Black hole as the ultimate energy source, Ibrahim Semiz, Am. J. Phys, 63(2), February 1995
We point out that baryon number violation is necessary for significant matter to-to-energy conversation, which suggests that black holes may be used for this purpose. The classical mechanism for this is the well-known Penrose process. We describe an alternative mechanism, which is superior because the black hole acts like a catalyst and does not need to be rotating. The energy extracted via the Hawking radiations, i.e., the process is quantum mechanical.