Energy limits on the Penrose process

If a body in the vicinity of a rotating black hole breaks apart into two or more fragments, then under appropriate conditions the rotational energy of the black hole can be used to enhance the energy of one of the fragments (Penrose process). Wheeler and others have suggested that the Penrose process could serve as an energy mechanism for jets. In this paper we derive strict limits on the energies which can be achieved by the Penrose process. It is shown that in no case can one obtain energies which are greater by a significant factor than those which already could be obtained by a similar breakup process without the presence of a black hole. Subject headings: black holes - rotation, stellar