Why is it so difficlt to store hydrogen?

[Laura Loo]

I'm watching top gear the other night and jeremy clarkson shows me the first ever car to run on hydrogen.

Great!I'm all up for saving the planet and all that.

He goes on to say that the first person to work out how to store hydrogen safely will become very very rich as this could be the way forward for fuelling our vehicles.

See I do ask sensible questions!

[Eurox]

Because hydrogen is so flammable. A single spark, or excess heat from the engine, could cause the pressurised Hydrogen to explode and turn the car into a fireball.

[buildersmate]

But this is also true of LPG (and petrol vapour).
Is it not more to do with the huge pressure under which hydrogen would have to be kept, in order to get a reasonable calorific value from it, per cubic metre stored?

[jake-the-peg]

Well it's to do with the amount that you're storing, the time to refuel and safety.

BMW are favoring this technology and the best that they've managed so far is a range of 217 miles http://archives.cnn.com/2001/TECH/science/03/1 6/hydrogen.cars/

However in order to get that they couldn't compress enough hydrogen into gas cylinders. They'd have to be ridiculously strong and hence heavy . So they use liquid hydrogen but that needs to be at -250 degrees C which makes keeping it cold and refueling it a nightmare.

Remember Nitrogen and Oxygen are liquid at warmer temperatures so if you expose it to the air you'll start liquifying the air!

Then there's the danger aspect, not only is it explosive in air (and way more so than petrol) but there's the usual danger of cold burns with liquid gasses - just imagine a rear-end shunt!

There is another technology which is solidifying the hydrogen into a solid metal hydride which gets around a lot of the problems but is still too heavy last one of these I saw weighed half a tonne.

However I think BMW has it right Hydrogen is much better than batteries as a way forward-

Who wants to change batteries or recharge every 250 miles?


Here's a kit to run your car on it now
http://www.switch2hydrogen.com/
Just not approved yet

funny that :c)

[Loosehead]

Further to the above is the problem of how to create a safe network of outlets for refuelling the masses. I mean imagine all the garages were now storing large amounts of hydrogen, very dangerous, as already pointed out Hydrogen is far more volatile than petrol/LPG. The storage tanks etc would have to very special.

[Seafarer1966]

Remember the R101 airship burning. They filled Zeppelins with hydrogen to float. Highly flammable. These days airships use Helium.

Interesting the point made on LPG. I do know of a farmer who clipped his static LPG tank with a vehicle and punctured the metal tank skin. It uprooted off its bolts, rocketed into the air and was found in a field 500 yards away. Thats some pressure!