So, um, where is the power coming from? Are we getting something from nothing, here? It strikes me that this is a bit like Maxwell's Demon, cleverly creating order from disorder which can then be used to generate energy as the system moves back to disorder in a controlled fashion.

The amount of power generated on a tiny flake of graphene may be small, but there is probably some optimal arrangement of graphene fillaments or strips in a 3D space filled only with vacuum in which to draw on this effect, which in aggregate may be sufficient to basically draw useful amounts of power from the void.

Wouldn't that be something? If there's one thing this universe has got in abundance, it's space.