This page is under construction!

A single desktop computer will consume approximately £75 of electricity per year if it is left on all the time. If a computer is put into a low power state when it is not being used this cost is likely to fall to £15 per year.This figure extrapolated to the estimated 720 000 computers in UK Universities equates to an annual saving of around £40 million. The assumptions in these headline figures will not match every organisation so it is advisable to gather information about usage patterns, computer power consumption and electricity tariffs and plug them into one of the [http://wiki.oucs.ox.ac.uk/ltg-public/lcict:predict_and_plan prediction models] descried in this wiki.

Switching computers into low power states when they are not doing useful work is more problematic than turning off a light bulb or television. People familiar with the way institutional computers are used and managed will recognise at least some of the following scenarios:

This section of the Low Carbon ICT wiki aims to describe a range of tools and practices that can be adopted by ICT managers and users to reduce the amount of energy that is wasted through the use of desktop computing infrastructures.

TableOfContents([2])

Tools and practices

Waking computers remotely

It is possible to provide the ability for IT managers and end-users to wake specific computers remotely. By providing such a facility it becomes possible to switch computers into low power states more often. For instance, many organisations will ask their staff to leave their computers on so that the a backup service can access the hard drive and create a central copy. If computers can be woken up by the backup service then users can switch their machines off without disrupting this essential activity.

(Insert a good description of WoL).

If implemented successfully this approach can be used to achieve significant energy savings because users can be asked to switch their machines off at the end of each working day without effecting software update or backup schedules. The WoL service can also be used by people who need to turn their computer on when they are away from the office. Indeed such a service can be used to reduce the workload that results from computers that missed software updates and backups because they had been switched off.

Unfortunately the development effort to provide a WoL infrastructure is not small and may not be appropriate for organisations that have computers distributed across a large number of subnets.

Case study: University of Oxford's WoL infrastructure

[http://wiki.oucs.ox.ac.uk/ltg-public/lcict:wol_oxford_university The University of Oxford wake-on-LAN infrastructure] enables IT officers, end-users and managers of 3rd-party services to wake computers remotely.

Configuring computers to move into low power states automatically

Most computing devices are built to be able to detect when they are not being used. Desktop computers have four main power states: On (S0) Sleep or standby (S3) Hibernate (S4) Off (S5).

(Insert form for submitting meter readings)

Form design: Capture: manufacturer, operating system, name of data gatherer, organisation, power consumption at different states, power consumption while doing range of activities, manufacturer of meter, age of computer

provide links to graphics that show restrict access to full data to people that have submitted readings.Computers can be moved between these states manually by individuals, automatically by software installed on the computer after a pre-configured amount of time, and remotely by using a wake-on-LAN service or a service that allows a machine to be switched off remotely. It needs to be stated at the outset that many ICT managers have tried to implement automatic power management but found that:

  1. Computers are put into low power states when important processes are running
  2. Computers fail to go into low power states when they should
  3. Computers behave unreliably after they are woken from a low power state

At this stage these observations are unspecific and need further detail. If ICT managers are to feel confident that they can use the in-built power management facilities advertised by most operating system vendors then we need to better understand what causes these issues arise, and whether there are any solutions. We will collate these issues and solutions in the

Switching computers off automatically

Case study: Switching computers off automatically at Liverpool University

Configuring standby (S3) and/ or hibernate (S4)

Case study: Configuring computers to move into standby automatically at Liverpool University

Asking users to switch their computers off

Case study: Asking users to switch their computers off at the University of Oxford Case study: Asking users to switch their computers off at the University of Leeds

Disable screen savers

Only switch computers in clusters on as needed

Life-cycle considerations

The manufacture and transport of computing equipment results in a considerable amount of CO2 to be released into the atmosphere, many of the components are considered toxic waste and have to be carefully recycled, and the manufacture of circuit components requires large volumes of clean water. With this in mind it becomes obvious that for any organisation to truly improve its environmental performance it will have to carefully control its procurement processes.

Extend the life-cycle

Buy equipment that will perform useful work for the longest period of time. Notes: warranty, system maintenance to improve performance.

Promote greater sharing of resources

Organisations can reduce their carbon footprint by buying fewer devices and asking people to share equipment more often.