That is the total energy of a Kg matter according to E=mc2, if I'm not mistaken. How exactly are you planning to convert that matter into energy? Do you have a Kg of antimatter laying around your house?!
Photons are their own antiparticle, so this is not an issue.
Photons are the means for transfer for all energy sources at some level, so using that as a comparison for the actual generation method seems a little pointless.
Sunlight: 1.6e-6 MJ/m^3
(I do actually think solar will be the most useful energy source going forward)