On 7 January 2026, the Australian Energy Regulator published its Transparency Review of AEMO’s Draft 2026 Integrated System Plan (ISP) (‘transparency review report’). The transparency review report assessed whether AEMO adequately explained how it derived key inputs and assumptions, and how key inputs and assumptions contributed to the outcomes in the Draft 2026 ISP. This review was not intended to assess the outcomes of the Draft 2026 ISP, or the merits of AEMO’s decisions.
The AER concluded that AEMO adequately explained most of its inputs and assumptions, and how they contributed to Draft 2026 ISP outcomes. The report also identified some aspects of the Draft 2026 ISP where more explanation would improve transparency.
The Addendum to the Draft 2026 ISP provides further explanatory material on the following matters raised in the Transparency Review report:
- Operational output changes from the 2024 ISP
- Contribution of key inputs to the outcomes of the proposed optimal development path (ODP)
- Process for determining scenario least-cost development paths
- Changes in consumer battery capacity
- Application of build limit constraint in the constrained delivery sensitivity
- Results for the Northern Transmission Project.
Consultation process and timeframes
AEMO has consulted with stakeholders on the Draft 2026 ISP. AEMO now invites stakeholders to provide written submissions on the content of this Addendum to the Draft 2026 ISP. Submissions should be provided in PDF format to [email protected] by 6pm (AEST), Wednesday, 15 April 2026.
Submissions
Please note that submissions have been published (apart from confidential material) as per AEMO’s consultation submission guidelines.
AEMO will address submissions on the Addendum in the 2026 ISP Consultation Summary Report which will be published in parallel with the final 2026 ISP.
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Consultation documents