Looking exactly like the familiar London black cabs, a fleet of taxis that run on hydrogen/fuel cell technology are proposed to be ready in time for the Olympic games, to be hosted in London in 2012. The top speed of these vehicles is 81 mph and they can be driven for 250 miles on a single filling of hydrogen. Hydrogen is of course not a fuel, but an energy carrier, and must be produced, ideally using renewable energy. Therein lies the snag. Iceland is already building a hydrogen grid, but is in an extremely fortunate position since it has ample supplies of geothermal energy. There are also only 300,000 Icelanders, and so the overall demand on the technology is accordingly less than in a country with 60 million, as is the population of the U.K.
In Britain, the renewable electricity would be provided, ideally at any rate, from wind-farms and solar energy plants, but until that is achieved on the grand scale, the hydrogen will be produced from natural gas rather than splitting water by "green" electrolysis. In a chicken and egg situation, the driver of a single hydrogen car would have a poor choice of filling stations to choose from, but as demand increased, more of them would appear, so goes the market-driven argument. Thus a fleet of London taxis would need some concomitant infrastructure in-place from the start.
Kit Malthouse, who is the deputy London mayor, made an announcement in 2009 that by 2012 there would be six hydrogen filling stations in the city, and that somewhere between 20 and 50 taxis should be on the roads by then, as part of the "Black Cabs Go Green" programme, along with an even more ambitious 150 hydrogen-powered buses.
The idea is to modify a standard black cab, and the initial few such taxis have been made at the Lotus headquarters in Norfolk, funded by the government's Technology Strategy Board. The consortium for the project is headed by Intelligent Energy, who make the fuel cells, while Lotus incorporates the cell into the body of the car, using a design in which a tank containing hydrogen under pressure occupies the space of a normal internal combustion engine. Electricity from the fuel cell is fed to a battery pack under the floor of the taxi, which is used to provide propulsion for the wheels.
So in effect this is an electric car. However, there are apparently considerable space-savings over a normal electric car, in which most of the volume of the rear is occupied by the battery-pack, i.e. where the passengers normally sit, and since the energy-source (I am avoiding the term "fuel") is carried on-board there is no need to charge the batteries during the day.
I have grave reservations about the practicalities of hydrogen cars, although in principle they might seem ideal. If the hydrogen can be made from water using green electricity, then we have a pollution-free transport system. However, the infrastructure required from scratch to produce the hydrogen in the first place would be huge, let alone issues of its distribution. I think that as far as 2012 is concerned, there may be a few flagship taxis on the streets of London, but we are so far from anywhere near the 33 million vehicles that are on the roads of Great Britain, and powered by oil, that the scheme is merely a political curiosity. Still, some will say that at least it is a start.
So it is, but if we are at the point of peak oil, and it is impossible to replace oil-powered vehicles by hydrogen/fuel cell alternatives before we experience severe shortages of oil-derived fuels, their impact will be nil. It is more important to face-up to the pressing and undeniable dearth of liquid petroleum fuels and to redesign as best we can, our society to one that is less dependent on transportation at the level we have come to take for granted.
"Hydrogen taxi cabs to serve London by 2012 Olympics," By Alok Jha: http://www.guardian.co.uk/environment/2010/feb/22/hydrogen-taxi-cabs-london-2012-olympics