Hydroelectric?
Well ... the earth’s gravity is in play here. No clouds would spread the water from the sea to the air, to fall at higher elevations for hydro — IF NOT for the heating and cooling caused by the sun.
It all traces back to solar sources.
Hydro is solar. The sun evaporates the water that makes the rain that makes the rivers flow. Nuclear is not solar. oil/gas is not solar because in spite of people calling them fossil fuels, there is considerable evidence that they were captured from the nebula from which the earth and the rest of the solar system was formed. Coal is fossil.