Let's start with the premise that according to the U.S. Department of Energy, commercial buildings account for 35% of US (and 40% of Global) electricity consumption.  Then, add on a regulatory structure in which the President is calling for a 20% reduction in energy consumption and a state (California for example) challenging (or possibly mandating) that all new commercial buildings be "zero net energy" by 2030 as a means to curb the adverse impacts of climate change. Finally, (and assuming I have not lost everyone), take a deep breath and consider the relatively benign question of how do we possibly get there?