The use of alternative, environmentally compatible power sources for aircraft is moving ahead cautiously. Although full details have not been released, Airbus has confirmed that it had successfully flight-tested a fuel-cell system in an A320 to power backup hydraulic and electric power systems. Airbus claimed it as a “first” for a civil aircraft, and it followed closely with another first for a commercial aircraft when it also flight-tested an A380 equipped with one engine that burned a gas-to-liquids (GTL) fuel.
The fuel-cell system is the result of work with Michelin and the German aerospace research center, DLR. Airbus has an ongoing research philosophy in place to evaluate the potential use and environmental benefits of fuel-cell technology and zero emissions power generation in civil aviation, and had announced that it intends to play a significant role in the creation of an eco-efficient aerospace industry.
“During the test, the fuel-cell system generated 20 kW of electric power,” announced Airbus after the trial flight. “The fuel-cell system powered the aircraft’s electric motor pump and the backup hydraulic circuit and also operated the aircraft’s ailerons. The system’s robustness was confirmed at high-g loads during turns and zero-gravity maneuvers. During the test, the fuel cells produced around 10 L of pure water.”
The flight trial is one of the first steps of Airbus’ low-emissions program. The results will enable the company and its partners—including Michelin—to further develop ways to implement fuel-cell technology for replacing other aircraft systems such as the emergency power systems and auxiliary power units. Airbus believes the program will significantly reduce the noise and emissions levels in and around airports.
Earlier this year, an Airbus A380 flight-tested one of its four Rolls-Royce Trent 900 engines with Shell GTL jet fuel. The flight was from Filton, U.K., to Airbus’ headquarters at Toulouse, France. The A380 has segregated fuel tanks, facilitating the flight test, during which engine one burned a blend of GTL and jet fuel. The aircraft’s remaining three engines used standard jet fuel.
Airbus, Shell, and Rolls-Royce believe GTL could be available at certain locations to make it a practical and viable drop-in alternative fuel for commercial aviation in the short term. GTL is almost free of sulfur.
Another significant development in the aerospace industry’s move toward alternative power sources came with the news shortly after the Airbus flight of what was claimed as the world’s first commercial airline flight powered by renewable energy. With a tank carrying a biofuel blend to supply one of its four engines, a Virgin Atlantic Boeing 747 flew from London to Amsterdam. The biofuel contained babassu oil and coconut oil. The airline’s founder, Richard Branson, said of the flight: “Today marks a vital breakthrough for the whole airline industry.” The project involved Virgin Atlantic, Boeing, and GE-Aviation.
But Branson does not see babassu and coconut oil supplying the airline’s fuel needs on a regular basis. And he said the airline did not wish to use biofuels such as corn oil because their growth competed with staple food sources. He believes sources such as algae produced in, among other places, sewage treatment farms, would provide a more likely and acceptable source of renewable fuel for the airline industry. There is a strengthening belief that second-generation biofuels produced from municipal waste and waste wood products have more environmental credibility than first-generation types.