You can look at coal, oil, gas as form of compressed solar energy, because all of them have biological source, stored millions of year ago. It's just burning coal, oil, gas has nasty side effects.
reply" Volcanic coal-burning in Siberia led to climate change 252 million years ago.
Extensive burning in Siberia was a cause of the Permo-Triassic extinction " https://www.nsf.gov/news/volcanic-coal-burning-siberia-led-c...
What about nuclear?
replyFuel was created by the explosion of supernovae, still solar but not our sun.
replyBy that logic, all of the Earth and the moon were once parts of stars, so tidal and geothermal are also solar.
replyWhen people say "solar energy", they are usually referring to first order solar energy, directly from photons, not second or third order solar energy after it has been trapped into other sources of potential energy.
If it's not our sun then it isn't solar.
replyProbably neutron star collisions, actually.
replytiny insignificant amounts
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