to Toulouse, France, on a blend of conventional jet fuel and GTL.

Fuel cells for secondary power

Another alternative was trialed on Feb. 20, also by Airbus, and also found to have potential. On this flight Airbus flew an A320 with the help of a fuel-cell system it developed with Michelin. The fuel cell, used for back-up power and hydraulic systems, produced water as a potentially useful byproduct, Airbus said.

“Fuel cells offer tremendous potential environmental benefits and operational savings," said Patrick Gavin, executive vice president engineering for Airbus.

Then, just four days later, Virgin Atlantic Airways used its chief energy source — tireless, media-savvy Virgin chairman Sir Richard Branson — to publicize the flight of a Boeing 747 from London Heathrow airport to Amsterdam’s Schiphol airport. The flight, which operated smoothly, used a blend of 80 percent jet fuel and a 20 percent mix of coconut oil and babassu palm oil in one of its four engines.

In an ancillary effort, Virgin is partnering with General Motors to use hydrogen fuel cell technology to power Chevrolet Equinox sport utility vehicles for transporting premium air passengers in Los Angeles to and from the airport. All told, GM is testing 100 hydrogen fuel cell-powered ground vehicles as part of a program it calls Project Driveway.

Algae as a fuel source

Branson, Boeing and other stakeholders in the global aviation system are also touting algae as a possible future jet fuel. Algae, if widely cultivated in ponds, would take up less land than corn, soy or other crops raised for fuel, they say.

Additionally, growing algae wouldn’t produce the carbon dioxide released when farmers clear land to plant crops for other biofuels. Equally important, using algae wouldn’t require diverting staple food crops, such as the corn used to make ethanol, from hungry people to industry.

All this activity is in broad alignment with industry goals such as the International Air Transport Association’s 2007 call for a carbon-free airline industry by 2050 and Scandinavian Airlines’ self-generated plan to cut its carbon emissions 20 percent by 2020 and eliminate them by 2050.

U.S. efforts

No U.S. carrier has yet participated in alternative fuel tests, but that is scheduled to change in 2009, when Continental Airlines plans to test a still-announced type of biofuel on a Boeing 737. The Air Transport Association, the U.S. airline trade organization, argues that Uncle Sam should put serious muscle behind such experiments — and lift the financial burden from airlines.

“ATA supports significant, mandatory general funding for research on alternative fuels, including jet fuel, in the Federal Aviation Administration reauthorization and Agriculture reauthorization efforts," the association says in a statement posted on its Web site.

The FAA is the prime mover behind a project called the Commercial Aviation Alternative Fuels Initiative, designed to develop new aviation fuels.

Washington, through the U.S. military, is already helping to drive development of new fuels. On March 19, the Air Force flew a B-1B Lancer at supersonic speed using a 50/50 blend of synthetic and conventional jet fuel. “The goal is to have every aircraft using synthetic fuel blends by 2011," an Air Force spokesman told reporters after the test.

Commercial civil aviation, which burns more fuel than the military, will need more time. Just how much more remains to be seen.

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