MCT Lecturer in Technology Management Malcolm Fowles provides advice on how to save energy in your work and home offices...
Portable versus desk computer
Using data shared by my students on T152 Energy measurements at home, we found that our laptops used on average about a third of the power of our desktop computers. If these are typical, and work an eight hour day, the difference between them is about £25 per machine per year at domestic electricity prices. Another difference, of course, is at least a third of the damage to the environment.
If you have the choice, use portable.
Screen savers
Your screen doesn’t need saving! Very few of us now use an old-style monitor that engraves a static image on the tube, but many of us still run a screen saver. Far from saving anything, most screen savers actually use more energy than ordinary office software. Our worst offenders tended to be those that render 3D objects, and those that cycle round photographs.
Attached devices
Any device connected to your computer may be using energy, even if you think it is switched off. Trust nothing. For example, my USB memory stick adds a constant 20 per cent to my laptop’s energy usage when plugged in. A laser printer on standby may be drawing as much power as a low-energy notebook computer. Even a power cable with no machine attached may be using energy if it is in a socket that is switched on!
Powering down
A typical computer left idle uses very nearly (more than 98 per cent) as much power as one being used continuously for normal office tasks due to the way the processor works.
Why do we leave our computers on? It appears that the main reason is the time it takes to restart after switching off. The longest reported delay, from start-up switch to password prompt, was five minutes. The average was 97 seconds – more than a minute and a half. That kind of delay is not acceptable to most people during the working day or when at home.
There are, however, alternatives to powering down your machine if the start-up time is an issue. Almost all computers have power-saving options, primarily these are that the processor stays on but the screen (monitor) is powered down; the processor is powered down after all contents are saved to memory for a quick restart, often called Standby or sometimes sleep mode; the processor is powered down after all contents are saved to disk for a fairly quick restart, often called hibernate or sometimes (confusingly) sleep mode. All of these alternatives have much quicker restart times than a shutdown.
Taking it further
- The Carbon Trust has developed a fact sheet with tips and guidance on saving energy in the office
- To find out more about all things environmental, go to the OU’s OpenLearn website which has brought together educational resources on the topic