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The Australian National University

Facts & findings

Lecturer writing on a white board
Firstly we will explain power, energy and the associated units and then relate the energy consumption to cost, dollars, and carbon dioxide emissions.

Power and energy

Energy is the rate at which work is done. We will limit our explanation to electrical energy, which is the rate at which work is done with the use of electricity. ICT devices consume electricity and produce work for us (the calculations that your PC or device does for you), as well as heat energy which is dissipated in the form of heat.

How does use of ICT cause carbon emissions?

Every Unit of electricity generated causes carbon dioxide emissions (CO2e) in the atmosphere. So the more electricity used, the more carbon dioxide emissions are put into the environment. Information and Communication Technology Devices at the ANU contribute in a large manner to this electricity consumption and hence carbon dioxide emissions.

Watt: Is the Unit of Power in the International System of Units. It is defined as one joule per second.

Kilo Watt Hour (KWh): Is the Unit of Energy that most of us see on our electricity bill. If a device has a power rating of 200 Watts and is on for 10 Hours, then it consumed 2000-Watt Hours or 2kWh.

Emissions factor

In Canberra, the emissions factor is 0.9. That means for every 1kWh of electricity consumed, there will be 0.9 kg of carbon dioxide emissions.

ICT energy consumption: some facts

Since August 2010, the Green ICT team has been investigating the energy consumption of various ICT devices on campus. Here are some of the findings:

Annual Carbon Dioxide Emissions and Annual Energy Cost

Annual Carbon Dioxide Emissions (tonnes) Device Annual Energy Cost ($)*
6210 Data Centre’s 828,000
3.563 Server 475
1.312 Printer 175
0.625 Dell OptiPlex 83
0.450 IMac 60

* The annual energy cost is calculated at an average kWh price of 0.12 cents/kWh

Updated:  20 April 2011/ Responsible Officer:  Director, Facilities & Services Division/ Page Contact:  Systems and Information Technology