Ok - as usual I'm going to complicate things. Electric cars use less energy from all sources than carbon fuel cars, irrespective of source. Electricity consumption has been decreasing rather than increasing since 2005, capacity is increasing and renewable use is increasing. In Scotland about 98% overall electricity is renewable - though this is a bit misleading as it exports quite a bit of this and imports during higher demand. So lets get this absolutely clear, this is not a zero sum game, more electric cars will not cause power limitation from other sources. There is a need to replace and increase generating capacity from renewables and nuclear but that is primarily to move away from gas fired electrical power, which is a much bigger issue.
UK consumption is down drastically, mostly from getting rid of most industries.
So generation capacity must be down.
As we've gone from generating all our electricity, in the days of heavy industry; before Thatcher; and before the multiple subsea power cables. To now only generating, on average around 80% power needed in the UK ourselves. But can only manage that when it's windy, the percentage drops for weeks, when there's a persistant high pressure.
At this moment, interconnectors (imports) make up 15%, mostly from France (nuclear), and Norway (hydro).
https://grid.iamkate.com/
Our last three backup coal fired stations, previously semi-mothballed, have now all been scrapped. So don't be surprised when the lights start going out, during a cold winter (when EU is short in supply) that coincides with high pressure around the UK.
In some countries, their network planning, is now required to factor in 'wind droughts'. In the UK, they just hope (we'll be able to import enough).
An interesting fact (fom the last years figures available), was that in under a year, £1 billion was paid to UK wind farms, to STOP generating. That cost, to 'balance' the grid, comes from our standing charge payments.
New planned wind farms, (approved + applications) would increase wind generation 10 fold. Guess what will be happening to our standing charge. There's little chance of being ever able to export the potential surplus, and apperantly no consideration.
Some calculations, suggest that UK gas fired power stations, when running on imported LNG. Are more carbon polluting than modern coal fired stations. If transportation emissions, which are much higher than locally sourced fuel, are included.
That's quite similar to how the UK, manages to have low emissions, from wood chip power generation/ heating.
In N.America, carbon emissions are only counted where the wood is burnt. While in the UK, emmisions are only counted where trees for burning, are felled. So a tree felled there, then burnt in UK, produces zero counted emmissions!
Unlike a tree, grown in UK, that doesn't need to be shipped a long distance.
