Fuelling the hydrogen revolution

Most of the large car makers are investing in hydrogen as a clean fuel for the future. But without government support will the hydrogen infrastructure ever be built?

Just a decade ago, the prospect of mass mobile telephone ownership seemed a fantasy. A century ago, the same was true of universal car transport. But where there’s a will there’s a way. Investment and innovation in establishing the necessary infrastructures – roads, service stations, mobile phone masts – paved the way for the realities we enjoy today.

Now one of the most pressing questions facing engineers, businessmen and politicians is the feasibility of renewable, emission-free energy. Road transport contributes 25 per cent of pollutants and greenhouse gases and is the fastest-growing source of carbon dioxide in Europe. Hydrogen-powered transport, by fuel cell or the internal combustion engine, is emerging as the most likely long-term candidate to lead a transport revolution.

Next year, three hydrogen fuel cell-powered buses will arrive on the streets of London, and car makers are clearly beginning to take the environment more seriously. However, for the consumer to perceive this technology as a viable alternative to petrol or diesel, the infrastructure – filling stations and economical production and distribution of hydrogen – has to come first.

At the BMW-sponsored Clean Energy 2002 conference in London last month the car maker’s chairman-designate, Dr Helmut Panke, said that BMW is ‘prepared to invest heavily in hydrogen technologies’. The Hams Hall engine plant in the West Midlands could benefit. However, said Panke, the precondition had to be ‘a strong political commitment to hydrogen’. He added: ‘Further investments can only be justified when infrastructure solutions can be developed and stable political frameworks can be implemented.’

Meanwhile, the government has sent out mixed signals. Last month’s Budget exempted renewable fuels such as hydrogen from taxation and introduced 100 per cent capital allowances for investment in the establishment of a hydrogen infrastructure. Transport minister David Jamieson, however, refused to give explicit backing to hydrogen and expressed doubt that it would be possible to produce hydrogen on a large scale from renewables before 2050.

But head of fuel cell and hydrogen research at Imperial College David Hart says: ‘There’s no reason that we can’t develop the infrastructure with the technology that’s available now.’

There is scope for this country to produce the hydrogen itself. Though the UK is unlikely to match the US$46bn (£32bn) of renewable energy invested in Dubai (of which a significant proportion involves hydrogen production), developing our potentially plentiful wind and wave power resources could make sense. The electricity produced would be used for electrolysis of water, making hydrogen without the greenhouse gases emitted when deriving it from fossil fuels.

Transport problems can be overcome. Liquid natural gas at -120 degrees C is already being pumped from Algeria to Europe, and similar systems could transport liquid hydrogen at -253 degrees C. Distribution models also exist in the UK, with a pipeline in the Tees Valley now in operation for BOC’s new £30m hydrogen plant, which produces the gas for use in polyurethane production. With the appropriate safety standards and cryogenic technology for keeping it cool, hydrogen could be transported in conventional tankers (although BP estimates that the cost of transporting hydrogen will be six times more than compressed gas).

Linking filling stations to hydrogen production – perhaps even providing them with mini power stations for electrolysis – could solve some of the distribution cost problems, and would also benefit communities by creating local energy. In Cambridge a scheme is planned to use solar cells to generate electricity for fuel cell buses.

However, it seems likely that non-renewable products will have to be used to kickstart mass hydrogen production.

Work is also under way on making filling vehicles with hydrogen as easy as it is with petrol. A prototype hydrogen fuel cell filling station was built in West Sacramento during 2000 under the California Fuel Cell Partnership initiative, which involves several major car manufacturers and oil companies. BP’s hydrogen technology manager, Dr Michael Jones, concedes that having cost £1m ‘it looks like an industrial plant and is the size of a tennis court while only storing about 20 per cent of the amount of hydrogen a typical urban retail site would dispense in conventional fuels daily.’

Munich Airport’s automated demonstrator station, developed with BMW, illustrates better how filling up could change in the future. A two-piped coaxial coupling ‘docks’ with the car, flushing itself out with helium to expel unwanted air. The pressure in the service station tank is then used to feed liquid hydrogen into the car’s tank, with excess gas routed back to the station.

Estimates vary as to how many more stations could be set up in the near future, and this is the crux for the consumer. Perhaps 20 could be built in the next five years, rising to 1,000 in the next 10; some sources think 2,000 could be ready by 2007.

But it will be expensive. Jones thinks that at an optimistic target of £400,000 to establish one hydrogen dispenser at a 300-car service station, the cost of converting just BP’s 1,300 UK stations would be £520m. Fleet vehicles, particularly buses, would be most suitable for liquid hydrogen initially with refuelling points at depots and stations. BMW has discussed supporting the establishment of refuelling points near its own service and sales outlets.

Hydrogen technologies dovetail neatly with the UK’s industrial base. Director of the Centre for Automotive Industry Research at Cardiff University Prof Garel Rhys estimates that by 2004 the UK automotive industry could be producing 4.25 million vehicles and engines, employing 50,000 and turning over £1bn; it will therefore be in a strong position should hydrogen internal combustion engines, favoured by BMW, catch on. Petrochemical companies also have a vested interest.

BP vice president David Baldry says that in the next three years 50 per cent of his company’s sales could be of ‘clean’ products. The firm is providing the refuelling point for the capital’s ‘clean’ buses.

Nonetheless, definite plans for installing the infrastructure are still a long way off. When cars and mobile phones were in their infancy the support network for them could be allowed to grow organically without government intervention. But society is irreversibly wedded to motor transport, and needs to begin the conversion to ‘clean’ fuels sooner rather than later before more environmental damage is incurred.

It is in the interests of car manufacturers and fuel suppliers to get together to establish an infrastructure, if nothing else to keep themselves in business in a changing world. But government should take a clearer lead to accelerate the process. The necessary technology is almost here. Businesses like BMW and BP say they have the vision to put it in place, but the politicians still need persuading.

Sidebar: BMW takes the dual fuel approach

While DaimlerChrysler, GM and Ford invest in fuel cells, BMW’s strategy is promotion of a dual-fuel liquid hydrogen/petrol car.

A ‘clean’ 7 Series car, the 745h, is to be produced in limited numbers within 10 years. The basis of this strategy is the immediacy of the technology: drivers can use a ‘bivalent’ car now, despite the lack of a hydrogen infrastructure.

For a strongly branded company like BMW, an additional reason is the car’s acceptability to the core customer. ‘The performance and characteristics of the internal combustion engine reflect our brand values,’ says BMW chief executive Helmut Panke: ‘If it had an electric motor it would be less fun to drive.’

Though the car’s power in hydrogen mode is only around 60 per cent of its power in petrol mode, Panke says, ‘You will not feel the difference between a gasoline and a hydrogen car.’ BMW plans to demonstrate this to the media later this year, and claims that, when optimised, hydrogen engines will produce as much power as their petrol equivalents.

Though at first hydrogen engines will cost serious amounts, their main rival, fuel cells, are still a long way from being affordable too. Without moving parts, fuel cells have the potential to become cheaper in the long run if mass production starts, but contain a high level of precious metal (in catalysts) and cost 10-20 times as much as hydrogen engines.

After a century of development combustion engine technology is at its peak. Clearly the thought process at BMW has been ‘why not take our mature product, and change it to use a different fuel’.

BMW’s 12-cylinder 750hL prototypes, of which 18 were built, clocked up over 150,000km of motoring between them and persuaded BMW to proceed with the strategy. Next year production of the V8 745h will commence, and in the future a 12-cylinder 760h could be on the cards.

A number of problems had to be solved to enable BMW to do this. First and foremost was the car’s own fuel tank. The prototype tank came from Linde, but production is now in the hands of BMW’s Austrian neighbours, Magna Steyr.

Magna Steyr has experience in cryogenic hydrogen storage from the Ariane 5 space programme, and designed a tank to hold 9.5kg of liquid hydrogen (comparable to 50 litres of petrol) at -253 degrees C. The trick is in the insulation. Layers of glass fibre and plastic matting are sandwiched between stainless steel inner and outer walls, providing insulation equivalent to that provided by 30m of polystyrene.

Initially, when the engine is started, gas is taken from the tank and when pressure falls to a suitable level a valve switches to a liquid supply. The remaining pressure helps feed the fuel to the engine while heat exchangers along the fuel lines turn the liquid hydrogen back into gas for combustion.

However, at 170 litres, the amount of boot space the tank itself takes up could be a stumbling block to the consumer. Magna Steyr is researching ‘freeform’ tanks to replace the existing cylindrical shape, and is also looking at hydrogen ‘slush’ which would enable 20 per cent more to be stored in the same volume.

Premature ignition can cause backfiring in hydrogen engines, so BMW developed a new ignition module. The ignition system also required conversion to a static voltage distribution system, and (ironically) a small fuel cell acts as the auxiliary power unit for the vehicle’s electric system.