1 liter of petrol, when burnt with air produces 3 times the energy as 1 liter of liquid hydrogen.

Uh oh!!

uh oh!!! would you have a link to that info , so that I
can read it myself?

I would presume that you are ignighting the hydrogen in a low or slow oxygen environment.
since the air only has a 21% oxygen content the liquid hydrogen would need to WAIT untill more oxygen
is sucked in before more hydrogen would ignight causing a slow burn or explosion.

uh ohhh !!!

I would think that when people performed test to determine the energy content in the two fuels
they would have thought about this.
and they probabbly did , thats why hydrogen shows as 140 MJ and gasoline shows as 44 MJ per kg

3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.