NEM Reform Program Initiatives

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.


Frequently asked questions

  • What is changing with Basslink?  

    Basslink is transitioning from a Market Network Service Provider (MNSP) to a regulated Transmission Network Service Provider (TNSP) from 1 July 2026.

    This means it will operate as a regulated interconnector, similar to other interconnectors in the NEM and will no longer be treated like a generator in dispatch systems. Market and settlement processes for Basslink will also align with standard TNSP arrangements.

  • Why is Basslink being converted to a regulated interconnector?  

    The conversion of Basslink to a regulated interconnector follows the Australian Energy Regulator (AER)’s Final determination on 27 February 2026 and is intended to improve market transparency and consistency, reduce operational and settlement risks and supports more efficient operation of the NEM.

  • When will the change take effect?  

    Basslink will:

    • Transition to TNSP: 1 July 2026
    • Cutover event: 30 June to 1 July 2026
  • Will there be any operational constraints at go-live?  

    Yes. Initially, northbound flow (TAS to VIC) may be limited to the continuous rating (~500MW) due to absence of real-time dynamic rating data for Basslink. However, once SCADA based real time ratings become available, higher capacity (up to ~630 MW overload rating) will be enabled.

  • What changes for forecasting and capacity information? 

    Previously, Basslink capacity was based on participant bids. However, once the cutover happens, capacity will rely on Network Outage Schedule (NOS) submissions from APA Group and real time SCADA data when available.

  • Will Basslink be included in the SRA process?  

    Yes, Basslink will be included in the quarterly SRA process commencing from the July – September 2026 quarter onwards.

  • When can participants start engaging with Basslink SRAs?  

    Participants can begin engaging with Basslink SRAs during the auction window from 1 to 15 June 2026, covering the July–September 2026 quarter as well as future auction periods.

  • Can participants submit SRA bids and offers during testing?  

    Yes, during the 1 June to 15 June auction window, participants can test SRA bids and offers in the pre-production environment to familiarise themselves with the process prior to submitting SRA bids and offers in production. However, auction results will only be finalised after auction close on 15 June at at 14:00 AEST.

  • Will there be sample settlement or Inter-Regional Settlements Residue (IRSR) reports during testing?  

    Sample statements and mock outputs may be provided where available to support participant testing. Details will be communicated through updates at AEMO’s Industry Forums.

  • What will happen during the cutover period?  

    During the cutover period, AEMO will coordinate a transition process with Basslinks owners APA Group, which will include a planned outage, system and SCADA updates, registration and constraint changes, followed by validation activities and a controlled return to service.

Implementation toolbox

Relevant links

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