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Power Consumption and Energy Saving Potential of Devices

 © 2009-2014
Christian Bachmann

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Surveys carried out in western countries have all come to the conclusion that office electronics belong to the electrical loads with the highest growth rate. In the USA it is estimated that presently these power requirements amount to 6 GW (the equivalent of 6 large baseload generating stations); if growth remained at this, it would result in up to a quadrupling within ten years [4]. With the present state of technology, power consumption by office electronics alone would increase in the European Community to 10 GW in the mid-nineties [12]. In Switzerland office electronics accounts for more than 5 percent of the power used in the service sector [11]. Another Swiss study based on measurements of the power requirements of equipment revealed that the devices with the highest consumption (fax, printer, copier) use between 50 and 80 percent of the energy when they are in the stand-by mode [6]. This may apply to other countries as well.

In Switzerland energy consumption figures for office and consumer electronics equipment are at about the same level. In both, stand-by losses make up between 3 and 4 percent of electricity consumption in the household and service sectors [11].

Table, showing the share of stand-by losses of office and consumer electronics in Switzerland.

It is very difficult to make any meaningful statement on the potential for energy savings of devices since technology is in rapid development and present predictions may already be outdated tomorrow. With the technology to be found on the market in 1993 energy consumption could be decreased by about 30 to 80 percent. Based on technological developments it can be expected that computers and monitors will have the same level of performance, and use only a few percent of the present power consumption. The biggest saving is to be expected in the stand-by mode; according to a Swiss survey depending on the type of equipment between 30 and 60 percent of the present energy consumption of the devices tested [11].

The Swedish Board for Industrial and Technical Development (NUTEK) proposed one watt as a target value to be aimed for in an energy saving mode after one hour. The device should automatically set to this value after one hour of non-utilization [9]. The feasibility was discussed at the Zurich meeting. The participants agreed that these target values may prove realistic for certain groups of devices (computers, monitors). For technological reasons stand-by losses cannot now be reduced to one watt in output devices (printers, copiers). With technology being in a constant state of flux this may change in the near future. It was also pointed out that a sheet of paper of the size A4 or US-letter contains 20 Wh of energy, roughly ten times more than is needed to print or copy onto this same page of paper. The most important saving measure therefore consists in imprinting both sides of the paper [3].

© Christian Bachmann