No, there should not be taxes on solar power, if only to promote more individuals switching to unlimited resources like solar power. In addition, solar power does not use any of the "grid", that is the public infrastructure on which electricity is carried. Thus, solar power should not be taxed for this reason, either.
Why the hell should the people pay taxes on solar power? The government and industries don't own the sun. For example, if I flat out buy a off-the-grid solar system for my home than its mine. I already paid the taxes when I bought the system. Why the hell should I pay anyone for taxes on the use of my solar power?