Fusion or fission for energy, IMHO. I'm bullish AF on the hybrids China is working on.

None of the other options stand a chance, not even solar on Luna's poles. Too heavy to import, too capital-heavy to build capacity in situ.

Fission is a much easier challenge - but you need high-grade ores. On Earth, that requires hydrothermal activity. Mars is almost certainly a yes. Ceres just possibly. Europa and Ganymede have ice diapirism and fractional crystallisation from brines which should work even better.