Electricity Transmission Ring-fencing Guideline Review

Ring fencing guideline
Date initiated: 
2 April 2019
Effective date: 
31 January 2022
General enquiries - Ring-fencing AERringfencing@aer.gov.au


On 15 November 2019, the AER released a discussion paper to commence a review of ring-fencing arrangements for transmission network service providers (TNSPs). This paper requested input from stakeholders to inform the development of an updated Electricity Transmission Ring-fencing Guideline (guideline).

Due to the COVID-19 pandemic, this project was paused. In August 2020, we released an updated timeline for the review. However, the AER is currently reviewing the updated timeline, with an expectation that this review will recommence in the later part of 2021. Further updates will be provided as soon as possible. 

Invitation for submissions

We invited interested parties to make submissions on our discussion paper by 31 January 2020. We received nine submissions in total.


The purpose of ring-fencing is to prevent regulated businesses from:

  • discriminating in favour of their related parties to disadvantage competitors operating in these markets
  • not use revenue earned from regulated services to cross-subsidise unregulated or contestable services.