A kg of gasoline is about 40MJ. The speed at which the energy is released is the important factor, not the total energy.

Sure, and the speed at which a cloud of hydrogen-oxygen will release energy after ignition is very rapid indeed.

The theoretical maximum detonation velocity of a hydrogen /oxygen mixture is significantly less than TNT.

You're also not going to get anywhere near the theoretical maximum detonation velocity if it ignites because of a leak.

My point is comparing hydrogen to TNT is very misleading.