So this is basically how satellites already work, except the energy would be sent back to Earth through microwaves. What would be the room taken on Earth?
Interestingly, the article also suggests that this could be useful for remote applications that would have difficulty getting supplied with diesel or other fuels:
"An advantage for the military, as well as civilians,
would be that they could build receivers at remote
operating bases and locations where it is
logistically difficult and incredible costly to
deliver diesel fuel."
However a true disadvantage to arrays would be, a geostationary energy farm would transmit optimally to land directly under it - the air is thinnest. Steering the laser to remote places would lose efficiency as it traversed oblique slices of atmosphere at odd angles.
For the original plan, there's no actual requirement to steer the beam. A station isn't so large that one city couldn't consume the whole capacity. So still a reason to build the thing.