CO2 savings achieved by the chosen array since it was connected to the live data feed is shown on the LHS of the display.  The savings achieved in the relatively short time since a website visitor has opened up the live data feed ("this session") are also displayed.

Only a small amount of fossil fuel is involved in the maintenance and operation of a PV array. The electricity generated by PV is usually considered emissions free. The CO2 savings are based on the amount of grid electricity displaced by the PV.  

Electricity supplied from the SE Queensland electricity grid is generated mainly by coal fired power stations. Electricity from gas fired plant and from renewable sources also forms part of the mix. The Commonwealth Government publishes CO2 emission factors covering the generation of grid electricity consumed within each State. The CO2 Savings for the chosen PV array are obtained by simply multiplying the "Total Energy" by the emission factor applicable to Queensland.

All plant and equipment has embodied energy and hence greenhouse gas emissions associated with its manufacture and installation. Information is still being gathered and analysed on the embodied energy in different types of power generation plant. Meanwhile an assumption is made that the embodied energy associated with a PV installation, expressed as kg CO2 per kWh of output, is not a lot different to that for other forms of power generation. Consequently the CO2 savings calculator does not, at this stage, considered embodied energy and related emissions.