Nuclear/geothermal aren't.
And fossil fuels are solar very indirectly - they're solar from many million years ago; biomass/wind/hydro are solar quite directly - it's just this or last few year's solar.
Well, unless I'm totally confused, the uranium/plutonium were generated by solar fusion.
Also, most geothermal heat is generated by radioactive decay (some is residual gravitational binding energy from earth's formation) , making it indirect nuclear fission power, (and thus ultimately solar power, if you want to be unpleasantly technical.)
We have a sample of one modern human civilization, but there are some hints on how likely it was to happen.
Major types of hints are:
Data for:
Data against:
To me it looks like life, animals with nervous systems, Upper Paleolithic-style Homo, language, and behavioral modernity were all extremely unlikely events (notice how far ago they are - vaguely ~3.5bln, ~600mln, ~3mln, ~200k or ~600k, ~50k years ago) - except perhaps language and behavioral modernity might have been linked with each other, if language was relatively late (Homo sapiens only) and behavioral modernity more gradual (and its apparent suddenness is an artifact). Once we have behavioral modernity, modern civilization seems almost inevitable. Your interpretation might vary of course, but at least now you have a lot of data to argue for your position, in convenient format.