Basslink determination - participant support arrangements

On Friday 27 February 2026 the Australian Energy Regulator (AER) made a final determination on the APA Group's transmission revenue proposal for Basslink for the 2026–30 regulatory control period. AEMO anticipates that APA, upon its acceptance of the final decision, will make an application to reclassify from a Market Network Services Provider (MNSP) to a regulated Transmission Network Services Provider (TNSP).

The following arrangements are being considered by AEMO and participants are welcome to contact us to seek clarification as outlined below:

AEMO’s conversion arrangements

• AEMO is working closely with APA, as well as TNSPs VicGrid and Tas Networks to ensure the smooth transition of Basslink from a Market Network Service Provider to a prescribed Transmission Network Service Provider in AEMO systems and processes from Wednesday 1 July 2026.
• Providing the reclassification process runs according to plan, AEMO anticipates the first auction of Settlement Residue Auction (SRAs) for the Basslink interconnector will occur from Monday 1 June 2026, for the period effective Wednesday 1 July 2026 to Wednesday 30 September 2026.
• AEMO will soon launch an expedited consultation (expected Monday 9 March 2026) to include Basslink in the SRA. AEMO will notify participants of this consultation process via the NEM Reform channels and publish the relevant consultation documents on the following webpage.
• Participants can expect Basslink to be represented in AEMO’s market systems as a regulated interconnector TNSP, instead of an MNSP, from Wednesday 1 July 2026. This will include changes to daily PASA reports, Network Outage Schedule (NOS) reports, and Negative Residue Management (NRM) reports.
• Participants will have ability to test their bids, offers and internal ingestion of data for SRAs during the 1 June to 15 June 2026 window in the preproduction environment – this will mirror production during the June SRA window, and gives interested participants sufficient time to familiarise themselves before undertaking the SRA process in production.
• AEMO is also proposing to provide mock-up settlement and SRA statements, and detailed data/field specifications, which will provide participants visibility for post-auction reporting in a test environment mirroring actual production values.

AEMO will engage participants on the arrangements via NEM Reform Forums appropriate to procedures, implementation and testing.

Implementation toolbox