With demand for air transport doubling every 15 years, the global airline industry will require nearly 30,000 new aircraft (over 100 seats) by 2032. Simultaneously, the dual factors of high jet fuel costs and industry commitments to halve 2005 CO₂ emissions levels by 2050 are driving the search for alternative solutions to fossil-fuel based propulsion and energy sources, Airbus said.

With this in mind, Airbus has identified hydrogen fuel cells as a future, emissions-free substitute to the small gas turbine engine Auxiliary Power Units (APUs) used for generating on-board electrical power and heat while the aircraft is on the ground.

Almost every airliner designed and built since the advent of jet travel in the 1950s has been equipped with an APU, which is located in the tapered tail cone section of the rear fuselage. Replacing the fossil-fuel powered APUs with hydrogen fuel cells would help achieve the goals of emission-free and low-noise aircraft operation.

Besides emission-free and low-noise aircraft operation, fuel cells would reduce the overall weight of aircraft, leading to lower fuel burn and operating costs together with further reduced carbon emissions during flight. As by-products, hydrogen fuel cells could enable aircraft to generate their own water supplies. They would also have a safety benefit through their ability to generate inerting gas used to reduce flammability levels in aircraft fuel tanks and for suppressing any cargo hold fires.

Fuel cells, because they do not have any moving parts, are less maintenance-intensive than conventional APUs. They could also potentially replace heavy batteries and conventional fuel tank inerting systems. In doing so they would reduce the weight and fuel consumption of fuel cell-equipped aircraft.

Although Airbus has already performed test flights involving fuel cells to power individual emergency power systems, the knowledge and technology maturation is still on its way to reach a level to permit the complete replacement of the electrical power systems with a multi-functional fuel cell.

The project with HySA Systems Competence Centre will go some way to closing that gap, Airbus suggested. It is being undertaken at postgraduate level and will identify the factors influencing fuel cell performance, aging and monitoring and will then consider how these could be adopted for use in aircraft.