ES: Engineered Systems, Jan. 2, 2014, by Michael R. Olson.
http://www.esmagazine.com/articles/96322-vfd-serial-communications-which-points-should-i-use-and-why

"The available LEED credits and most obvious energy-saving possibilities are one thing. The potential for a ripple effect of system-wide savings by deploying VFDs [Variable Frequency Drives] as part of better overall monitoring are another."