You're mostly wrong about the coalification process as it relates to the carboniferous. There's many different types of coal, but the one you seem to be thinkin

You're mostly wrong about the coalification process as it relates to the carboniferous. There's many different types of coal, but the one you seem to be thinking of is hard coal (anthracite). The others are lignite and bituminous coal. It's indeed the case that the comparative lack of rotting during carboniferous contributed to the available biomass to turn into coal, but that sort of coal doesn't form without heat and compression. It's got as much to do with the earth being more geologically active at the time, and more low-lying wetlands. But coal is forming today from peat -> lignite -> bituminous coal -> anthracite (then eventually graphite). E.g. Germany's electricity generation was ~30% lignite burning in 2015[1], and those deposits formed mostly during the tertiary period. So you're five to six orders of magnitude off if you think coal hasn't been forming since the carboniferous. None of which is to say that these deposits are renewable in any practical sense. We can imagine digging them all up and burning them in the next 500 years, and then having to wait around the time since the T-Rex walked the earth for meaningful regeneration. 1. https://en.wikipedia.org/wiki/Lignite#Uses https://en.wikipedia.org/wiki/Lignite#Uses