Take the Kardashev Scale with a pinch of salt; it is not a realistic prediction on how extraterrestrials or future humans would act (how could we possibly know?) but it is a good way of highlighting energy consumption. A type I civilisation is one that harnesses all the energy available on a planet, Earth has about 1.74e17 watts apparently. A type II civilisation is one that uses all the energy of a star i.e. one that can build a Dyson sphere of some kind. A type III civilisation is one that builds a Dyson sphere around every star in a galaxy. Anything more than that is a civilisation that Dyson's galaxies worth of stars.
This is just a thought experiment though, it is not to be taken as gospel or prophecy.