As electricity flows through the transmission and distribution networks, energy is lost due to electrical resistance and the heating of conductors. The losses are equivalent to approximately 10 percent of the total electricity transported between power stations and market customers.
Energy losses on the network must be factored in at all stages of electricity production and transport to ensure the deliver of adequate supply to meet prevailing demand and maintain the power system in balance. In practical terms, this means that more electricity must be generated than indicated in simple demand forecasts to allow for this loss during transportation.
The impact of network losses on spot prices is mathematically represented as transmissions and distribution loss factors. Loss factors are calculated and fixed annually to facilitate efficient scheduling and settlement processes in the NEM.
Methodology and Guides
Methodology for Calculating Forward-Looking Transmission Loss Factors
Treatment of Loss Factors
Proportioning of Inter-Regional Losses Within Regions
Methodology For The Averaging Of Transmission Loss Factors
Transmission Loss Factors
Regional Boundaries and Marginal Loss Factors the 2014-15 Financial Year
Regional Boundaries and Marginal Loss Factors for the 2013/14 Financial Year
Regional Boundaries and Marginal Loss Factors for the 2012/13 Financial Year
Regional Boundaries and Marginal Loss Factors for the 2011/12 Financial Year
Regional Boundaries and Marginal Loss Factors for the 2010/11 Financial Year
Regional Boundaries and Marginal Loss Factors for the 2009/10 Financial Year
Regional Boundaries and Marginal Loss Factors for the 2008/09 Financial Year
Current Transmission Loss Factors
AEMO calculates and publishes marginal loss factors on 1 April each year. For new connection points established after this time AEMO does not routinely publish updates of the loss factors document. However the attached list of MLFs in Excel format is updated whenever an MLF for a new connection point is calculated.
Distribution Loss Factors
Distribution Loss Factors for the 2014/15 Financial Year
Distribution Loss Factors for the 2013/14 Financial Year
Distribution Loss Factors for the 2012/13 Financial Year
Distribution Loss Factors for the 2011/12 Financial Year
Distribution Loss Factors for the 2010/11 Financial Year
Distribution Loss Factors for the 2009/10 Financial Year
Distribution Loss Factors for the 2008/09 Financial Year
Archived loss factor documents may be obtained upon request from the AEMO Information & Support Hub.
Provision of Indicative Marginal Loss Factors
Interested parties may on occasion require marginal loss factors (MLFs) under conditions that differ from the Forward Looking Loss Factor (FLLF) methodology. Some examples may be as follows:
- A proponent may wish assess the potential impact on published MLFs if a generating unit is installed or upgraded at a particular connection point.
- A market customer may wish to assess the impact on the published MLF at a connection point without the contribution of a nearby generating unit.
- A market participant may wish to assess the MLF of an embedded generator for which AEMO does not normally calculate and publish an MLF.
In order to assist interested parties with such requests, AEMO currently provides a service to calculate indicative MLFs under non-standard assumptions for a nominal fee.
The following document provides details of the indicative MLF calculation process, including fees and data requirements.
For further information on this document, please contact Ramitha Wettimuny
Indicative extrapolation input data for 2015/16 loss factors
To assist generators in determining whether the historical generation data used by AEMO is reasonable, AEMO conducted an indicative extrapolation study.