On 26 July 2023, the AER published its amendment of Transgrid’s 2023–28 revenue determination for HumeLink early works stage 1 part 1 contingent project and the associated amended models: post-tax revenue model (PTRM), roll-forward model (RFM), depreciation tracking module and capital expenditure sharing scheme (CESS) model. The AER has made this amendment under clause 6A.8.2(n) of the National Electricity Rules (NER).

On 25 August 2023, the AER published its final decision on Transgrid’s HumeLink early works stage 1 part 2 contingent project and the associated capex model and post-tax revenue model. They are published on the HumeLink early works stage 1 part 2 contingent project page.

On 6 May 2024, we published our decision on Transgrid's VNI West early works stage 1 contingent project and the associated capex model and post-tax revenue model. They are published on the VNI West early works stage 1 contingent project page.

On 2 August 2024, we published our decision on Transgrid's HumeLink stage 1 contingent project and the associated capex model and post-tax revenue model. They are published on the HumeLink stage 2 contingent project page.

In line with our final decision on Transgrid's electricity transmission network, we have updated Transgrid's return on debt for 2024-25. As a result of this update, the return on debt for 2024-25 is 4.57 per cent. This results in an X-factor for 2024-25 of -0.92 per cent. Holding other things constant, a positive X-factor implies a real revenue decrease and a negative X-factor implies a real revenue increase. The revised PTRM shows the updated X-factor.

In line with our final decision on Transgrid's electricity transmission network, we have updated Transgrid's return on debt for 2025–26. As a result of this update, the return on debt for 2025–26 is 4.63 per cent. This results in an X-factor for 2025–26 of –12.22 per cent. Holding other things constant, a positive X-factor implies a real revenue decrease and a negative X-factor implies a real revenue increase. The revised PTRM shows the updated X-factor.