This is some of the most retarded shit I've ever heard:
https://en.wikipedia.org/wiki/Dyson_sphere
This would probably require all the mineral resources from dozens of systems. And take millions of years to build. This is pure fantasy, yet some scientists think this is a real possibility. Any civilization capable of such an engineering feat, would have to be an interstellar civilization, and would have most definitely came up with more viable, alternative energy sources, and they wouldn't need something as crude and costly as a 'Dyson sphere'.