Electric vehicles are capable of being much more efficient when going from energy source (the sun) to actual work preformed. About three times more efficient than hydrogen. [1]

Your comment seems seems to me like a classic strawman. The electric power production is being decarbonised and more money is spent on renewables than fossil energy. [2] if you feed that energy to a battery car, you need less power production than if you feed it to a hydrogen car.

Hydrogen may provide a viable alternative, but it seems to me that the substantial infrastructure needed is going to be costly [1] and the electric infrastructure is well built out already.

[1] http://tonyseba.com/toyota-vs-tesla-can-hydrogen-fuel-cell-v...

[2] Overall, more than twice as much money was spent on renewables than on coal and gas-fired power generation ($130bn in 2015), the REN21 global status report found. https://www.theguardian.com/environment/2016/jun/01/renewabl...

But with both cases, something clean is at least possible. Solar/wind/stuff not invented yet, could be the source. Phase out the coal and you're done. When petroleum-based combustion happens in the car, you probably wont ever get carbon neutrality.

Well, if we are talking about not-yet-invented stuff, we might also someday have feasible artificial hydrocarbons or corn-fuel farms run with electric combines. Nether one of those would require a fundamental change in car design.

All I meant there was that it can be changed and blended instantly, electricity is electricity. Look how long it's taken to change sulphur, lead, ethanol, etc in the us gas supply. And this still requires work for the existing fleet of cars.

Solar, wind, hydro, geothermal, biomass. Maybe nuclear.

That's it. Don't go hunting for your something else, it's just wasting time. Nuclear, given lead times and more, is also quite possibly wasting time, though I'll allow some possibility it isn't. Long-term though, it's almost certainly highly problematic.