The dream of using hydrogen as an everyday fuel in road vehicles still faces many obstacles before it becomes a reality, not least of them safety at the most vulnerable point - the filling station. Brian Byrne reports.
Motorists used to simply sticking a nozzle into an opening and squeezing the trigger will find filling up a more complex operation, because of the different characteristics of hydrogen compared to current fuels.
The much higher pressures required to keep hydrogen liquid - some 10,000 psi compared with the 3,000 psi of LPG on-board storage tanks - will mean more care has to be taken with hoses and car-connection valve systems, and might even require specialist operators under health and safety regulations. Self-service would be a thing of the past.
Other risks include the ease with which a static electricity spark could ignite leaking hydrogen at a concentration as low as four per cent in the atmosphere. Vehicles being refuelled will likely have to be 'grounded' in some way..
The kind of infrastructure merely to safely transfer the fuel will require almost space programme levels of investment not just in physical terms, but also to establish technical standards and meet cost/performance targets.
So, while Iceland opened its first hydrogen 'filling station' earlier this year under an EU programme that will see several other such installations opened on pilot bases throughout the community, it's a specialist operation to fuel buses in the country's capital, Reykjavic.
For a longer time-frame than many lay commentators would like us to believe, mass transit systems are more likely to be commonly hydrogen powered than personal cars, for safety, cost, and efficiency reasons.
On-board storage is the key inhibitor, as current experimental personal vehicles have a range of only about 100 miles at best because of size and weight of tanks considerations.
In the latest hydrogen power industry report from the US - the Hydrogen, Fuel Cells & Infrastructure Technologies Program - investigators say current target achievement possibilities see only very low volumes of 'demonstration' vehicles being available by 2005, while five years beyond that hydrogen will still only be available on a 'limited number of least demanding platforms'.
It will be 2015, the reports says, before hydrogen power will be suitable for mass production in a 'full spectrum of vehicles'.
Even by 2005, by today's prices, the pumped cost of hydrogen is expected to be still twice the cost of gasoline, and it will be 2010 before the par cost target might be achieved.
In an industry so heavily engineering-based, such targets are notorious for arriving late against forecasts.
Ironically, public perception of the safety of hydrogen is likely to be one of the biggest influencers on the move towards more common use, once the technologies for production, storage and delivery are in place.
Regularly regurgitated images of the pre-WW II Hindenburg airship disaster, which used lighter-than-air hydrogen for 'lift', rate high in the folklore of hydrogen catastrophe, as do those of the space shuttle Challenger disaster. Hydrogen is one of the components of rocket fuel.
However recent studies of the Hindenberg accident have convinced researchers that it was not the hydrogen burning that resulted in the deaths of more than 30 passengers and crew, but the paint and fabric of the dirigible which ignited in a lightning strike.
Hydrogen, being lighter than air, dissipates very quickly if released.
And even if it ignites, its fire burns out quickly and with very little heat radiation.
In fact, according to DaimlerChrysler engineer Richard Tuso, a fire from a hydrogen tank in the rear of automobile will leave the back windows of the car unscathed, while a similar gasoline fire would melt the windows.
That's why the fleet of experimental BMW 7-series hydrogen-powered cars now touring the world have systems that automatically open all the windows in the event of a detected leak, to quickly dissipate the hydrogen into the atmosphere.
US scientist Michael Heben of the National Renewable Energy Laboratory says the distribution of 'unsubstantiated and incorrect lore' on the Hindenberg incident has greatly harmed efforts to develop hydrogen technologies for the replacement of fossil fuel.
On the other hand, David Morris, vice-president of the US-based Institute for Local Self-Reliance, has dismissed the concept of a hydrogen economy as only another way of avoiding more development of renewable energy.
"It has taken 30 years for the renewable energy industry to capture one per cent of the transportation fuel market using ethanol, and for two per cent of the electricity market using wind, solar or biomass," he says.
"It would be much better to spend the hundreds of billions of dollars mooted for hydrogen development on getting that percentage to 25 per cent or even 50 per cent in the same time frame."
He also says that carmakers should be concentrating on improving battery power storage to improve the potential of hybrid cars currently being produced primarily by Toyota and Honda.