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Hydrogen buses

 Fuel cell buses Water! That is all a hydrogen fuel cell bus releases into the air. Clean, green and coming to a bus stop near you, they are the ultimate in environmentally friendly buses.

Having taken part in a really successful European trial we now want to have ten hydrogen buses running in London by 2010. Five will be hydrogen fuel cell buses and five will be hydrogen internal combustion engine buses.

Once again we'll be leading the way in hydrogen transport technology.

How fuel cell hydrogen buses work

Hydrogen fuel cell buses 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.

Diagram of fuel cell

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 bus. See a diagram of how fuel cells work (GIF 30KB)

Both types of buses will also use hybrid technology to make them as efficient as possible and help them go further before having to refuel.

How hydrogen internal combustion engine buses work

The five hydrogen internal combustion engine vehicles (H2ICE) will use a specialist ICE V10 engine which is powered directly by hydrogen stored in tanks on the roof of the bus.

As there's no carbon in the fuel, hardly any emissions are produced

Using this technology, the hydrogen burns in engines pretty much the same as in traditional petrol/diesel vehicles. But as there is no carbon in the fuel, hardly any emissions are produced. Emissions testing will be done as part of the test and evaluation program.

How hydrogen is made

Hydrogen can be made from a number of different sources, including natural gas and by splitting water into hydrogen and oxygen (electrolysis). Air Products will supply the hydrogen to the 10 buses.

Who will be supplying and driving the hydrogen buses

American company ISE will supply the ten hydrogen buses to London, working with Ballard and Wrightbus. We awarded the contract to operate them to First Group, who will run them on a single route.

Hydrogen Bus Alliance

We helped to establish the Hydrogen Bus Alliance, an international partnership. Members are committed to supporting the rapid development and commercialisation of hydrogen technology in public transport.

Who took part

London Buses

London Buses, part of Transport for London, is responsible for achieving environmental targets and standards for the whole of London's bus fleet, as required by the Mayor's Air Quality Strategy.

First Group

The First Group operates around one sixth of the London bus network. The company's experience, support and expertise in transit management is crucial to ensure the project is conducted and assessed to rigorous standards.


ISE will develop and integrate the hydrogen technology into the buses and provided technical support during the trial.

Wright Group

Wrightbus will design and manufacture the bodywork for the hydrogen buses.


Ballard with supply the fuel cells to be used on five of the buses.

Air Products

Air products will supply the hydrogen for the buses and the refuelling equipment. They will also provide specialist technical support during the project.

Department for Business, Enterprise and Regulatory Reform

The Department for Business, Enterprise and Regulatory Reform will support the project through a grant from its Hydrogen Fuel Cell programme.

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