AER – Final decision – Transgrid – WSB Non-contestable Project 2024–29 – Adjustment 2026–27 – Statement of Reasons – May 2026

On 31 March 2026, we received an annual revenue adjustment proposal from Transgrid relating to the Waratah Super Battery – Network augmentation and SIPS control system (WSB Non-contestable Project). 

On 1 May 2026, Transgrid submitted a revised annual revenue adjustment proposal. This revised proposal excludes the revenue adjustment related to Paired Generation Costs, which was included in Transgrid’s 31 March proposal. We expect this revenue adjustment will instead be included in Transgrid’s annual adjustment proposal in 2027.

Transgrid’s proposal included routine adjustments to replace placeholder financial inputs determined in our final decision with actual financial inputs. It also included a non-routine expenditure adjustment. We assessed Transgrid’s proposal against the requirements in the revenue determination, EII Regulation and the Revenue determination guideline for non-contestable network infrastructure projects (Non-contestable Guideline). We have completed our assessment within 42 business days, consistent with our Non-contestable Guideline.

On 26 May 2026, in line with the adjustment mechanisms specified in the final decision, we have determined an updated quarterly schedule of payments for the WSB Non-contestable Project. We have published this updated quarterly schedule, alongside the revenue model and a statement of reasons which sets out our assessment of each adjustment contained in Transgrid’s proposal.