There's a myth or conspiracy theory floating around that the National Grid can't supply enough power if everybody switched to electric cars. This myth can be exposed by a very simple calculation based on facts:
There are 38.4 million registered cars
The average power consumption is 12KW (300Wh per mile) for electric cars while in use.
Energy consumption of electric vehicles cheatsheet. Quick reference for all plug-in hybrid en full electric cars.
ev-database.uk
The average annual mileage for cars in the UK is 7600 miles
How much ground does the average British driver cover each year? We've run the numbers to understand how typical mileage changes for purposes like commuting and business, as well as differences between petrol and diesel cars.
www.nimblefins.co.uk
335TWh were generated in the UK in 2018, though it was much higher in 2005, where it peaked at about 375 TWh.
The amount of electricity generated in the UK last year fell to its lowest level in a quarter century, Carbon Brief analysis shows.
www.carbonbrief.org
Calculation for total power consumed if all registered cars were electric:
300Wh/Mile x 7600miles x 38.4 mil cars = 87.5TWh
Percentage increase in electricity required would be
87.5/335 x 100 = 26%
In the future, you have to consider population growth trending up, car usage trending down, changes to energy usage (reduction programmes) and changes to power generation capacity. Energy usage reduced by about 10% in the last 10 years (40TWh), which is half of what would be needed. It's conceivable that there could be another 10% reduction in the next 10 years.
In summary, I don't see a problem.