Dyson-Sphere Energy Harvesting Around Black Holes: Feasibility for Type II/III Civilizations and Observational Signatures

To the point

Freeman Dyson’s idea of a megastructure around a black hole would harvest energy from the accretion disk to power a Type II civilization on the Kardashev scale, because Hawking radiation is far too weak and cosmic microwave background harvesting is insufficient, while a Type III civilization might favor disks around intermediate-mass black holes, all of which face major engineering and infrared-detectability challenges.