How does this fit in with that renewable energy ( wind and or sun is unreliable - can be non of both types or one type for days at a time AND solar is only available for a 4-6 hours a day ) ) ? It seems massive storage is needed.

Not that massive. At a country scale, wind blows somewhere all the time. Overall you can get 30%+ utilisation per turbine. And newer projects only get it better (the higher you get, the more consistent the wind).

But it's not a surprise you'll need some storage. There's lots of research available with estimation for various areas.

Sometimes I wonder if you can have a central planned economy without sacrificing the democratic process.

EU comes close. There are a few programs that apply to all countries inside without really breaking the local government rules. (Although that's still typically incentives rather than forcing companies to do things)

As opposed to capitalism? Capitalism is not significantly more democratic in my opinion.