Loss factors and regional boundaries
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% 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 delivery of adequate supply to meet prevailing demand and maintain the power system in balance. In practical terms, this means 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 transmission and distribution loss factors. Loss factors are calculated and fixed annually to facilitate efficient scheduling and settlement processes in the NEM.
AEMO determines Marginal Loss Factors for each financial year, and updates are made on a quarterly basis throughout the period to reflect new and revised connection points. The Marginal Loss Factors being applied in AEMO’s market systems are updated daily and published through NEMWEB.
AEMO publishes Distribution Loss Factors for each financial year as advised by the relevant Distribution Network Service Provider, and updates are made required.
2020-21 Financial year
2019-20 Financial year
2018-19 Financial year
2017-18 Financial year
2016-17 Financial year
2015-16 Financial year
2014-15 Financial year
2013-14 Financial year
2012-13 Financial year
2011-12 Financial year
2010-11 Financial year
2009-10 Financial year
2008-09 Financial year
Archived loss factor documents may be obtained upon request from the AEMO Information & Support Hub.
Indicative extrapolation input data for 2022-23 Marginal Loss Factors
AEMO conducted an indicative extrapolation study to assist generators in determining whether the historical generation data used by AEMO is reasonable for the 2022-23 MLFs calculation.
Indicative extrapolation input data for 2022-23 Marginal Loss Factors:
Indicative extrapolation archive
Indicative extrapolation input data for 2021-22 loss factors (243 KB, pdf) Indicative extrapolation input result for 2021-22 loss factors (148 KB, xlsx) Indicative extrapolation input data for 2019-20 loss factors (458 KB, doc)
Indicative extrapolation results for 2019-20 loss factors (106 KB, xlsx)
Indicative extrapolation input data for 2018-19 loss factors (391 KB, pdf)
Indicative extrapolation results for 2018-19 loss factors (100 KB, xlsx)
Indicative extrapolation input data for 2017-18 loss factors (391 KB, pdf)
Indicative extrapolation study results for 2017-18 loss factors (100 KB, xlsx)
Indicative extrapolation input data for 2016–17 loss factors (486 KB, pdf)
Indicative extrapolation study results (78.9 KB, xlsx)