Let’s look at some facts.
1gigawatt = 1 million kilowatts
there are I think about 10 million cars in the uk. All electric is the dream
if just one million of those now plug in to their home charger at 7 kilowatt to charge up overnight that is 7 gigawatt they will need.
where will this electricity come from, at this moment we are importing electricity to meet our needs
Whilst your Maths is correct your assumptions are erroneous.
There’s over 30 million cars in the county, more when when you include light vans.
There are now well over 1m EVs in the country, nearly 2m when you count plug in hybrids. As you can see from current grid statistics, there’s nowhere near an extra 7GW of demand out there. And that’s because not everyone charges overnight, and very very few charge every day,
The average car does a little under 7000 miles a year, which with pessimistic kWh / mile economy is 2000 kWh per year. That‘s an average of 45 minutes charging per day per car at 7kW.
Scaling up, with 30 million EVs on the road (which won‘t happen until the 2040s at best), if you assume that 2/3rds of all charging is at “night” from 9pm to 7am the next morning that reauires an
average of around 10GW extra power from the grid each night.
As it happens, with the exception of perhaps a dozen cold & windless nights each year, we already have 10GW spare capacity in the grid between 9pm and 7am. Within the next 5-6 years we will have another 10GW of wind capacity too (which will kick out an average of 4GW over time) plus a similar amount of Solar which will prove rather useful for daytime charging. We already have variable price charging and this will become the standard for the majority of EV users, who will typically charge when the wind is blowing / sun is out and cheap rates (when there is loads of cheap power).
There’s really nothing to worry about.