The UK is a vast country, the idea that wind and sun are lacking in all of it seems a corner scenario. Plus it could always pay/exchange electricity with the rest of Europe.
This is just the brexiters bending backward to not be part of Europe.
It feels like a socially incapable person leaving a party where (s)he was wanted and esteemed because (s)he has deep trust issues.
Or more likely, because (s)he can't sit at an Arthurian round table of equals. Wishing to be the top dog or nothing.