by Dr. John Spencer, Head of Business Development (Education)

Many measures have been produced to cost information and communication technology (ICT) in UK schools. These include capital equipment replacement cycles, the cost of software licensing and upgrades, the cost of the software applications themselves and the cost of technical support.

All of the above contribute to the total-cost of ownership (TCO) of school ICT and collectively is a cause for concern to BECTA, the government’s educational quango for ICT.

BECTA’s report on TCO released in May 2006 pointed out that savings of up to 60% are possible if schools use Open Source Software in the place of proprietary software.

Our investigation took on a different dimension when we realised that those schools with large Open Source commitments also tend to deploy on non-traditional hardware configurations.

We decided to compare the power consumption of two technical models of computing in schools, one we shall call the "Conventional Model" and the other the "Green Model".

To produce our figures we first have to define the models, detail their power consumption and specify their use.

Secondly we will base our figures on the secondary education sector as they are the biggest users of computers in education.

It is worth noting at this stage that the secondary sector is more homogeneous than the primary sector and that there are approximately 5000 schools in the UK compared to a total of 59,000 registered educational establishments.

The Models

Conventional

In a 'conventional' network the workstations are regular PCs with nominally 350w psu and with either 150w 15" CRT monitors or 50w LCD 17" panels. There are typically 5 servers per school running at 700w psu each and housed in an air-conditioned (5KW) room.

These are conservative figures many schools have more powerful desktops (400w), more servers and typically air conditioning in all network rooms. CRT monitor's power consumption vary considerably. LCD panels draw between 35 and 75 w when active depending on the manufacturer.

Green

In a 'green' network workstations are thin-client terminals based on the power over ethernet model (PoE) and typically draw between 1 and 2 w per terminal. 30 thin-clients are served by one 400w terminal server.

The 5 network servers used in the Conventional Model are consolidated into one 800w server running virtualised operating systems and are liquid cooled.

We assume the same 50w LCD monitors as in the 'conventional' network. Lower power consumption means that no air conditioning systems are required.

Parameters

Numbers of schools and computers

We worked on a basis of 5000 secondary schools (including independent schools) in England, Wales, Scotland and Northern Ireland, and 200 PCs per school. ^1,2,3,6

There is no consolidated record for the entirety of this sector but the figure of 200 PCs per school is conservative.

Cost of electricity

The cost of electricity is set at 6p per Kwhr – this is the mode cost in the UK. Local Authority schools have had electricity supplied at a discounted rate, a practice which ceases in 2007 when they will pay full commercial prices.⁷

The carbon dioxide to KWhr was set at 650g of carbon dioxide per kilo watt hour of electricity produced - this is the mode taken from power generation sources in the UK. ⁸

Typically gas-fired power stations produce 440g of CO2 per KWhr, oil-fired stations produce 650g per KWhr and coal-fired stations 950g per KWhr. At present Local Authority schools have preferential rates for electricity costs allowing them to absorb high electricity consumption. This is due to end in 2007.

Usage

A schools network servers (and required air conditioning) run 24/7, 365 days a year.

We can assume that workstations are switched on for 8 hrs per day, 5 days per week for about 0.7 of a year to allow for holidays and weekends.

Calculation of costs & emissions

Using these parameters we calculated the following figures for our notional, average secondary school.

Conventional Model

If we scale these figures up to include the full population of 5000 schools in the UK we arrive at nearly £100 million spent on electricity per annum and 1 million tonnes of carbon dioxide released.

Green Model

The Green Model therefore represents a 89% saving in the cost of electricity and a 78% reduction carbon dioxide emissions when compared to the Conventional Model.

Future projections

The trend based on the conventional model is for the number of computers per school to rise.

The stated aim of many authorities is to have one computer per child. In addition the exponential growth of the interactive whiteboard in all education sectors is set to achieve one in every classroom.

Bearing in mind that an interactive board runs from a conventional PC with a 600w projector and that there are over 50,000 primary schools in the UK we can predict a ten fold increase in power consumption with concomitant carbon increases over the next five years.

The green model proposed is essentially a model to rework the conventional model with the absolute minimum of changes in the resources available and the way in which they are used. It is worth mentioning that a third model can be deployed which takes the concept of reduced power consumption further.

A school might well decide to make use of applications and storage provided over their Internet connections and for personal computing use embedded applications either on the thin-clients or on personal usb -keys. In this scenario the school 'network' dispenses with on-site servers completely and uses only the PoE terminals. Such a setup can easily be powered by renewable sources of energy such as wind turbines or solar panels thus reducing the carbon costs to near zero.

References

1. The UK Education Disk
2. The Education Publishers Council
3. Pupils in Scottish Schools
4. Independent School's Council
5. The Publishers Association
6. DfES
7. Carbon dioxide - www.dft.gov.uk and www.esru.strath.ac.uk
8. ElectricityCosts