Harnessing energy from renewables is eventually a zero-sum game: you can never generate more energy than the sun inputs into Earth's atmosphere, and every bit of energy we extract is no longer available for nature to use. It's not a sustainable practice if we assume that as a society advances technologically, it requires ever more energy per citizen (and no, the various green initiatives have not disproven that assumption -- they reduce energy waste, not energy usage).
Unlike renewables, fuel-based energy sources like nuclear (and coal/gas) do not reduce the amount of energy available to Earth's biosphere.
> you can never generate more energy than the sun inputs into Earth's atmosphere
This is 100% a feature and not a bug.
> It's not a sustainable practice
The very opposite. If we want to slow down climate change we need exactly zero-sum energy sources that do not release extra heat into the atmosphere.
> if we assume that as a society advances technologically, it requires ever more energy per citizen
Nothing in your claims indicates that is not possible to produce more energy using renewables.
> if we assume that as a society advances technologically, it requires ever more energy per citizen (and no, the various green initiatives have not disproven that assumption
The sun provides such ridiculous amounts of energy that we needn't worry about that limit for quite some time. Also, the assumption that we need more and more energy per citizen as we advance seems dubious. In developed countries energy use per citizen has been stable or declining for quite some time now.
Renewables don't compete with nature, there is more than enough energy from the sun.
It's in fact the opposite, the sun radiates too much energy, that's how we get to global warming when not enough gets radiated back into space. Using nuclear adds even more energy, renewables don't.
Unlike renewables, fuel-based energy sources like nuclear (and coal/gas) do not reduce the amount of energy available to Earth's biosphere.