The goals of the Advisory Council for Aeronautics Research in Europe (ACARE) to reduce CO2 emissions by 50 percent, NOx emissions by 80 percent and noise cut by 50 percent by 2020 has seen aircraft manufacturers and airlines looking at alternative fuels such as biofuel. While not feasible for powering the flight of the aircraft itself, Airbus has also been looking at the potential for fuel cell technology to power a number of aircraft functions, such as autonomous taxiing.
In 2008, Airbus, together with its research partner the German Aerospace Center (DLR), performed the first successful flight test of fuel cell technology where a fuel cell system provided power for the aircraft's back-up systems. Airbus and DLR are now looking at the potential of fuel cell technology for powering other aircraft functions including autonomous taxiing.
A DLR designed technology demonstrator has been installed in a DLR owned A320 ATRA (Advanced Technology Research Aircraft) consisting of a fuel cell system powering two electric motors built into the rims of the aircraft nose wheel. The 47-ton aircraft taxied around Hamburg Finkenwerder Airport propelled by an electric nose wheel on July 1st, 2011.
DLR says that an airliner fitted with a fuel cell-powered nose wheel would be able to move from its stand to the end of the runway without using its engines, thus allowing emissions produced in airports to be cut by up to roughly 18 percent and the noise during taxiing to be almost eliminated completely.
Although DLR is still working on detailed models of the potential savings at airports, Thorsten Mulhouse from the DLR Institute of Flight Guidance (Institut für Flugführung) says, "the potential saving at Frankfurt Airport from the use of electrically-driven nose wheels for Airbus A320 class aircraft is about 44 tons of kerosene per day."
Additionally, the use of fuel cells would cut the amount of time the aircraft's main engines are operating, which would allow the engine maintenance interval to be extended. DLR estimates that on short-haul services, with up to seven take offs per day, using an electric drive for ground maneuvering would allow for a reduction in engine operating time of up to two hours per day.
In addition to autonomous taxiing and backup systems, Airbus and DLR are also working on replacing the Auxiliary Power Unit (APU) with a fuel cell system. The APU supplies the on-board electrical and compressed air systems, including the air conditioning, when the engines aren't running.