> It'll be difficult to power a grid with 100% wind and solar so that's all you hear. But on the flip side, it'd be quite straightforward to power the grid using 90% renewables using the existing plants for the last hard 10%. It'd be both cheaper & cleaner! Why the heck aren't we celebrating that?
Solar, hydro and wind when you have them, nuclear when you don't, gas when you don't have nuclear and coal when you don't have gas. It is really quite simple. And the best bit is that you can have your solar and wind installations up and running before the ink is even dry on the kind of permit and investment required for a nuclear plant and it is much cheaper to boot, as well as decentralized so far more resilient and friendlier to the grid (assuming the grid is well designed in the first place, which isn't always true).
And 'in a country' is the wrong level to be thinking at. You should look at much larger areas than that, and across both longitude and latitude.
When you say this you need to also talk about how much it costs to build enough energy storage for solar to become some given percentage of grid power. There is probably some % where it stops being cheaper than coal