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The Guardian: Supply lines

Published: Jul 20, 2006

London is not alone. Hydrogen-powered bus projects are being prepared all over the world. From Cambridge to California, Norway to Nagoya, Perth to Porto, pilot schemes are being readied and supply lines put down. Last week, Shell announced a partnership with the Dutch bus manufacturer Man that will see 20 hydro-buses on the streets of Rotterdam by 2009.

The appeal of hydrogen is easy to understand. It is the most abundant element, and abundantly available on Earth (though locked up in water), and its oxidation produces huge amounts of energy per unit mass. The hydro-buses – which experts say are as safe as conventional ones – use a process invented in 1839 by William Grove, a British barrister and amateur physicist, in which hydrogen is combined with oxygen within a fuel cell to generate a powerful electric current. The hydro-buses are quiet because the fuel cell, which is held in the roof, removes the need for an engine. The only exhaust is steam, because the hydrogen removes the need for the diesel engine.

But it’s not quite so simple as filling a bus with hydrogen and driving away. The hydrogen molecules must first be extracted from another source, usually either water or a fossil fuel such as coal or gas. The cleanest way to make hydrogen is to electrolyse water using electricity generated from renewable sources; solar power has been used to power fuel-cell buses in Perth in Western Australia. But in London’s case, “this means obtaining hydrogen from natural gas”, says Mark Watts, the London mayor’s adviser on energy, transport and air quality. The trouble is, he explains, that this process still produces carbon dioxide, “although it is about 30% less than the amount from the equivalent diesel engine”. This also means the carbon dioxide can be released into the atmosphere miles from London.

The use of hydrogen is being held down by price. It costs up to 10 times more to take a bus passenger one mile using hydrogen rather than diesel.

Paul Medlicott, of the London Hydrogen Partnership, an organisation devel oped by the mayor’s office “to drive London towards a hydrogen economy” says London can help drive down the cost of hydrogen and the cost of the fuel cells. Medlicott hopes that by ordering more buses and sharing the cost with “partner cities”, London can kick-start its own hydrogen economy. He also stresses that hydrogen is at least as safe as petrol. and its also non-profit sister websites,,,,, and are all owned by John Donovan. There is also a Wikipedia article.

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