If Apple is really convinced of the "greenness" of their data center they should call Greenpeace out and ask them if they can point to another data center that is "greener" per unit of capacity (or whatever measurement they use). If they can't, then they will have, in effect, gotten Greenpeace to say that they have the "greenest" data center on Earth.
However, I doubt that Greenpeace would answer such a query.
However, I doubt that Greenpeace would answer such a query.