Well, any hydrogen car that combusts the Hydrogen with atmospheric Oxygen fits this only if the Hydrogen is created by electrolysis of water. It will be very in

Well, any hydrogen car that combusts the Hydrogen with atmospheric Oxygen fits this only if the Hydrogen is created by electrolysis of water. It will be very inefficient even if the Hydrogen comes from solar/wind/wave power as it will also lose efficiency due to the Carnot thermodynamic losses. https://en.wikipedia.org/wiki/Carnot_cycle https://en.wikipedia.org/wiki/Carnot_cycle If we reach a high enough order of solar/wind/wave power production we would be better served by electrolysing water to Hydrogen, which is combined with oxygen in a fuel cell in the automobile. Best practice is to steadily create electricity and store a portion in Lithium batteries - for the starting surge, using the steady fuel cell production for travelling at ~100-120 Km/hour - this reduces the size of the fuel cell needed. If you run fuel cells at high power density = low efficiency, low power can be in the 75-90% range - this is increasing steadily with research. Compressed hydrogen should be avoided as the cylinders are large and under high pressure and waste space. Crystal clathrates have the ability to reach about 50% of liquid Hydrogen density. Liquid hydrogen is also good for long haul trucks, with H2 station on interstates. Trucks can be defueled when off duty at H2 stations to deal with the Hydrogen boil-off losses.