Having a look at gridwatch.co.uk now and then is very telling.

Electricity generation is mostly gas and coal has been reactivated. As I'm typing coal supplies 4% of electricity, wind 3%.

We're hitting a key issues with renewables like solar and wind. This is winter in the UK, we're not going to get a lot out of solar and if we hit a calm patch (there's been little wind lately) we're pretty much screwed.

Precisely why we need grid storage.

The UK actually has some of that (pumped storage, mostly). But not enough to last long enough.

Or reliable sources of electricity.

Not sure storage would even save us in the current situation.