Well most likely this will be done when people go back to the moon. Meaning that once people build an electromagnetic launcher capable of launching the needed materials from the moon it will be extremely cheap to get these energy arrays up and running.
As a side note it will most likely be China that does this since they seem to have a plan to build a moon base which is step one for all this to work. Plus by the time they get to the moon Chinas fossil fuel consumption will be so great that it will most likely use up the better part of their supply and they will need the solar energy from space just to function at a stable level. Of coarse once all is said and done they will be in the best position to sell extra space energy to the rest of the world and since space is large there will be competing countries with competing space arrays that will eventually drive competition and lower costs.
As a side note it will most likely be China that does this since they seem to have a plan to build a moon base which is step one for all this to work. Plus by the time they get to the moon Chinas fossil fuel consumption will be so great that it will most likely use up the better part of their supply and they will need the solar energy from space just to function at a stable level. Of coarse once all is said and done they will be in the best position to sell extra space energy to the rest of the world and since space is large there will be competing countries with competing space arrays that will eventually drive competition and lower costs.