Solar power

While called solar power, it is somewhat a misnomer as it merely means harnessing any form of light energy. Not only does this not necessarily refer to the Solar System, but it isn't necessarily even powered by stellar fusion - a white dwarf or accretion disk of a neutron star or black hole will also do.

For most, this is the primary means of energy generation in terms of raw numbers. This allows a number of stellar civilizations to reach ~26 on the OOME scale using 'simple' Dyson swarms. Gathering and harnessing this vast quantity of energy is the only means by which 'normal' civilizations can even hope to damage Regalia. While this is only a minor insurance against predations, storing energy for a possible conflict with a rogue cerevate gives some systems peace of mind.