There has been a great deal of discussion as to the use of hydrogen as a fuel, there are a number of manufacturers who are working on ways to make it a practicle solution.   It is clear why!  Hydrogen is as much as can be possible, an infinately renewable resource, being the most common substance in the universe.  And it burns cleanly, the main product of its combustion is water. although burning any substance produces oxides of nitrogen which creates their own environmental worries.

So if Hydrogen is easily available and its output is water, why are we not all running on it by now?  Well, there are many problems that are being ironed out at the moment.  Not the least of which is the fact that at normal temperatures hydrogen is a gas - Petrol and Diesel are liquids, so when stored in a tank they wait there until used - a gas will try and escape at every oppertuniy.

The only way to keep Hydrogen a liquid would be either to keep it at a very low temperature at all times - not very practicle - or to keep it in a highly prssurised tank - could be very dangerous if damaged, the third option is to store the hydrogen in a honeycomb structure - this too has its downfalls, it will be expensive and won't be able to hold as much fuel.

So Is it Safe?

There are safety issues, too. some say it has far more safety issues than petrol.  A different view would say that hydrogen is no more dangerous that any other feul - they all need to be hadles safely!

One of the biggest problems about putting hydrogen into a tank is the fact that any static electrical charge could lead to an explosion. which is why on each of the two FCX vehicles which were built by Honda and have been leased to the city of Los Angeles there have been two fuel doors. Opening the first of them reveals a connection for a grounding wire which has to be put in place before the second is opened to receive the high-pressure nozzle with leakproof seal which allows the hydrogen to be put into the tank.

In addition, hydrogen is odourless (the universe would be a very smelly place if it weren't) and burns with a clear flame. Both these aspects make it difficult to spot that there is a risk of explosion before the explosion actually takes place. Hydrogen can also penetrate some metals and make them brittle.

The explosive qualities of hydrogen are also being discussed by safety experts. There's no point in complaining about the fact that it does explode, because that is what any fuel intended for use in an internal combustion engine must do. What is being said about hydrogen in particular, however, is that it is more explosive than petrol.

However, any fuel has to be present in a certain density before it will burn, and this density is lower in the case of hydrogen than in that of petrol. Less of it therefore has to be ignited before a reaction will take place - or, to put it another way, hydrogen is more likely to go bang than petrol is, though petrol will produce the bigger bang.

Green Qualities And Transport

The question also arises as to how environmentally friendly hydrogen-fuelled vehicles actually are. If you measure what comes out of the exhaust, there is no argument: hydrogen beats petrol hands down. But how do you create the hydrogen? The best method is to pass an electric current through water. To do that you need to create the electricity, and if this means increasing the workload on coal- or nuclear-powered generating stations, the environmental advantage of using hydrogen becomes less obvious. Electricity generation by wind, wave power or the force of water falling down a hillside (as in the case of hydro-electric stations) is not sufficiently widespread to restore the balance.

Having created the stuff by whatever means, you then have to transport hydrogen to outlets where customers will be able to buy it. Another point not often raised in discussions like this is that you need an awful lot of hydrogen to power a car (another result of the fact that it does not create large explosions), and that means carrying it around the country in very large quantities. A motor industry source recently voiced this concern to CARkeys as follows: "If all the cars in the world were converted to hydrogen tomorrow, one in every five vehicles on the road would be a hydrogen-carrying tanker."

That's a lot of tankers, creating a lot of traffic. And every one of those tankers would have exactly the same storage safety issues mentioned above.

Experts say that mass-produced hydrogen-powered vehicles are at least a decade away. At a time when environmental issues are at the forefront of so many people's minds, hydrogen seems to be in one sense the perfect fuel, but those ten or more years are going to have to be spent addressing a great many issues before its everyday use becomes a practical proposition.

Information taken from Carkeys