Green Team
Computer Energy Savings

By: Ken Woolfe, November 2000

Computer and office equipment energy use is a rapidly increasing segment of energy use in the U.S., and the Federal Government is one of the largest users of office equipment. The problem of increasing energy use and waste is not going away. Energy alerts and shortages may become routine unless we take action. Here is some information to help save energy, extend equipment life, and save money in a simple and responsible manner. Use these procedures at home, also.

Common myths -
1) Won't powering my computer on and off hurt it?

Answer - No. This was true on early computer equipment but not on current equipment.
2) I already use my screensaver, doesn't it save energy?
Answer - No. Screen savers do NOT reduce monitor energy use significantly.
3) Does MY small energy use really matter in the big picture?
Answer - Yes.

What's at stake -
In the aggregate the stakes aren't trivial. With millions of pieces of office equipment in the U.S., a significant amount of energy is wasted when equipment is on without being used. The use of power management features now saves 23 terawatt-hours a year, a Berkeley Lab energy analysis group estimates - roughly a quarter of what this equipment would otherwise consume. This is equal to the continuous output of 5 good-sized (500MW) power plants. With "complete saturation of power management" -- if such capabilities were built into all equipment and activated - an additional 17 terawatt-hours a year could be saved (3 more power plants). (Note:a terawatt = a trillion watts: 1,000,000,000,000). Remember these savings are without any loss of function or productivity. Power management saves what would otherwise be "pure waste."

What you can do -

Three options for saving energy in office equipment, in order of simplicity and effectiveness, are:

1. Set your power management features and customize them for your needs. Newer equipment has built-in energy management technology, including low-power "sleep" modes. Enable them in the user control panel. (Note: Windows NT does not have this feature. However, it can be set from the computer's BIOS setup. See the computer user manual or call your computer help desk). Here are some guidelines. Set the monitor to go to sleep after 1/2 hour without use and the entire system to go into sleep mode after 1/2-1 hours. For system stability, first make sure monitor sleep-mode is enabled and working fine (it saves the most energy), then try for the processor/hard-disk power management features. If the processor power management causes problems with network access, etc., disable it.

2. Power down the entire computer system (printers and other equipment, too) at night and on weekends: This option will save energy and extend the life of your computer. It is a common myth that turning computer equipment off and on is bad for it. Research on current technology shows an improvement in system life when the equipment is turned off, since heat and mechanical stress are the two leading causes of computer failure. On older equipment (10 years ago) there was concern about power cycling stress, particularly on hard disks, but this is not true on newer equipment. Equipment will become obsolete long before failure due to power cycling. Your equipment will also be less vulnerable to damaging voltage spikes cause by weather or power failures.

If your computer has automated back-ups, no energy management features or there are other reasons to leave your computer on you can still….

3. Turn off the monitor at night and on weekends: Monitors use 1/2 to 2/3 of the computer system's energy requirements (about 70-120 watts for the average monitor). If you are really conscientious, you can turn off your monitor anytime you will be away from your desk for at least 1 hour.

In addition, Turn off other equipment - Don't forget to turn off heat/air conditioning, fans, lights (if not on an automated sensor) and other unused equipment. Anything that generates heat/cooling takes significant energy.

For more information go to:
Energy Star
CIS Knowledge Base

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Last updated 3/13/06