Transport for LondonHydrogen technology
Hydrogen fuel cell buses
Very simply, a fuel cell works like a battery. As hydrogen gas flows into a fuel cell, the hydrogen combines with oxygen and is converted into water. In the process it produces electricity and this powers the electric motor which drives the vehicle.
See a diagram of how fuel cells work (GIF 30KB).
The hydrogen fuel cell buses being introduced in London will use an electric motor, with the hydrogen stored in tanks on the roof.
The only emission from a fuel cell bus is water, which forms a vapour cloud as it leaves the exhaust and enters the atmosphere.
