It’s really all about portable energy. And so far anyway, nothing has come close to petroleum type fuels. Battery operated land vehicles are quite heavy, except for Aptera, which is a three wheel solar cell covered vehicle that claims a 1,000 mile capacity and a 40 mile a day recharge if parked in sunlight.
But given the persistence of these inventors, something better might occur…as their methodologies are based more on science than alchemy. 