Header Logo
Home   Hardware   Software   Storage   Networks   Internet   Mobile   Web 2.0   Cloud   Big Data   Green   Quantum   Security   DSE Regs   HOT!
Green Computing


Computing is not currently very environmentally friendly. Indeed, in the May 2010 edition of the Greenpeace Guide to Greener Electronics only 2 out of 18 of the PC and other electronics manufacturers listed obtained a reasonably green rating. The two companies concerned were Nokia (1st) and Sony Ericsson (2nd).

Things, however, are starting to change. For a start, businesses are increasingly keen to make energy and hence cost savings in the face of rising electricity prices. The strength of public and corporate opinion shifting in favour of environmental responsibility is also growing rapidly now that climate change is a political and regulatory reality. Computing is also an area of human activity in which there are real environmental savings to be made, some of which can be achieved by implementing relatively straight-forward practical measures with existing hardware. There are now even pieces of software -- such as LittleGreenGenie -- that permit companies or individuals to measure, reduce and carbon offset the emissions resulting from their computer use.

The following section provides an overview of the current state-of-play of green computing. You may also find helpful my related videos Explaining Green Computing, Shut Down and Switch Off and Building a Green PC.

Just one other particularly strong source of information on green computing is the website GreenerComputing.com.


According to a report from the United Nations University, it takes about 1.8 tons of chemicals, fossil fuels and water to produce a typical desktop computer -- and world-wide over one billion PCs have been sold. A December 2006 Computer Weekly article on green computing also reported a Carbon Trust estimate that office equipment currently accounts for around 15 per cent of total UK energy use. This figure is expected to rise to about 30 per cent by 2020, with computer equipment to account for about two-thirds of this energy consumption. In April 2007, a Gartner Press Release also estimated that the global information and communications technology (ICT) industry accounts for about 2 per cent of global carbon dioxide emissions, or roughly the same as aviation.

Personal computer power use is ripe for making environmental savings. The Climate Savers Computing Initiative estimates that the average desktop PC wastes over half of the power delivered to it. Estimates from other sources concur. Intel, for example, estimate that a typical business desktop could reap a 60 per cent energy saving by implementing what they term "aggressive power management".

Key to all of these energy saving opportunities are reducing the power used by a computer when doing nothing or very little. Computers should, for example, not be left on overnight or over the weekend. Whilst this may seem "obvious" good practice, in 2006 the National Energy Foundation estimated that in the United Kingdom around 18 per cent of computers are never turned off, resulting in 1.5bn kWh of power being wasted and 700,000 tonnes of carbon dioxide being emitted due to workers simply not shutting down their PCs. A similar study in the United States in 2007 even more starkly reported up to 60 per cent of office PCs being left on overnight, resulting in 19.82bn kWh of electricity wastage and 14.4 million tonnes of associated carbon dioxide emissions.

Measures such as turning off idle PCs -- or even just turning off screens when not in use (rather than running an energy-consuming screen saver) -- are simple but highly effective. Trewin Restorick, Director of environmental charity Global Action Plan that helps companies to make energy savings, even suggests that companies should find "non-intimidating ways" of naming and shaming staff who leave monitors on, such as tying balloons to their desks.


To try and promote the above and other opportunities for more environmentally-friendly computing, in 2007 the Climate Savers Computing Initiative was set up by Google, Intel and a number of other leading players in the computing industry. The Initiative set itself a target to increase the energy efficiency of all computers shipped in 2010 by 50 per cent. This was hoped would reduce global carbon dioxide emissions from the operation of computers by 54 million tons per year, equivalent to the output of 11 million cars, or 10-20 coal fired power stations. Total energy savings would then be equivalent to 62 billion kWh and worth over $5.5bn.

The Climate Savers Computing Initiative has yet to specifically report on its initial targets. However, by July 27th 2010, a study conducted by Natural Logic showed that the IT sector had reduced annual CO2 emissions associated with IT equipment by more than 32 million metric tons worldwide since 2007. The research also showed that the IT sector was on target to achieve the intial Climate Savers Computing Initiative’s hoped for environmental savings by the end of its 2010 fiscal year in June 2011. Looking ahead, the Initiative is intending to leverage the expertise of new members -- including Cisco, Emerson Network Power and Juniper Networks -- in an attempt to reduce the power consumption of always-on computer hardware devices such as network routers.


Whilst putting a computer into a "standby" or "sleep" mode will save a lot of power, many people remain unaware that even shutting down a desktop computer completely does not turn it off. This is because the computer's power supply will remain physically switched on, with the motherboard partially powered and waiting for a signal from the switch on the front of the PC (which is not a mains power switch) to boot up again. To actually prevent a desktop computer from using power, after being shut down it must either be switched off at the wall socket, or turned off using the small rocker switch on the back of the power supply.

As shown in the Explaining Computers video Shut Down and Switch Off, a typical desktop computer uses about 8W of electricity an hour when shut down but not switched off. That's about 1KW of electricity being wasted a week for a PC turned off around 16 hours a day. It therefore really is worth remembering that simply turning off a PC at the back or at the wall when not in use can have a major impact on energy consumption and its environmental impact.


Beyond the above "good housekeeping" user initiatives, there are a number of more fundamental steps that can be taken to significantly decrease the environmental impact of computing. These mainly involve measures for reducing energy consumption, and may be grouped under the following six headings:

  • Lower power hardware
  • Virtualization
  • Cloud computing
  • Energy efficient coding
  • Improved repair, re-use, recycling and disposal
  • Less pollutant manufacture

The following sections explore the above measures in more detail.


When, in 2005, Intel announced the new computing mantra to be "performance per watt" (rather than processor speed) green computing in general and lower power hardware in particular started to go mainstream. PCs can be made to use less electricity by using a lower power processor, opting for onboard graphics (rather than a separate graphics card), using passive cooling (rather than energy consuming fans), and either a solid state drive (SSD) in place of a spinning hard drive as the system disk, or else a 1.8" or 2.5" rather a than 3.5" conventional hard drive.

For some time, VIA has been promoting low-energy computing with the development of its lower power processors. For example, in 2006, VIA launched a lower-power (7.5W) "carbon free CPU" - the C7-D - as used in many lower-power mini-itx PCs. The C7-D is carbon-offset via a range of VIA partner initiatives involving reforestation, alternative energy use and energy conservation. For more information see the VIA C7-D Processor Website.

Intel is also getting into greener desktop computing in a big way, not least with a highly energy-efficient processor called the Atom. Whilst early Atom processors were largely intended for use in ultramobile PCs and TV net-top boxes, the Atom is now to be found in some small, green desktop PCs. Indeed, using the Atom, or processors such as VIA's C7-D or Freescale's MPC5121e, several companies -- including Very PC and Tranquil PC -- have now launched energy efficient "green" PCs that consume as little as 20W of power (compared to the typical 100W to 200W of an average desktop computer).

Most recently Intel has launched a dual core Atom processor and accompanying 'Pinetrail' motherboard which can form the heart of a quite powerful PC that still uses only around 20W of power. You can watch me building a green PC using this motherboard and processor in this video.

Several mainstream manufacturers are now starting to launched relatively-low-power PCs -- or "nettops" -- usually based around an Atom processor. At the very extreme, CompuLab have even launched a tiny, noiseless "Fit PC" with a power consumption of only 5W. Hard disk manufacturer Western Digital is also highly active in the green computing arena with its range of Caviar Green low-energy hard disks. These are the first hard disks "designed to deliver power savings as the primary attribute", and achieve up to 40 per cent power savings in part by varying the spindle speed to achieve minimal energy consumption.

Very low power computers are often not able to perform some of the tasks (such as video editing and games playing) demanded of their more power-hungry current counterparts. However, being largely silent, they are more pleasant to use. They are also perfectly suited to cloud computing, as noted below.


Whilst the cost of computer processing power continues to fall, the cost of fuelling that processing capacity is rising. Energy costs indeed now exceed hardware costs over the lifetime of most business PCs, let alone servers. Corporate data centres have also been reported to be using about 1.5 per cent of the energy output of the United states. Any measure than can reduce the energy consumption of business computing is hence very welcome, and top-of-the-list in terms of the data centre is virtualization.

Virtualization is the use of computer software to simulate hardware. Within data centres, server consolidation applies virtualization in its replacement of many stand-alone physical servers with virtual servers that run as software on a small number of larger computers. To their users, virtual servers can be configured to still appear as physical machines on their network. However, via a virtualized server consolidation a company can obtain a far more optimal use of computing resources by removing the idle server capacity that is usually spread across a sprawl of physical servers. Very significant energy savings can also result. IBM, for example, is currently engaged in its Project Big Green. This involves the replacment of about 2,900 individual servers with about 30 mainframes to achieve an expected 80 per cent energy saving over five years.

To assist further with energy conservation, virtualization can take place at the level of files as well as servers. To permit this, file virtualization software is already available that will allocate files across physical disks based on their utilization rates (rather than on their logical volume location). This enables frequently accessed files to be stored on high-performance, low-capacity drives, whilst files in less common use are placed on more power-efficient, low-speed, larger capacity drives, and as discussed in more depth here.


Cloud computing is where software applications, processing power, data and potentially even artificial intelligence are accessed over the Internet. Cloud computing has many benefits, one of which is enabling anybody to obtain the environmental benefits of virtualization. Whilst most servers in company data centres run at c.30 per cent capacity, most cloud vendor servers run at 80 per cent capacity or more. By choosing to cloud compute -- and in particular by adopting online computer processing power in the form of PaaS or IaaS -- companies may therefore potentially reduce their carbon footprint.

As well as allowing server capacity to run at a more optimal energy efficiency, cloud computing can also remove the need for most users to run high-power PCs and laptops. Indeed, by opting to use SaaS applications from the cloud, one of the benefits of cloud computing is that lower power hardware becomes a more and more viable option. It is also worth noting that the use of SaaS tools may also enable more people to collaborate without the need to physically travel, in turn reducing the environmental impact of the activity.


Whilst all of the above measures are intended to permit computers to most energy-efficiently run existing applications, an alternative approach to power saving is energy efficient coding. The principle behind energy efficient coding is to save power by getting software to make less use of the hardware, rather than continuing to run the same code on hardware that uses less power. Of course combining these two approaches can lead to even greater energy savings.

For many years, writing small and efficient -- let alone energy conscious -- software has hardly been a priority given continual increases in computer processor power and storage capacity. A great deal of "bloatware" is therefore now in existence. However, with some estimates suggesting that energy efficient coding could reduce the energy consumption of data centres by 25 to 30 per cent, it is unlikely to be possible to continue to ignore electricity usage as a factor in good software design.

As discussed here by Bob Steigerwald of Intel, energy efficient coding may involve improving computational efficiency so that data is processed as quickly as possible and the processor can go into a lower power "idle" state. Alternatively or in addition, energy efficient coding may also involve data efficiency measures to ensure that thought is given in software design to where data is stored and how often it is accessed. Finally, programmers also need to write software that has what Bob terms a "context awareness" of the power state of a computer and its selected power policy, and so that it can behave appropriately.


In the United Kingdom, from January 2007 the Waste Electrical and Electronic Equipment (WEEE) Regulations 2006 were introduced. These implement European Union Directive 2002/96/EC, and aim to reduce the quantity of waste from electrical and electronic equipment, as well as to increase its re-use, recovery and recycling.

The WEEE Regulations place obligations on manufacturers and retailers to recycle products, and have significant implications for all IT departments when disposing of any computer equipment. The regulations also make all electrical retailers responsible for the proper disposal of old computer equipment.

Of course, even better than more effective disposal is hardware repair, the recycling of old computer hardware into a second-use situation, the re-use of components from PCs beyond repair, and/or the less frequent upgrading of computer equipment in the first place. Personal computers are one of the most modular and hence the most repairable products purchased by individuals and organizations. Indeed, whilst it is virtually impossible to make major repairs to most other domestic and office appliances - let alone to reuse components from, say, a failed dishwasher - repairing computers and re-using at least some parts from broken PCs is in practical terms very easy indeed. The problem is that both companies and many individuals have got into the habit of changing their computers every 2-3 years. However, with the practical benefits of hardware and software "advances" rapidly diminishing, such a rapid upgrade cycle is no longer required, and hence increasingly hard to justify in either cost/benefit or environmental terms.


A great many hazardous chemicals - including lead, mercury, cadmium, beryllium, brominated flame retardants (BFRs) and polyvinyl chloride (PVC) - are used to make computers. By reducing the use of such substances, hardware manufacturers could prevent people being exposed to them, as well as enabling more electronics waste to be safely recycled. Indeed, as Greenpeace note in their 2008 Guide to Greener Electronics, "until the use of toxic substances is eliminated it is impossible to secure 'safe' recycling . . . [with] . . . the presence of toxic substances in electronics [perpetuating] the toxic cycle - during reprocessing of electronic waste and by using contaminated secondary materials to make new products".

Whilst less pollutant computer manufacture is something that clearly needs to be undertaken by those companies who make the hardware in the first place, individuals and organizations can play an important role in their choice of new hardware. Indeed, as argued by the Silicon Valley Toxics Coalition (SVTC), "electronics companies say that customer demand is the single most compelling driver for them to make changes in their products". Both individuals and organizations are therefore in a position to influence the number of hazardous chemicals they purchase in the form of computing equipment. Information tools to assist with this include Greenpeace's aforementioned Guide to Greener Electronics, as well as the SVTC website. There are also some interesting new products starting to become available, including some computers from Asus that have substituted bamboo for some of the plastics used in the casing


When it comes to being green, computing as both an industry and a broader human activity is unusual in that it may be both part of the problem and part of the solution. Indeed, as Intel highlighted in their excellent 2007 white paper on Advancing Global Sustainability Through Technology, the microprocessor has the potential to become one of the "most energy-efficient, emission-reducing devices ever created".

There are three basic ways in which computer application can assist with reducing humanity's environmental impact. These comprise:

  • Increasing business efficiency
  • Dematerialization, and
  • Travel reduction

According to Intel, microprocessors can increase business efficiency by enabling economies to scale in clean or at least cleaner ways, and by reducing the wastage of natural resources (for example through better logistics co-ordination so that goods are shipped a minimum number of times). Indeed, citing a variety of evidence including this Report on Digital Prosperity, they go on to claim that carbon emissions are already lower than they would have been without the recent development of computing and related communications technologies. In other words, whilst computing equipment may be far more environmentally unfriendly in its manufacture, use and disposal than it could be, the productivity gains that it has allowed modern economies to make have already in part off-set what would have been an even larger growth in emissions.

Beyond helping businesses be more efficient, computing developments -- and in particular those associated with the use of the Internet -- can help us to be greener by enabling dematerialization. This refers to the replacement of physical items or physically manipulative services with purely digital equivalents. Any such move from "atoms to bits" removes the need to manufacture and to transport physical goods, and hence saves natural resources. Already music, video, computer software, tickets and a range of financial and business paperwork have started to become digital commodities. The environmental benefits of such a transformation can also be significant. For example, as Intel note, reading the news on a mobile computer results in the release of 32 to 140 times less carbon dioxide and other gases (including nitrogen and sulphur oxides) than consuming a hardcopy newspaper.

People as well as goods can effectively also be dematerialized as and if computer application enables travel reduction. Most obviously, many face-to-face meetings (if granted not all face-to-face meetings) can now quite effectively be replaced with audio or video conferences. With many company resources (including e-mail, intranets and SaaS applications) now often available any time, any where online, teleworking is also a highly resource-efficient possibility. This does not mean that everybody can or should be working at home or ceasing to engage in business travel. However, if most people with access to the latest Web 2.0 tools reduced the number of business trips made and worked at home even a day a week, the environmental savings made would be very significant.

As Intel note, studies regarding the environmental impact of teleworking also suggest that the reduced need for office space that results yield even bigger savings that the obvious savings made through reduced travel. To cite their white paper, "existing and implemented use of flexible work indicates that 10 million 'flexiworkers' in Europe could save more than 11 million tons of [carbon dioxide] emissions through office space and commuting savings. Thirty million flexiworkers could save more than 34 million tons" (Intel, 2007: p.7).

Of course Intel is not alone in recognising the potentially positive environmental impact that computing may have on human activity. ETNO -- the European Telecommunications Network Operators Association -- has had an environmental charter since 1996, and has published a detailed report entitled Saving the Climate @ the Speed of Light.

The above report highlights a range of startling statistics. These include the potential for the replacement of 20 per cent of EU business travel with video conferencing to save 22.35 million tons of carbon dioxide a year, and for online phone bills and tax returns in the EU to potentially save another 686 million tons of emissions. (ENTO, 2007: p.38). Indeed, ETNO note that already some companies are starting to replace their "travel departments" with "meetings departments" that facilitate both real and virtual gatherings.


Whilst the performance and the breadth of application of computers is increasing, so too is our awareness of the cost and scarcity of the energy required to power them, as well as the materials needed to make them in the first place. However, because computing developments can enable individuals and businesses to adopt greener lifestyles and workstyles, in terms of the environmental debate computing is definitely both part of the problem and part of the solution.

Through more environmentally aware usage (such as more effective power management and shut-down during periods of inactivity), and by adopting current lower power technologies, computers can already be made significantly more energy efficient. Indeed, just as we now look back and wonder why automobiles a decade or two ago used to guzzle so much petrol, in a decade's time we will no doubt be staggered that a typical desktop PC used to happily sit around drawing 100-200W of power every hour night and day, and when accomplishing no more than displaying a screensaver.

The computing industry is more prepared and far more competent than almost any other industry when it domes to facing and responding to rapid change. Environmentally it is not a good thing that most PCs -- especially in companies -- have typically entered a landfill after only a few years in service. However, this reality does at least mean that a widespread mindset already exits for both adapting to and paying money for new computer hardware on a regular basis. Hence, whereas it took decades to get more energy efficient cars on the roads, it will hopefully only take a matter of years to reach a state of affairs where most computers are using far less power than they needlessly waste today.

Green image

Green computing attempts to have a reduced impact on
the environment.


Green Computing

Building a Green PC

Shut Down and Switch Off

logo line
Twit Link