Fuel Cells Flying High

Fuel cells--electrochemical devices that generate power without combustion, and with little or no emissions, depending on the fuel source--are being considered for aviation because they can operate using a variety of fuels, including hydrogen, renewable fuels, and traditional hydrocarbon fuels such as natural gas, propane, kerosene, and JP8. Fuel cells attain high efficiencies, typically 50-60%, and efficiency benefits can reach 90% or more when a fuel cell's waste heat is recovered and used for heating, cooling, and provision of hot water. This article provides a review of ongoing work by several different research entities and private companies into fuel cell applications in aircraft. Fuel cell systems can potentially provide power; emissions-free ground operation, including autonomous taxiing, maintenance bus supply, and cargo reloading; electrical main engine start; electrical environmental control system supply (air conditioning); water generation; heat generation for icing prevention and hot water; explosion suppression via inerting of the tanks; and cockpit and cabin air humidification. Using a fuel cell in multiple applications may reduce a plane's payload, lower maintenance costs, and reduce emissions, potentially justifying the present higher cost of fuel cells compared to current technologies.