I am not a fan of the government (city, state, or federal) mandating where or how we spend our money. With that said, I agree that all new construction should install solar panels. And this is just what San Francisco, CA has just mandated with their latest legislation.
The specifics state that new buildings 10-stories tall or less will have to install photovoltaic solar panels or solar water heaters. This law goes into effect January 1st, 2017.