Personal computers (PCs) are one of the fastest growing electricity loads in business and academic arenas. According to one recent estimate there are about 26,800 PCs and nearly half that number of printers currently used in University of Michigan (U-M) buildings. Although it is difficult to estimate, PC operation probably accounts for over 10 percent of all electricity used by the U-M.

The U-M Utilities and Maintenance Services Department, Energy Management Division, has written and distributed a booklet titled UM Guide to Green Computing: What You Can Do To Conserve Energy On and Off Campus. This information guide highlights some of the advice contained in that booklet.


Applicable Regulations


Overview of Procedure
The increase in U-M consumption of electricity and paper causes an increase in air pollution, solid waste, and the burning of fossil fuels. Much of the paper used by PCs is wasted. National estimates indicate that most PCs are not being used most of the time they are on. In addition, 30 - 40 percent of all PCs are left on overnight and on weekends.

On the U-M Ann Arbor campus, PC operation alone may account for at least $1.8 million in energy costs each year. This represents approximately 11 percent of the total amount spent by the U-M on electricity. It is estimated that a PC system can easily consume 300 watts of electricity per hour the same amount of energy needed to operate three 100 watt light bulbs.

The following "green computing" habits can significantly reduce the amount of electricity and environmental waste for which PCs are responsible.


Waste Minimization Procedure
Electrical Conservation Tips:

  • Turn the computer off overnight and on weekends;
  • Wait until ready to use the PC before turning it on;
  • If the computer is going to be inactive for more than 16 minutes, consider turning it off. After this time, the energy needed to run the computer outweighs the start-up energy;
  • Do not turn on the printer until ready to print, even an idle printer consumes energy;
  • Try to schedule computer-related activities to do them all at once, keeping the computer off at other times;
  • If spending a large amount of time at the computer, consider reducing the light level in your office. This may improve cathode ray tube screen visibility as well as save energy.

Paper Conservation Tips:

  • Use "paperless" methods of communication such as electronic mail (e-mail) and fax modems. Also, do not print out copies of e-mail messages unless necessary;
  • Use smaller font sizes and decrease the spacing between lines, or reformat to keep the document to as few pages as possible;
  • Review documents on the screen instead of printing a draft. If you must print a draft, use the blank back side of used sheets;
  • Use a printer that can print double-sided documents. When making copies, use double-sided copying;
  • The U-M buys and uses recycled-content paper when possible. Look for papers with 50 - 100 percent post-consumer waste and non-chlorine bleached. Also, recycle paper when done.
  • Store information on diskettes rather than in "hard copy" format. A single high-density 3.5 inch floppy disk can hold the equivalent of 750 sheets of paper, about one and a half reams. Also, be sure to reuse disks that contain outdated information.

Purchasing and Use of Equipment:

  • Printer toner cartridges can be refilled, rebuilt and reused. Many manufacturers will take a spent cartridge, refurbish it, refill it, and return it for about half the price of buying a new one;
  • Determine whether you can upgrade your existing equipment rather than purchasing new equipment;
  • Donate an old computer to a school or charity; if it is permanently out of order, give it to a computer recycling facility instead of discarding in a landfill;
  • Only buy a monitor as large as you really need; a 17 inch monitor uses 40 percent more energy than a 14-inch monitor. Also, the higher the resolution, the more energy it needs;
  • Consider purchasing an ink jet printer instead of a laser printer. Although they are a little slower, they use 80-90 percent less energy;
  • Request recycled or recyclable packaging from your vendor;
  • Buy soy or non-petroleum based inks. These printer inks are made from renewable resources, require fewer hazardous solvents, which translates to fewer air emissions, and in many cases produce brighter, cleaner colors;
  • Try to buy energy efficient products such as those bearing the Energy Star Logo. The Energy Star Program was started by the Environmental Protection Agency (EPA) to encourage the production and use of energy-efficient equipment. In accordance with the EPA's voluntary guidelines, leading computer manufacturers are now producing equipment that can automatically power down to a "sleep mode" to save energy when not in use. They also use up to 30 percent less energy when running than conventional equipment. These added capabilities do not increase price or decrease performance.


Known Limitations
None known.


Safety & Health Precautions/Personal Protective Equipment
Not applicable.


The production of electricity is the largest single source of air pollution, due to the burning of fossil fuels. A power plant used to generate electricity, burns oil, coal, or natural gas that emits gases such as carbon dioxide, sulfur dioxide and nitrogen oxides. These gases, in turn, cause acid rain, smog and global warming. Conserving energy reduces the amount of fuel that has to be consumed, thereby reducing the amount of pollution generated. Obviously, energy-efficiency is a positive step toward reducing air pollution.

Some of the tips given above to reduce paper use and reuse of toner cartridge and diskettes will go a long way towards reducing the amount of solid waste that ultimately ends up in a landfill.


None known.


Project Related Costs
Information not available.