Black holes are almost the perfect battery. Small black holes decay very quickly, a black hole the mass of, let's say a small mountain, would decay almost imme

Black holes are almost the perfect battery. Small black holes decay very quickly, a black hole the mass of, let's say a small mountain, would decay almost immediately, releasing it's energy as hard gamma via hawking radiation, whose energy could be captured and used via multiple processes including some sort of sterling engine/photovoltaic mechanism. If some how you were able to create a small "artificial black hole" you could just feed it mass, any mass, and it would be converted directly in energy, as if it were a matter/anti-matter reaction. At least, that's what my two semesters of modern physics and latent desire to be eventually be a sci fi author tell me. I am reasonably sure nature has some sort of small print that kills my awesome idea, like requiring 100x to create said black hole than energy released, bleh nature. IANAP.