All offices are full of computers, but they are kept on to "push patches" at night. They don't sleep since they'd ignore the network commands to wake up, so they stay in a ready state all night drawing approx 80 watts per PC (the monitors sleep, but not the PC itself) yet the patching process only takes a few minutes. We effectively have an incandesent light on for every desk in every room in every building in the DOD. If we'd shut down PCs at night, then just give them 20 minutes to run patches in the mornings, we'd save millions in electricity.
Idea No. 4837