Tesla (and other electric manufacturers) are years away from building 3.5 million cars for the US.
If the vehicle is tightly coupled to burning petrol, that can't happen. Electric cars are merely an exercise in uncoupling energy source and energy use.
Then if you add on V2G, all of a sudden you can swing electricity demand +/- 20%. Combined with overprovisioning, this greatly mitigates the disadvantages of intermittent renewables.
I don't really see how we get to 100% renewables without it, and it makes sense to pursue both simultaneously.
On the other hand, almost all charging happens at night, which is a time of low demand on the grid. And delayed charging (combined with time-of-use rates) to move off of the 7 PM winter peaks is widely available. So even without v2g, vehicle electrification has worked out great on the grid so far.
This was for one of the big-3 German automakers and the company running a significant portion of Europe's energy grid.
It's still a while off, but it is a serious project with the intend to get to market. I'm no expert on the grid side, but if I'm not mistaken, the need just isn't quite there yet because the grid have been able to accommodate current renewable production levels.
My point was more as far as where Gov funding should be prioritised given their relutance to throw funding at new generation and rely on market investment while providing incentives to buy electric vehicles - though for Telsa that will be gone soon enough.
2b would pay for ~3.4GW* of hydro, ~1.2GW* wind or ~700MW solar* but only subsidise 400k EVs (avg 5k tax credit per vehicle).