Something to think about - utilities may have incentives for EVs now, because there's little demand, and the benefits are clear. In the 20's / 30's, fossil fuel use was also highly encouraged over animal power. The problems didn't come till everyone switched over.
In my province, we're lucky to have (near) 100% hydro "clean" power; generation capacity is also not a issue. What is an issue, however, is the distribution grid and substations.
We have a lot of aging stations, and seriously aging underground grid. Some neighborhoods are maxed out in terms of power density (how many circuits we can run down a street). Couple that with a mass influx of population, I doubt we could keep up even if 50% of families goes EV.
In theory, everyone charges over-night. But in practice, a lot of people needs to get somewhere after work, and will likely plug in their cars during peak demand.