One of the giants of the aircraft industry is considering the possibility of installing a hydrogen-powered fuel cell which would provide backup power in aircrafts in emergency situations when the main power goes offline.

Boeing started a collaboration with Sandia National Laboratories to examine the feasibility of using the alternative fuel source on commercial and military aircraft, which currently use a variety of techniques for providing backup electrical power to critical subsystems during emergency scenarios.

The most commonly used are dedicated battery power, in-flight operation of the auxiliary power unit, a ram air turbine, but these are not all the existent applications. It seems that with the recent boost in alternative fuel applications, more and more companies are becoming interested in fuel cells and what these can do.

Fuel cells differ from batteries in that they consume reactants, which must be replenished, while batteries store electrical energy chemically in a closed system. Additionally, while the electrodes within a battery react and change as a battery is charged or discharged, a fuel cell's electrodes are catalytic and relatively stable.

The joint project is focused on the use of a polymer electrolyte membrane (PEM) fuel cell for backup power. Sandia is leading investigations looking at electrical and environmental requirements, storage issues, and efficiency.

"Fuel cell technology represents a straightforward and innovative approach to gaining experience with alternative energy sources for airplane electrical power," says Joe Breit, project manager and an associate technical fellow at the Boeing Systems Concept Center. "A significant part of our focus at Boeing Commercial Airplanes is looking at environmentally progressive technologies that can further reduce dependencies on oil-driven power sources. Our collaborative work with Sandia on this application is a step forward in that regard."

The main advantage of the fuel cell is the fact that they can operate virtually continuously as long as the necessary flows of fuel (on the anode side) and oxidant (on the cathode side) are maintained. Because fuel cells have no moving parts, and do not involve combustion, in ideal conditions they can achieve up to 99.9999% reliability.