Not necessarily, it could very well be a PR trick. Going solar is trendy so they may have done it to get some press.
It pays off but maybe in extra iPhone sales /brand building
I like to think PR and costs weren't the only drivers of this...Steve Jobs was quite the hippie capitalist, so I like to think he instigated a move into this space :)
Dude, if Apple is liked and their brand loved even more, that $xxx million spent on solar there is nothing, even if it's declared a total loss. So, in theory, you can be a total capitalist and "waste money."
My point was not to assume that this makes sense economically just because Apple did it. They have other ways of getting their money back and if they lose, it's just a rounding error http://finance.yahoo.com/q/cf?s=AAPL&annual