Question

how much energy in black hole

Answer 1

black holes are created by certain dying stars and when the star runs out of nuclear energy gravity wins out and the star implodes. An entire star’s mass collapses down into a smaller and smaller volume of space.
However, black hole can have energy. One type that comes to mind is angular kinetic energy. This is the energy that a spinning object has - in this case, a rotating black hole (see also Kerr black hole and Kerr-Newman black hole). Black holes can also have translational kinetic energy - the energy of an object in motion. Also black holes have gravitational potential energy - potential energy due to gravity - and black holes with electric charge can have electric potential energy.

hope this helps

Answer 2

While no energy can escape from beyond the event horizon around the black hole, energy is released from the material as it falls in. Accretion onto a black hole is the most efficient process for emitting energy from matter in the Universe, releasing up to 40% of the rest mass energy of the material falling in.