That's just nitpicking. There is thermal power generated from the electromagnetic power from the sun and GP is right that a solar panel turned off will be hotter than one turned on.
And if that was the original poster's intent, I apologize for nitpicking. My impression was that the use of "generating power" in the given (open circuit) context suggested a fundamental misunderstanding of the behavior of solar cells in this situation on behalf of the poster, and thought I might clarify; and perhaps even if the original poster understood this already, someone else learned something.
