You could use a generator. You could also use a steam engine to power your car. But most of us prefer the cleaner, safer, more efficient solutions :)

Wouldn't you agree that replacing fossil fuel based generators with a cleaner and cheaper alternative is worthwhile?

Not exactly a fair comparison, and dodging the point. Use a hydrogen generator if you prefer. Or a battery for that matter (as indeed our cars are headed). Point is it might be easier to be self-reliant (calculated local storage) than contrive a secondary power delivery pathway.

I can't imagine generators that are used to accommodate intermittent power loss would contribute materially to overall carbon emissions.