2,359 kWh per liter of liquid hydrogen
The tank is a main problem with the hydrogen. Hydrogen boils with -252,76 degrees Celsius and in a liter contains only 2359 Wh chemical energy.
Modern diesel engines get out of a liter of tank volume about 4.5 kWh of mechanical energy. However, only about 1.2 kWh can be taken from a liter of tank with liquid hydrogen. In addition still there comes the thermal insulation of the tank, so that the liquid hydrogen remains chill.
My first car was a used VW beetle 1500. A quite gruesome guzzler. In a long holiday journey all 2.5 hours of compulsory break in an expensive highway gas station. 40 liters of tank and 11 liters/100km for always top speed on the highway. Ridiculous 125 km/h according to the car papers.
My Seat Alhambra TDI has with cruise control on 125 km/h about 6 liters of consumption and with the tank trick which fill in the air bubble in the tank, about 1,400 kms of reach.
But it is not only the tank in the car. To transport the same amount of mobility to the gasoline stations are 4 times more tank trucks necessary. The limiting factor is the volume of the hydrogen and the thermal insulation.
Compared to diesel or gasoline, a fuel station needs 4 times bigger tanks for the same amount of mobility delivered to the cars. No more simple double-walled steel tanks. Super heat insulated tanks to take up the liquid hydrogen. The chill engines which hold the stored fuel on less than-253 degrees, so that he does not evaporate. An emergency electricity supply for every gas station, so that with an electric power failure, the evaporating fuel must not be burned off, but again liquefied comes back into the tank .