In a 2 or 3 years all 450.000 model 3 tesla (and probably more) will hit the road and start making an average of 16.550 miles per year. Considering :
this will translate in around 2.5 Tera Wh/year more consumption on the electric grid. Let’s say that in 5 years 10% of all new cars sold are electric. We’ll have an extra 10 TWh per year to reach 1% of all electric consumption in US (in 5 years) and this will just be around 1% of the total number of cars on roads in US. So 1% of electric fleet equals 1% increase over total electricity consumption.