I think, as I understand it, the energy for Hawking's radiation ultimately comes from the mass of the black hole. That is why it is thought that a smaller black hole would shrink and finally explode as it no longer has enough mass to accelerate stuff to C. The paradox is one particle of the pair escapes and one enters the event horizon, yet the black hole loses mass (equal to the mass times velocity of the escaped particle. I don't understand why).
Hawking's radiation may have been observed in collisions between gold nuclei at the Relativistic Heavy Ion Collider (RHIC) . I do not understand this article by
Dr. Horatiu Nastase enough to determine this. Work from the Large Hadron Collider (LHC) should shed more light on this subject, in the next year or so, maybe.
It is a great time for astrophysics!