Greenhouse inventory and reporting
Western Power reports its greenhouse gas emissions to the Department of Climate Change and Energy Efficiency in accordance with the National Greenhouse and Energy Reporting Act 2007. Greenhouse gases other than carbon dioxide, for example methane and sulphur hexafluoride, are required to be reported in carbon dioxide equivalents (CO2-e).
Greenhouse gas sources are reported as Scope 1 direct emissions or Scope 2 indirect emissions.
Direct emissions can be attributed to a Western Power activity that emit one or more of the reportable greenhouse gases. For example, burning of fuel for mobile electricity generators operated by Western Power.
Indirect emissions are due to consumption of electricity and the associated emissions that occur at a power station. For example, the emissions from a power station as a result of generating electricity to provide lighting for homes.
The majority of Western Power's reportable emissions are indirect emissions.
Reporting information 2010/11
Direct emissions were predominantly due to fuels consumed for transport (15,734 t CO2-e), the Ravensthorpe Power Station (1,576 t CO2-e), mobile generators (870 t CO2-e) and emissions of sulphur hexafluoride (3,181 t CO2-e), which is an insulating gas used in electrical switchgear. Smaller sources included onsite disposal of wastewater and consumption of liquid fuels, natural gas and acetylene in stationary plant and forklifts.
Indirect emissions were dominated by electricity purchases (15,397 t CO2-e) and network losses (941,376 t CO2-e), commonly referred to as line losses. Line losses represent electricity lost, mainly as heat during transmission and distribution and electricity used in network infrastructure. In 2010-11, line losses equalled 6.44% of electricity sent through the network, which equates to 96.2% of our total greenhouse gas emissions.
In the past year, direct emissions remained static, with a decrease in mobile generator use offset by increases in consumption from the Western Power vehicle fleet and the Ravensthorpe Power Station. Increased electricity consumption by both customers and Western Power and increased line losses lead to higher indirect emissions.
