>Looks like we managed to replace 40% of fossil fuels in two decades, without much inflation (almost in line with countries who did not deploy renewables):
Just to get our terms in-line, renewables typically include hydro-electric. Hydro-electric is a great power-source if you have the geography for it. My province of Ontario, between Nuclear and Hydro, pretty much only derives 5% of power from fossil fuels. The problem is, there aren't any more places to dam to generate hydro. So that's done.
And yeah, there is a ceiling on how much wind/solar you can handle as a percentage of your power-mix because you need to rely on base-load to bridge the intermittency of wind and solar. I don't know what that percentage is ... maybe it's 40%, maybe it's 60% - but it's going to be somewhere in that range.
>We'll see how UK continues its transition, but I see renewables becoming cheaper while nuclear keeps rising.
It doesn't matter if they are free! You're not replacing fossil fuels with wind and solar because you still need to run your economy when the sun isn't shinning or the wind isn't blowing. You'll need base-load from somewhere else. Nuclear is actually terrible for that because it can't spin up and spin-down on-demand. Hydro and Natural gas are perfect for that, but like I said, if you don't have the geography for hydro, you're stuck with natural gas.