> Especially considering it'll take 10+ years for electric cars to be widely used by a significant fraction of the US workforce.
This is key, plus I think we're overstating how fast this will happen.
In 2016 we're still at sub 1% of all new car sales being electric, at 0.9%. i.e. for every 100 cars we're adding to our roads, not even one full electric car is added. Not to mention about half of the electric cars are hybrids.
Average age of cars is about 12 years. So if the 1:99 ratio is overturned say in a decade to favour electric cars (which seems ambitious itself[0]), it'll take at least another decade to phase out existing cars and see the fleet get replaced by new, mostly electric.
So 10+ I think is conservative, it's probably 20+.
Another thing to mention is that we can generate a lot more electricity with our existing capacity than we do. Why don't we? Because at night the demand simply isn't there. But with a software-based transport & fueling system that EV offer, a lot of this extra demand can be shifted during times of low-demand, without needing to install extra capacity, but rather just not taking as much capacity offline nightly.
Finally, I cautiously expect a shift away from personal transport and public transport, but towards semi-public/personal. i.e., I'd be quite feasible if you could hail a self-driving pod in 20 years, get in, have your destination set via whatever has replaced our smartphone (e.g. software assistent), and get out, paying automatically, a la uber today. The pod drives according to your personal wishes, but it's part of a shared public transport system. I expect this to make driving safer and more fuel efficient in driving behaviour, more efficient in terms of capacity (no more 4-seater cars full of 1 person, no more driving around with vacation-level storage that's mostly empty on 9/10 trips), more efficient in terms of size (lighter vehicles, less crumple zone required). This shift too may significantly increase the km per kwh spent in the next few decades.
[0] As for whether electric becoming the majority of car sales within 10 or 20 years is feasible... a little context: it must be noted that the US sold 96k electric vehicles in 2013. In 2016 it's 157k. Growth rates are a little under 18% yoy. If you'd grow at 32% a year, which is twice the annual growth rate compared to the past few years, you'd sell 2.5 million electric vehicles in 2026, annually. But the US sells more than 17 million non-electrics annually today, so you're still not making a huge dent. That's a shitty calculation of course, but it's some context. Typical forecasts predict something like 30% of new car sales to be electric in 2030. Again, that's new sales. About 8% of cars are retired each year, if you replace them by 30% electric cars, it takes about a decade after 2030 to even get to 30% of the actual car fleet to be electric.
So all in all, I don't really think the grid is the biggest challenge here, although there are obviously very large investments to be made.