Hydrogen propulsion: five questions and answers

1. How does hydrogen propulsion work using the fuel cell principle?

Fuel cell vehicles (FCVs) are driven by an electric motor, just like electric cars. However, according to the definition supplied by the German motoring organisation ADAC, the electricity required for this is not supplied by an on-board battery but is actually generated within the fuel cell in the vehicle. This comes about through reverse electrolysis. The fuel cell converts hydrogen and oxygen (drawn from the atmosphere) into water and, in the process, produces electricity and heat. Fuel cell propulsion in vehicles is efficient and quiet. The high torque of the electric motor permits gear-free acceleration.

A vehicle fuel cell is made up of a large number of individual cells which, when they are connected in series to form a 'stack', generate sufficient power to drive an electric motor. This process causes no emissions; only heat and water vapour are released. This means that a fuel cell car is a Zero Emission Vehicle (ZEV). The fuel cell also replaces the alternator in a car; it provides the electricity for the ever-increasing electronic controls now found in cars and the heating and air-conditioning systems.