Originally posted 13 Oct 2006:
A follow up on Stan Ovshinsky's method of storing hydrogen in solid metal -- it is metal in a powder form, and it is completely inert; which is obviously a good thing! The challenge is, that when the hydrogen is "charging" the metal, it generated a lot of heat, and currently they use a water jacket to cool it.
Here's what I suggested to them in an email: why not charge up some of the (nickel metal hydride?) metal powder in a machine where you can recover the heat and use it -- and then use a pneumatic vacuum system to evacuate the spent powder out of the car's tank, and then use the same system to fill it again with charged powder?
This would also avoid the greatest hazard of having to have the "user" working with the hydrogen gas, and you could gain efficiency by recovering the heat.
A little background: Stan Ovshinsky has retrofitted a Toyota Prius with a hydrogen tank, that because it uses the (NiMH?) metal powder to hold the hydrogen, like a sponge holds water -- the tank holds twice as much hydrogen as it could in the same volume under high pressure! The engine is converted to burn the hydrogen, and the exhaust is water!
The other piece of this idea is to produce the hydrogen right in the fueling station. Using electricity from the grid, at least; or better yet use PV, and/or wind generators, and/or a hydro-generator, and/or geothermal, etc. to generate electricity on the spot (to avoid all transmission losses!) and store the hydrogen in the solid metal; where it is safe and stable.
Sounds like a good business plan for a franchise, huh?