So far Jimmy T is correct in that antimatter is more of an energy currency than an actual energy source. To produce even the smallest microscopic quantities by today’s methods is far too energy intensive. You have to use a tremendous amount of energy to accelerate a conventional proton close to the speed of light before striking a target. When it does, all that energy used to drive the accelerator and cause the proton to become more massive is enough to create another whole entire proton …… the anti – reversed mirror image of it, that is.
But if somebody has found a more energy efficient way to convert conventional matter, I would really love to hear about it. That would really be an exciting breakthrough ! ! !