UK electricity demand peaked in 2005 at over 400 terrawatt-hours. Demand in 2022 was around 325 terrawatt-hours, so there’s plenty of spare capacity in city grids to cope with a new peak.
There are some problems connecting the new offshore power generators connected with sufficient capacity to feed into the grid, but that’s a relatively quick and easy fix.
As you suggested in an earlier post, EVs are best suited as city cars, yet my brother in rural Somerset has recently bought a Renault Zoe and finds it perfect for getting around locally, and can even get to SE London on a single charge, or stop off at Fleet Services for a recharge and a coffee if suffering range anxiety. Change can happen quite quickly. Just look at how wind, solar and hydro make up a greater proportion of the UK’s power generation than coal and oil.
As for HGV’s, if Britain’s 7,200 miles of trunk roads (inclusive of motorways) had one lane of overhead power lines for a pantograph, HGVs could be powered and recharge sufficient battery to get to/from their destination on normal roads.
Self driving cars may in the future reduce people’s need for private car ownership. Already 46% of London households have no car, I can see that proportion may increase if people can quickly and easily summon a car from a charging point by app.