So are fossil fuels, and pretty much everything else on earth, including life itself. Carbon-based fossil fuels are simply very old plants which have stored and

So are fossil fuels, and pretty much everything else on earth, including life itself. Carbon-based fossil fuels are simply very old plants which have stored and concentrated solar energy. The only non-solar non-fusion energy I can think of is that which comes from the earth's core, geothermic. And even that is believed to be powered by nuclear fission.