As opposed to potable power (moonshine)? This runs the gamut from firewood and grain to mini-blackholes, but pretty much skips fossil fuels.
3:30 One ton of TNT has a trillion food calories
12:38 betavoltaic battery
17:40 Quantum Plug Uncertainty
19:50 Biogammavoltaics — fungi that eat radiation!
...then on to anti-matter and black holes. My interests falls off at that point, but Isaac Arthur is a completist.