In 2015, about 40% of total U.S. energy consumption was in residential and commercial buildings -- about 39 quadrillion BTUs. Unfortunately, much of it was wasted: Homeowners left air conditioning on in empty homes, office workers kept equipment and lights on overnight, etc. Clearly, making buildings smarter in terms of energy usage would save money and lower environmental impact. In their paper, "Smart power opens door to more efficient electrical use," Ajinder Singh and Kripa Venkat explore five key technologies to enable smart buildings