Comment by fuzzfactor
9 hours ago
Good question.
It's just the physical properties of methane.
That's why they use high-pressure tanks because with low-pressure gas storage, the tank needs to be bigger than the car.
Energy density of methane is still lower than any other hydrocarbons.
Again: current day CNG ICEs don't actually have "fuel tanks bigger than the car".
That's because they use high-pressure tanks.
Actually higher working presure than regular welders' oxygen tanks.
Too bad the higher the pressure, the heavier the tank, especially steel.
I had a pretty good job offer from a company that was going to start building CNG tanks out of carbon fiber.
This was a few years before the failure of the Titan submersible.
CNG has made some progress since then, here's the kind of thing there is now:
https://steelheadcomposites.com/sites/default/files/2024-01/...