Its most about peak loading
There seems to be a lot of concentration about how much energy everyones needs and how much renewables can contribute to that. However the big big issue is peak load. If your system cannot cope with that you are busted.
It is all very well having micro turbines, photovoltaic panels, etc etc, but if they cannot deliver the peak loading when everyone gets up from Eastenders to make a cup of tea, your problem is not solved.
All the renewables suffer from the same major problem, you just cannot just wind them up instantly to produce more power. You could have massive over production capacity to cope with the peak loads, but it would mean covering a fair proportion of the whole of the UK with wind farms for example. Then there is the tricky problem of when there is no wind - and the same goes for most renewables.
A mix of renewable sources plus huge power 'instant on' power storage to cope with lack of renewable energy avilable when the demand peaks is the only way to make it work.
The only sensible renewable technology I have ever seen proposed that could beat both the huge demand and the 'instant on' power problem, was to build a whole series of tidal power generators around the UK, with a large mix of wind turbines / Solar panels / renewables to feed power into them. Building tidal generators around the UK would alleviate the 'only twice a day' problem with tides, and the additional power feeds would assist by pumping water higher (or lower), when excess power is available. Basically use tidal as both power generation and power store.
Of course you have got to build enough of them spread around the coastline (£Billions?) and build the huge number of renewables needed (£Billions?). You will probably still need nuclear/fossil fuel generators because no renewable mix will supply enough for everyone all the time everywhere.
Then there is getting over the objections of the 'save the lesser spotted warbling ground worm for future generations to enjoy' brigade. I visited one guy who proudly show me his brand new solar heating panel and then listened to how he was applying to the council for a reduction in his council tax because the nearby wind generator has ruined the value of his house. There is a motorway between him and the generator and is built on an industrial estate. I told him that I could not hear it over the sound of the cars and thought it looked quite nice compared to the industrial buildings and could not see how it had affected the value of his house - let alone ruined it.. I must have upset him or something because he has not spoken to me since. Ho hum.