“ although you could argue that the accidents are rare and potentially worth the risk?”
I agree. I don’t know if they’re technologically feasible at the price point necessary to put them in a few billion cars. But this “safety” obsession has gotten old.
You might have poor friends who have cash flow problems. When I was a kid my parents wouldn’t fill up the tank, they’d put L20 000 in it ($15). About half way up. They couldn’t afford more.
For people like this, how much the car costs per stop is important. Especially if a re-fueling typically occurs after the next pay period.
No, it isn’t. Gasoline is dangerous, but it’s a liquid. H2 is a gas, under extreme pressure, and with a very low spark energy.
The spark (ignition) energy is very important safety wise. Nothing will light without an ignition source. In fact hydrogen is more dangerous wrt to gasoline than gasoline is wrt to flour (yes, flour can explode). That is:
“Hydrogen bomb” is a little exaggerated. But to your detractors:
“More than a gasoline bomb, hopefully. Gasoline is more dangerous.”
Citation needed. How is gasoline more dangerous? While gasoline is very dangerous, gasoline is a liquid and will not burn until vaporized; Gasoline is dangerous because it vaporizes quickly. H2 is already a gas and has a ridiculously low spark energy. Furthermore H2 is under pressure.
Gas does have a lower auto-ignition T than H2, that’s no fun, but overall H2 scores worse than gasoline.
“Do you ride on a CNG city bus?”
CNG stands for Compressed Natural Gas; i.e. methane. Methane is a lot easier and safer to use than H2 because it:
- Packs a lot more energy vs. P so the tanks don’t have to be as strong
- Doesn’t embrittle the container
- Much higher spark energy (in fact, CH4 is kinda hard to light)
- Smaller flammability range (i.e. mixture with air that will ignite)
- lower auto-ignition T
Perhaps a freeze thaw cycle that split one to many bolts?