Marinus blows out to $5bn — but backers say it’s still worth it.
The cost of building the first stage of the Marinus Link project has blown out to over $5 billion, following a major reassessment by project developers.
The updated estimate includes $3.89 billion for the now single 750 MW undersea transmission cable and $1.14 billion for Tasmania’s North West Transmission Developments (NWTD).
This latest revision, required as part of the Regulatory Investment Test for Transmission (RIT-T), puts the total project cost about $230 million higher than previously forecast.
Independent analysts EY Parthenon estimated that Marinus could deliver $1.06 billion in emissions reduction benefits by allowing Tasmania to export excess hydropower and displace coal generation on the mainland.
A separate report by FTI Consulting projected consumer savings across the National Electricity Market, including annual bill cuts of $113 for Tasmanian households and $68 for Victorians—though critics say the modelling has serious limitations.
Project backers argue that wholesale electricity savings will outweigh added transmission charges, but those extra network costs are not included in the estimated bill reductions.
“These findings show that as the energy market continues to evolve, Project Marinus remains crucial for energy affordability, security, and decarbonisation.”
MLPL CEO Stephanie McGregor
The debate over Marinus has intensified ahead of Tasmania’s July 19 election, with both major parties showing conditional support while critics demand transparency on the project’s full cost to Tasmanians.
With a federal environmental decision delayed until July 25 and a final investment decision still pending, the project's future remains uncertain, despite its central role in Australia's clean energy plans.