I remember my Dad had a Commodore in the 80s that ran on CNG.
What a gutless piece of junk....faded lemon yellow too with sticky hot vinyl seats......
Maybe LPG/CNG to power turbines for greater range to charge batteries but the internal combustion engine has too many working parts and will be redundant in an electric future.
End goal for this revolution is:
Sun>Solar Panel>Battery for Storage = Decentralised Freedom
Habitation/Transport/Infrastructure a closed system powered directly from The Source.
Or maybe a Hipster Revolution Citroen 2cv powered by sentimental wishful thinking and organic free trade alfalfa sprouts........
.....what a beauty....