As I have been told, in 2020, all new houses in California are to be Net Zero Energy. While we have made progress in recent years, it seems a tall order. Yet if we design houses utilizing the Passive House Standard it is very doable. In fact it is being done.
Check out "Passive Passion" by Charlie Hoxie, http://www.foursevenfive.com/index.php?main_page=page&id=30&chapter=1.