On 21 November 2025, the AER published AEMO's 2025 Forecasting Best Practice Compliance Report following the option in section 5.2 of our Forecasting Best Practice (FBP) guidelines.
In our review, we identified that AEMO submitted the 2025 Integrated System Plan (ISP) compliance report 44 business days after publishing the ISP Methodology. This was 24 business days later than the required timeframe.
The issue is with delivery time of the compliance report, not with the content or quality of the ISP Methodology itself. AEMO requested for an extension prior to the non-compliance. However, under section 5.2 of the FBP guidelines, the AER is not able to grant an extension to the compliance report submission date.
During the review, we also noted several inconsistent references within the compliance report.
On 14 November 2025, we sent AEMO a letter with this result.
Background
Under our FBP guidelines, AEMO is required to provide us with a compliance report no later than 20 business days after the publication of the final ISP Methodology or Inputs, Assumptions and Scenarios Report. AEMO should also provide us a compliance report when publishing each Electricity Statement of Opportunities.
On 13 June 2025, AEMO wrote to the AER requesting consent to submit a combined compliance report for the 2025 ISP Methodology and 2025 Inputs, Assumptions and Scenarios Report. This was due to the proximity of the release of the documents and similarity of the included content.
On 21 July 2025, the AER acknowledged the delay and advised that the AER could not grant an extension under section 5.2 of the FBP guidelines. As a result, the delayed submission of the compliance report for the ISP Methodology would be identified as a compliance issue.
These correspondences are published below along with the compliance report and outcome assessment letter.
AEMO provided us with its 2025 Forecasting Best Practice Compliance Report on 26 August 2025. This compliance report combined the compliance reports associated with the:
- 2025 update to the Integrated System Plan methodology, released on 25 June 2025
- reliability forecasts used in the 2025 Electricity Statement of Opportunities, released originally on 21 August 2025,
- 2025 Inputs, Assumptions and Scenarios Report , released originally on 31 July 2025.
The compliance report explored AEMO’s assessment of compliance of its actions to the requirement and considerations of our FBP guidelines.
Our assessment focused on activities related to the development of the 2026 ISP and associated forecasting activities.