What energy sources do we have that don't ultimately derive from either solar of radioactive decay? Residual heat from object formation perhaps.
> solar of radioactive decay
We can do fusion, but given the only large sources of that are fusion bombs and nobody wants a bomb-based power plant… :P
Gravity, just ask Jupiters' Moons.
> solar of radioactive decay
We can do fusion, but given the only large sources of that are fusion bombs and nobody wants a bomb-based power plant… :P