Using hydrogen to power cars how green is it.
You use electricity to generate hydrogen then transport it to fuel stations to be put into cars, which uses a cell to convert it to electricity to drive the electric meters.
Only at best 60% conversion electricity to hydrogen to electricity might just as well use EVs.
Note currently H2 generated from oil is the most effichant so still using hydrocarbons.
Hydrogen as a fuel does have potential, but as you say its hampered by its production distribution, and storage costs. But by the same token so do petroleums, and it's energy and financial costs of extraction, refining and the transporting side of things that are so often forgotten when people make comparisons between fuels.
At least with Hydrogen (H2 ) the raw materials are readily present, but the costs of electrolysis, storage and distribution per litre are presently higher than petroleum. This could well change as more is produced with economies of scale, and improving technologies.
However its the way H2 can be used that might make more difference. Although JCB has developed an ICE that burns H2 , they can't get away from the inherent inefficiencies of internal combustion.
The very best ICE have only just about managed 50% thermal efficiency, and that is under strictly controlled conditions. most commercial diesels are still only about 20 to 30%
and petrol a few % less. - And of course that only applies when they are doing real work. Its when they are idling off load when the efficiency of fuel in to work out drops through the floor.
So the very best way of using H2 is in a fuel cell where it only produces energy on demand, and using it to power an electric motor.
H2 does have some advantages as a means of storing energy, Once the H2 has been created and stored - assuming the containment has no leaks, then you can get out exactly what you have put in regardless of how long its been stored. And the containment can be used many times over.
By comparison All batteries that i'm aware of do have some self discharge so the charge does diminish even if its not connected to anything, and many battery formulations have a limited number of charge and discharge cycles which degrades the charge capacity.
There is no single technology that provides a universal solution to a transport needs or want's I am certain it will need a range of alternatives to replace all systems that previously relied on petroleum ICE.