Type
Sector
Electricity
Segment
Transmission
Issue date

Today we commenced consultation on our Supplementary Draft Decision for Marinus Link’s Stage 1, Part B (Construction costs) revenue proposal. 

We are taking a two-step approach in making a determination for this proposal, to support consumer engagement and the timely delivery of Project Marinus. This includes an Initial Draft Decision limited to two market tested work programs published in May 2025, with the remaining cost elements assessed in the Supplementary Draft Decision. 

Our role is to assess the efficiency and prudency of the forecast construction costs to ensure consumers pay no more than necessary.

Our Supplementary Draft Decision does not accept Marinus Link’s proposed capital expenditure of $3,495.3 million ($2023). Instead, we substitute an alternative estimate of $3,316.9 million ($2023), 5.1% lower than Marinus Link’s proposal. The primary driver of the lower estimate is a reduction in the proposed risk allowance of $361.5 million with an alternative allowance of $198.7 million as we have identified areas where further evidence from Marinus Link is required.

Our Supplementary Draft Decision accepts the balance of works costs of $909.1 million ($2023) and updated costs following the Initial Draft Decision for converter stations, $776.7 million ($2023), and high voltage direct current cables, $908.6 million ($2023).  

Our Supplementary Draft Decision also includes our positions on the application for the capital expenditure sharing scheme and cost pass throughs. 

We expect to make our Final Decision on Stage 1, Part B (Constructions cost) in February 2026. 

Go to the Supplementary Draft Decision Paper 

 

 

Background

Marinus Link is a component of ‘Project Marinus’, a single actionable project under AEMO’s 2024 Integrated System Plan. Stage 1 of Project Marinus will deliver a 750 MW interconnector (Marinus Link) between Victoria and Tasmania and associated network upgrades under the North West Transmission Development

On 29 November 2024, the AER received the Stage 1, Part B (Construction costs) proposal for the 2025-2030 regulatory period.