The energy consumption of desktop computers: measurement and savings potential

The energy consumption of desktop personal computers was studied at three Canadian Federal Government sites, and the potential for energy savings through power management investigated. The power draw of computers and their peripherals was measured using a portable meter, and use profiles were recorded using custom software. The measured plug loads were considerably lower than nameplate ratings. Use profiles from 94 computers indicated that there were long periods during both night and day when the computers were turned on but not being used, and it was predicted that significant energy savings could be achieved if electricity consumption was more closely tailored to actual usage. Two methods of realizing these savings were tested in the field. Stickers reminding users to switch off computers when they were not being used produced reductions in mean computer energy consumption of 14% over an eight week period. However, these savings diminished with time. An automatic power management system designed to switch off computers and peripherals after a user-specified period of inactivity produced reductions in mean computer energy consumption of 63%, while visual display unit mean energy consumption was reduced by 82%. These savings were maintained over an eight week period