[thackney]

Per Kilogram yes. But the density of hydrogen itself is so low that per volume it is very small unless you compress it very much.

So you either have much less energy in the same volume, or so much pressure there is no way to intake air for combustion.

[bonedoc33]

Good point, I have to concede that one. I did not consider volume. However, The storage cylinders for compressed hydrogen are usually kept at about 70 Mpa (700 bars). I don’t kmnow if that is enough to make up for the density issue or not, but that is some serious compression. Also, the article said the tank contained supercompressed hydrogen. If 70 MPa is the norm, what is considered supercompressed? I couldn’t find an answer to that, do you know?