Why 5%?

It is doable and people do it.

Here in Australia anyway.

You just need enough Solar, enough battery, and controls on your power load.

Not saying it’s easy or commonplace right now, but if you really want to, you can go off-grid!

In Australia at least.

I agree it's doable by some rich and Niche individuals, but it's not socially scalable, let alone efficient.

Of course with enough money you can put in three times the panels you need on average to account for winter days. Similarly, you could put in a week's storage battery in case a nasty storm comes through.

That's basically it :-)

But you can, if you want to...