>galaxy. I think I got this from Hyperspace by Michio Kaku
In Kaku's VISIONS, he cites and uses the analysis by Nikolair Kardashev and Freeman Dyson (first popularised by Sagan, I believe, in THE COSMIC CONNECTION [1975]).
Type I civilisation masters all the energy available on a single planet. (So we're still Type 0.)
Type II masters a star - using a Dyson sphere, for example.
Type III exploits groups of stars, perhaps a whole galaxy.
Kaku conjectures Type IV, which plays tricks with wormholes and can escape the death of this universe by tunneling to another.
Damien Broderick