Jim Logajan wrote in
:

Bertie the Bunyip wrote:
The volume thing is a non-issue with metal hydride tanks as well as
the safety issue.

The information I've found on metal hydrides is not nearly so
optimistic. Allegedly about 4 times heavier per unit of energy than
gasoline and many of the known metal hydrides (e.g. lithium)
themselves being health hazards.


Well, they're tanked for life and like for like the crap that's in
modern gasoline is probably worse. Metal hydrides are heavy, no doubt
about it. Very heavy. Too heavy for airplanes, certainly. There's a
number of hydride combinations that look to improve on that. They do
provide a practical way of carrying H2 safely in a reasonable volume,
though. I'd be a lot more comfortable driving a car so equipped than an
H2 powered car with a simple pressure tank. They have another drawback
as well. Temperature. The hydrides only release the H2 at a usable rate
when the temperature in the tank is high enough. How high depends on the
hydrides used, but it's warmer than ambient most of the year. So you
need to heat it up a bit. Not a big problem, but it is an added
complication.


Bertie