We all know LEDs are low voltage light sources. To power them using today's traditional infrastructure requires AC power from the wall that must be converted to low voltage DC power in a driver that is inside each light fixture. Adding this driver not only adds cost, but creates a potential point of failure and add a source of heat to the fixture.   University researchers at Carnegie Mellon published a report in Energy Policy indicating the cost advantages of DC to LED vs. AC to LED. Redwood's approach to lighting controls uses this approach. AC power is converted to DC in a centralized driver (Redwood Engine) and then carried to the fixture using low voltage cable. Power, communication and control are all carried over a single low votlage cable. Link to the article at http://www.ledsmagazine.com/news/9/4/28