The world needs a new source of energy, an unspillable source.

Here is a question about the energy conservation in the Dirac sea model?

In the Dirac sea a particle-antiparticle couple can be created,
and then annihilate in such a short time that the energy conservation
principle is not violated.

Say I have two photosensitive parallel plates placed in vacuum, and
distance between them < < their size . If I wait for an infinite time, a couple of photon-photon will be created (traveling to opposite directions) between them and each of them will react with one of the plates. How exactly is the energy conserved then?