There are a variety of different uses for computers at the University and at home. Information on energy efficient options for these different requirements is detailed on the links below.
When operating a computer the only condition in which no power is consumed is when it is switched off.
Quick energy savings can be acheived by switching monitors off at lunch times and when out to meetings, as there is no waiting for the equipment to re-start. Further these can be switched off overnight and at weekends.
For Base Units:
These can be switched off at the computer, and at the plug, overnight and at weekends
Screen savers are not primarily designed to save energy, but to maintain the screen, and while some do reduces energy consumption by a small amount it is much better to ensure that the power saving settings are set up on the computer as detailed below.
Computers have energy saving features that can be set up to automatically reduce power levels after pre-set time periods when the machine is not in use. For users that do not have managed desk tops on their machines the “Power Management” options need to be checked to see that they are set up correctly. To access “Power Management” go to “Control Panel” and open the “Power Management” feature. In Power Management use the “Power Scheme” to select Home/Office Desk and adjust settings to:
Turn off Monitor
Turn Off Hard Disks
After 30 mins
Average time settings are indicated and these can be adjusted, based on personal use, to shorter times.
Active State (Normal operation)
Idle State (Normal Operation)
Sleep Mode (Setting that computer is switched to by Verdiem)
Switched off at the computer
Switched off at the mains
Hibernate (Alternative mode of operation)
Active State (Normal operation):
The state in which the computer is carrying out useful work in response to a) prior or concurrent user input or b) prior or concurrent instruction over the network. This state includes active processing, seeking data from storage, memory or cache, including idle state time while awaiting further user input and before entering low power modes.
≤ 175 Watts Category B desktop Energy Star 5 rating
72-120 Watts University PCs
Idle State (Normal Operation):
The state in which the operating system and other software have completed loading, a user profile has been created, the machine is not asleep, and activity is limited to those basic applications that the system starts by default.
≤ 65 Watts Category B desktop Energy Star 4 rating
64 Watts University PCs
Sleep Mode (Setting that computer is switched to by Verdiem):
This is a low powers state that the computer is capable of entering automatically after a period of inactivity or by manual selection. A computer with sleep capability can quickly ‘wake’ (=<5 seconds) in response to network connections or mouse click for example.
≤ 4 Watts Category B desktop Energy Star 4 rating
3-8 Watts University PCs with active Verdiem power management system
In Standby your computer uses less power than when it’s just sitting on your desk not being used. It stays available for immediate use; an activity can trigger return to normal operation mode. The information in memory is not saved on your hard disk. If the power gets interrupted, the information in memory is gone.
This mode is fully pre-set on all desktops, notebooks, and workstations manufactured after July 20, 2007 that display the ENERGY STAR 4.0
≤ 4 Watts Category B desktop Energy Star 4 rating
3-8 Watts University PCs
Switched off at the computer:
A computer switched off using the power button, but not switched off at the mains will continue to consume power.
≤ 2 Watts Category B desktop Energy Star 4 rating
2 Watts University PCs
Switched off at the mains:
Your computer uses zero energy when "off." That's true only if it is unplugged.
The computer need to be manually switched on.
Alternative mode of operation (not recommended)
It’s just another power-saving state. In Windows Vista, sleep saves your settings in memory and draws a small amount of power to maintain that memory.
Waking from a state of hibernation takes longer than waking from sleep. This is because your computer needs to load your data and applications from the hard drive back into memory. This process may cause problems with the computer drive or software during the re-launch.
Hibernate mode is useful on laptops when you know you won't be using your computer for an extended period of time and you won't have an opportunity to charge the battery.
2-3 Watts typical range for computers
There are approximately 1,500 classroom p.c.'s at the University. Historically these machines were left switched on overnight to allow updates to be installed resulting in a large amount of energy being wasted.
The University's Directorate of Information Technology (DIT) took the decision in 2008/09 to investigate the installation of software that would allow these computers to be remotely switched off, and on. The benefits being that it would be possible to power down the computers when they are not in use, and when it was necessary to install updates the computers could be powered up just for the duration of the updates.
The decision was taken to proceed and the software was installed in 2009. In addition to powering the computers down overnight and at weekends the system powers the computers down after half an hours inactivity during the day achieving additional savings. It is projected that for the class rooms the system saves ~410,000kwh p.a. equivalent to reducing carbon emissions by 222 tonnes p.a.
There are approximately 4,500 office p.c.'s at the University. These machines are typically switched on and off by the users. This can result in computers being left on overnight and at week ends. In addition when people attend meetings or site visits, computers are typically left on becuse of the time it takes to re-start the machine if it is turned off.
DIT has installed software that allows computers to be remotely turned off and on remotely. This software means that if computers are left on unintentionally overnight and at week ends then they will be automatically powered down. At the same time if it is necessary to install updates overnight then the computers could be powered up just for the duration of the updates. For day time operation the computers are set up to powerdown after half an hours inactivity. The re-start time from this energy saving mode is just a few seconds. This system is being rolled out to sections of the University as it is requested. By having this sofware installed it is possible to reduce your computers energy consumption by up to 66%. If you would like to register to have your machine set up with remote switching please contact John Kingsland.
This page was last updated on 13-Aug-2010 14:16:02 BST