Depending on the scale you look at, it could be.
On human scale, it is renewable because it will be there effectively forever as far as humans are concerned, and will not run out.
On universal scale, it’s going to be gone in not too long. The universe is about 14 billion years old, and the sun is about 4 billion, also roughly halfway through its life. Sometime in the next few billion years, the sun will transition to a giant and most likely eat earth, so all of the solar panels will be gone. Eventually, even the sun will die.
That being said, the technology behind solar collection could be adapted to differnt environments, and assuming we humans eventually leave this rock, it could be used on the electromagnetic output of other stars to generate power. And with the birthing of new state still happening, you could find a source of energy for the panels for a very very long time. So long that I’m not sure there are any solid theories as to what will happen to the universe. There is the possibility of thermodynamic equilibrium, at which point there wouldn’t be any stars, but I don’t think any life either, so moot point. Same with the big crunch and big rip, no stars, but no life.