'Big data' is solving the problem of $200 billion of wasted energy

At its best, technology is able to tackle huge problems with remarkable ease. The General Services Administration, for example, has found a way to save $13 million a year in energy costs across 180 buildings -- all thanks to a proprietary algorithm developed and monitored from many states away, in Massachusetts. Among the problems discovered: malfunctioning exhaust fans. And Kohl's department store has installed energy-efficiency software in 1200 stores nationwide. "We look at the energy meter a...