This saves $201Mill/yr. I propose a "Smart Upgrade Program" that shuts down computers completely when not in use. The automated shut-down would happen 6 days/wk (to allow one night/wk for system upgrades/updates/scans), and only if no users are logged into the computer (i.e. not actively in use). A macro or systems software could be developed (maybe even for free by Computer Science majors at one of the service academies), and then the program could be mandated on all Fed CPUs.
The major issue always comes from the IT community. They say that upgrades/updates/scans must be done during the "after hours" time to reduce the inconvenience to workers. Standard practice at most gov offices is to never shut it down. This policy is blatant waste in the name of convenience.
An average CPU in "standby" mode (computer is logged off, monitor blank, but computer is not fully "shut down") uses 1.01 KWH of electricity during non-duty hours. At 16cents/KWH, this is 16.16cents/day of electricity, and 25.85cents/day on weekends. Annually, this is $60.50/CPU/yr (counting 6 days/wk to allow the one day left on for upgrades).
If 3/4 of the Fed employees have "their own" computer at work, in 2009 numbers), there are 3.3 million computers (3323250 to be exact, but many have multiple computers and some personnel have none). At $60.50/computer/yr, the cost savings in electricity bills would roughly be $201 Million.
The day for upgrades could even be chosen by the IT personnel so the program does not create a security risk.
This program would decrease the fed gov's carbon footprint, and would help meet the goals of EO 13423 and 13514 (directing the fed gov to reduce consumption).
Note: I collected energy information by plugging in a "Kill-a-Watt" meter into my existing computer, at my work, for 15 hrs overnight. I used the Fed Gov population numbers from an online report of 2009 Fed Gov statistics. Energy costs vary in different locations, some less than 16cents/KWH, and some more.