Tie office overhead lights to your CAC card, similar to many hotels with their room keys. This way the lights would be on only when needed. Built in (DO NOT RETROFIT - TOO COSTLY) into new buildings programable light pads i.e. lights come on 0700 off 1700, after those hours you need to program time in 1 hr blocks manually for those who leave after hours. At least lights would not be on 24 hrs a day.
Computers,monitors, printers, and other office device use electricity when on standby. Often it is as much as they use when on, one way to save energy is to completely shut down all items completely. Another idea would to attack all items to a power strip and flip the switch when not in use or at night.