Presumably if your super-advanced civilization needed more energy than could be fused from all the matter in a planet, you would have to get it from a star.
Presumably if you are a super-advanced civilation, you would get power from what would appear to us mere primates as essentially thin air, in a fashion we can't even fathom.
"Any sufficiently advanced technology is indistinguishable from magic."
So a Dyson Sphere is inane, but energy from nothing isn't? Got it.