Seems like a poor superpower, if you don't mind me saying, but an intriguing one atleast. Or atleast different. I suppose you'd get power relevant to the solar power, which I presume would revolve around fire/heat etc. I was thinking a light beam, not sure how that would manifest itself in terms of being used by the person, but if it's a superhero then the person could just lift their hands and be able to fire it. Another could be the ability to light up any area at night, with a reducing energy, which is useful without being particularly exciting.
If you want realism, then you'll have to go to heat and maybe a bit of a glow, especially at night. Enemies trapping them could potentially hold them prisoner under UV lights until they explode.
Honestly... anything involving energy or power you could turn into some kind of "beam" type of power. Because as long as you have energy/electric power to use, you can turn it into some kind of weapon. Remember in Ironman (the movie), those little stabilizer things that came out of his hands were originally used for flight and not as a weapon. But... again it's energy directed in a direction. And in comic book world you could explain away things a lot easier than in the real world. Just say that "oh, he can directionalize the energy into a beam like cyclops from X-men".
I gave the Ironman example in my last post. A beam of energy pointed downward in theory could propel someone into the air. You might get some hardcore nerds that find some scientific reason for it to not work, but in all honesty you are already giving him super powers already so it isn't much of a step to say that the solar energy could operate like a jet pack or any kind of rocket propelled machine. Edit: since I'm making so many allusions to Ironman already... Ironman's abilities are all based off of the fact that he has a giant energy source powering that suit. So in the same way... "solar energy man" could in theory have a suit that he powers with his "solar energy channeling" abilities that can do all kinds of crazy shit. Although, that is pretty close to what Ironman does so readers might see the similarities and call you out for copying that too much. However, I'm just illustrating different ways that power can transform into flight.
1- It would be of great value, here in the UK, to the National Grid. 2- Being that energy prices are going through the roof here, it could help to bring the prices down. or It could make the super hero 'super' rich, by cashing in on his powers - then of cause he would be the antagonist as apposed to the protagonist.