So largely I believe the plan is to use microwaves to send the power back to earth so you don't have to have anything processed in space. This would usually involve ground stations that would receive the power.
Nevertheless -- finding ways to move refined products around that embody a huge amount of energy is the traditional way to approach this problem.
And anti-matter, if you could package it, is an obvious example....
Not really. The biggest difference between a panel on Earth and one in space is the space panel is illuminated 23 hours a day. So per panel you're getting 2-3x the illumination over the course of the day.
The drawback is even at the absolute cheapest pie in the sky Musk estimates of cost to orbit ($10/kg), a space solar panel is orders of magnitude more expensive than a ground panel. You could just deploy 3x the number of panels on Earth for 3x the price vs deploying in space at x\^3 the price.
Even with the near constant illumination of panels in space the losses from RF conversion, free space losses, atmospheric losses, and RF rectification eliminate a lot of your power gains. For those losses you also incur significant costs. So SBS is kind of a lose-lose problem. Every technology that would make SBS more practical could be applied on the ground for a tiny fraction of the cost.
Small nitpick, but as a GEO satellite navigator I want to point out that the solar panels are in sunlight constantly except for "eclipse season" around the equinoxes. During eclipse season it can be in shadow for about an hour.