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Ring fencing guideline

The Ring-fencing guideline (electricity transmission) 2023 ensures the Guideline remains fit for purpose in a changing regulatory landscape and electricity market by:

  • reducing potential harms from transmission network service providers cross-subsidising competitive services with regulated revenues, primarily through strengthened legal separation obligations
  • preventing potential discrimination against competitors by transmission network service providers
  • including additional reporting and compliance obligations aligned with those in our distribution ring-fencing guideline.

The revised Guideline applies to transmission network service providers from 1 March 2023.


On 15 November 2019 the AER released a discussion paper to commence a review of ring-fencing arrangements for TNSPs. This paper requested input from stakeholders to inform the development of version 4 of the Ring-fencing guideline (electricity transmission).

Due to the COVID-19 pandemic this project was paused.

April 2022 we provided an updated timeline for the full review of the Guideline.
On 31 May the AER released an issues paper. Submissions to the issues paper closed on 22 July 2022.
On 4 November the AER released a draft Guideline and explanatory statement. Submissions closed on 16 December 2022.
On 1 March 2023 the AER released a final Guideline and explanatory statement concluding the review.