"Meanwhile - feel free to replace your car with an electric one, because from all the pushing from politicians and "energy experts" you'd be forgiven for believing that the electricity they use just appears out of nowhere and doesn't have to be generated first......"
Power generated by renewables is intermittent in nature and hard to store. That's one source. The second (existing and well known) source is the large gap between capacity and demand over night. They already sell off-peak power cheaply in an attempt to get people to use it. You don't need any more generating capacity in order to cope with (IIRC) 30% of the country's traffic being electric powered.