Sleep Mode

What have power saving technology achieved and where is it heading in the future

Sleep mode is a low power mode for electronic devices such as computers and is used when a device is idle. Sleep mode saves electricity as less power is required during sleep mode than in normal operations. This is commonly archived in laptops by turning the screen off after a period of inactivity and in desktop PC's monitors will turn off after a period of time. More recently more advanced power management as been introduced including the ability to turn of hard drives and to save the RAM to hard disk (Hibernation).

The latest Macs from Apple can now have a shut-down and wakeup time pre-set. This would be great in all computers and would be especially useful in offices where equipment is turned off overnight it would stop people forgetting to turn their computers off and could be used on servers in offices that could be shut down 1 hour later than the rest of the office to allow any remaining data to be processed and woken up an hour before the rest of the office so that the network is already to go like it was never turned off. One main reason that servers in particular are not turned off is because they take a long time to reboot and re-establish all the connections needed. This has potential for home users as well. One excuse for not turning their computer off often is "I want it all loaded and ready to go when I want it" this is something that I have said and done myself until finding better options such as automatic hibernation and setting a wakeup time on my new Mac book.

Other possible reasons for using sleep mode or hibernation include reducing wear and tear on certain components such as processors, or reducing noise levels in the working environment as fans will not need to be running and air conditioning would not be needed to extract the heat from the room as is found in many offices. Air conditioning and refrigeration are two of the biggest consumers of electricity in the world

But energy saving is the usual reason for using sleep mode. When I think how many PCs are running at any one time around the world, millions of them and each consuming over 300 watts of power or more, power supply units just keep getting bigger to cope with the new generation of hardware, multi core processors and high specification graphics cards all consume a lot of electricity and a lot of this power isn't used productively. If everyone used sleep mode and hibernation the amount of energy that could be saved is huge and could have a significant impact on the rate of climate change as less power needed would result in less fossil fuel having to be burnt.

Power saving has penetrated the portable computer market to saturation with current technology. The only possible development in this market is the move to solid state hard drives using flash memory which use less power [1]

The technology does exist in the desktop PC sector put has not been utilised to its full potential and a survey I conducted suggests consumers lack information about how much power saving technology is in desktop PCs. One of the questions I asked was:

What Power Saving Methods do you use on your Desktop PC?

I didn't give any multiple choices on purpose as I wanted to see what people actually used.
10 of the 20 people I asked said Screen savers as the only power saving method they used.

Screen savers are not power management features, In fact, screen savers can actually waste power, because they can prevent the computer from entering low power modes and they often cause the CPU to perform more calculations, and keep the hard disk running for longer than if the computer were idle. Screen savers are nothing to do with power saving whatsoever and are somewhat irrelevant with modern screens with the only purpose being security and entertainment. [2]

More advanced power saving technology is being developed all the time and over the coming years will be common place in most electronic devices as not only are consumers wanting it so they can be more environmentally friendly and save on ever increasing fuel bills. Standby on electronic devices is responsible for 8% of all domestic energy use and the British government is trying to ban standby in new devices. Not many devices consume a lot of power in standby mode but when you consider how many of these devices there are in the average home let alone across the entire country.

“A significant proportion of the population leave their mobile phone charger plugged in and wasting energy all of the time whilst believing it to be inactive. Although the stand-by power consumption of a single mobile phone charger only averages 1 watt, the combined stand-by usage of approximately 25 million of these items adds up very quickly to 25 megawatts. This adds up to 219 GWh consumed per annum, enough energy to power the electricity needs of 66,000 homes for one year.” [3]

As can be seen from the energy review by the DTI, The amount of power that can be saved in staggering.

A report by the University of Miami estimates that an average PC is in use 4 hours each work day and idle for another 5.5 hours. The same report also suggests that 30 - 40% of Office PC's are left running overnight and at weekends when the office is closed.[4]

A PC is sleep mode consumes around half of the amount a PC running at 100% does. But the only way to really save energy and improve the life span of components is to shut down completely. A Monitor consumes nearly as much power as the rest of the computer put together which again shows why using screen savers does not save any energy. CRT monitors use up to 80 watts of power when in use and this will drop by up to 90% so this is great when leaving your PC for a few hours.[4] The only disadvantage to doing this with CRT monitors is they can take a while to come out of low power mode. LCD screens on the other hand are much more power efficient consuming less than 30 watts when running and as little as 3 watts when in a sleep mode which is equivalent of 3 mobile phone chargers not in use which is about as efficient they will ever get. Reducing the amount of energy used by PC's also reduces secondary uses of energy namely air conditioning as computers generate a lot of heat. There are now ways to activate sleep features across entire networks of computers saving time. A lot of these solutions are open source.[5]

There have been many attempts by the governments of the world to reduce the environmental impacts of information and communication technology. The European Union has put in strict regulations about its disposal at the end of its useful life as computers contain a lot of toxic and dangerous chemicals it is called the Waste Electrical and Electronic Equipment (WEEE). [6] The latest attempt the British Government has the possibility of making the most impact in electronic design and power saving ever by getting rid of a feature that is not a vital part of the electronic system and a work around using less or no energy will be found so that consumers have the same convenience as standby safe in the knowledge that they are not contributing unnecessarily to climate change.

References

[1]Solid State Disk - Wikipedia, the free encyclopaedia (No Date) retrieved on 15/01/08, http://en.wikipedia.org/wiki/Solid_state_disk
[2]Screensaver - Wikipedia, the free encyclopaedia (No Date) retrieved on 15/01/08,http://en.wikipedia.org/wiki/Screensaver
[3]UK Government to ban 'Standby' Buttons! 28/072006 retrieved on 15/01/08, http://forum.tabletpcreview.com/showthread.php?t=2592
[4]Computer Power Management - Information Technology - University of Miami Leonard M. Miller School of Medicine (No Date)
retrieved on 15/01/08, http://it.med.miami.edu/x1159.xml
[5]Save $25 to $75 annually per computer with power management features - Energy Star (No Date)
retrieved on 15/01/08, http://www.energystar.gov/index.cfm?c=power_mgt.pr_power_management
[6]EC Directive on Waste Electrical and Electronic Equipment (WEEE) - BERR (No Date)
retrieved on 15/01/08, http://www.dti.gov.uk/innovation/sustainability/weee/page30269.html