We recommend working through the following five steps when implementing a green desktop computing initiative.
This process is informed by several years of experience working with Colleges, departments and museums at the University. It is designed to encourage you to implement a robust approach to power management and in so doing help others achieve similar results.
Whilst we recommend working through the full programme, if you have already decided to execute a project to reduce desktop power consumption then the following quick start can be used as an implementation check-list.
In order to demonstrate the power and CO2 savings made, you need to implement power monitoring from the outset.
Substantial power savings can only be made by powering down desktop PCs when they are not needed. Ideally this is done simply through cultural change - desktop users turn off their PCs at the end of the day to support an organisational goal of reducing unnecessary power consumption.
However, various factors can make it hard to achieve the desired level of compliance. To help this, a number of technical tools are available to help. In particular the PowerDown tools, developed at Liverpool, offer a low-cost and effective automatic power-down scheme for Windows networks. There are also a number of commercial tools (see an Oxford assessment of the NightWatchman, PowerMAN and Surveyor products).
Two of the most common objections to powering down of idle PCs are that it takes a long time for the PC to start the following morning (wasting time), and that PCs need to be turned on to allow remote access (e.g. to work from home).
The Wake-on-LAN service overcomes these challenges to change by enabling desktops to be automatically powered up on a schedule, or on-demand.
Here we consider energy consumption with respect to two policies for managing desktop computers:
We calculate financial costs and greenhouse gas emissions over a year and make the following assumptions:
To calculate the total electrical energy consumed over a year with policy 1 we simply multiply the power the computer and monitor run at by the total time they are used over a year. So for our typical computer the sum would be: 0.105 kW x 24 hours x 365 days = 920 kWh. To estimate the financial costs we simply do 920kWh x 12p/kWh = £110. To estimate greenhouse gas emissions 920kWh x 0.537 kg CO2/kWh = 494 kg CO2.
The tables below use this calculation to show costs and greenhouse gas emissions for different stocks of computers. Table 2 also shows savings that might be achievable with a shift from policy 1 to 2:
|Policy 1 to 2
|Policy 1 to 2
The figure of 1 470 000 computers is included as this is the estimate for the total number of desktop computers in UK Further and Higher Education, according to the SustainIT Report, P. James et al, 2009
These calculations are meant to illustrate the differences between the two policies. The actual savings that an organisation can achieve will be dependent on local conditions:
It is therefore important to use local measurements to estimate how much electricity consumption can be reduced. (The easiest way to estimate the power your computers when switched on is to use a plug-in power meter).
Here we provide a variety of references to resources that range from the inspiring TED talks to highly detailed and specific papers on green computing. Our emphasis in selecting these resource is two-fold: developing low-carbon technology is a huge area of endeavour and there are many exciting projects emerging (2) IT professionals have a very important role in developing solutions, and green desktop computing (office and personal computing) can be achieved today.
Many groups have already achieved significant results but the lesson is clear: the problem is not as simple as it might first appear. Green desktop computing has often been cited as low-hanging fruit in terms of energy reduction. We suspect this assertion came about before people actually tried to tackle the problem in a realistic and complex IT environment. The main problem being that in the end in most situations power management is the responsibility of large numbers of individuals who have not typically had to change the way they work to consider energy consumption.
3.1. Monitor power management and switch computer on remotely
We recommend all groups first set up what we call FiDo software to plug into the University power management monitoring and wake on LAN facilities. Once installed you will have secure access to a graph of how many computers are switched on during the day and night, and the ability to switch computers on remotely:
Figure images/monitoring-service.jpg [Data from the power management monitoring facility installed at the Computing Services (OUCS).]
3.2. Safely and reliably power down computers automatically
The next step is to look at tools that safely and reliably put computers to sleep (S3), hibernate (S4) or off (S5) automatically. There are many ways to achieve this:
If you have experience of any of these tools, or would like help in negotiating licenses with commercial vendors please send an email to OUCS at: firstname.lastname@example.org.
3.3. Monitor electricity meter readings
The Environmental Change Institute has developed two tools to help analyse energy use. The first tool polls and compiles data from a specific networked meter, then uses the Simile software to produce a graph embedded in a web page, as below:
Figure images/electricity-meter-readings.jpg [Electricity meter readings at the Computing Services department.]
If you are interested in using a graph like the one above please send an email to email@example.com.
The ECI has also developed SMEasure a web-based building energy analysis and carbon monitoring tool helping businesses save money and reduce carbon emissions.
Figure images/smeasure-screen.jpg [Screenshot of the SMEasure tool developed by the ECI group at the University of Oxford.]
To learn more about the SMEeasure tool please get in touch with the SMEasure team directly.
To achieve this we recommend:
We encourage you to write up your initiative and publish it on your groups web site as this will help others learn from your experiences. Here we list a selection of case studies from different IT environments (departmental, College and museum) where a mixture of commercial, in-house and tools provided by OUCS have been implemented.
Most importantly the case studies listed here are currently the best examples of green IT initiatives at Oxford, each group has already achieved real and significant energy savings because of their efforts.
If you have published a green desktop computing initiative case study please let us know by sending an email to firstname.lastname@example.org.