A charging EV can draw 30-50 amps @220V, much more than a kettle…
If you want a harder problem, it’s electric building heat in cold climates.
That said my basic calculation for New Zealand is additional 50% is needed. Probably easy peasy if we get over lobby given how much existing hydro we have and capacity for sun and wind.
Using Chinese offshore wind turbine costs my estimate was 1/3rd of some major railway project cost we are considering…