The roof will essentially have solar panels, and nothing else. The reason is simple, and that is to provide for some of the electricity this building will demand. In the unlikely event that the panels produce more than is consumed, those benefits will go to the other buildings such as electricity credits for the Tower which will not be able to generate enough electricity for a 31 story building. As with all roofs, they will be converted into flat roofs so the solar panels can be sun tracking panels generating an extra 50% electricity.