A multibillion-dollar undersea power cable connecting Tasmania and Victoria has finally been given the green light. After more than a decade of planning and political wrangling, the $5 billion Marinus Link Stage 1 has reached Final Investment Decision – setting the stage for construction to begin in 2026.

This landmark project aims to reshape the national electricity grid, unlocking Tasmania’s hydropower for the mainland while improving energy security and storage across the National Electricity Market.

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Key Points

• Marinus Link Stage 1 approved, construction begins in 2026 with completion expected by 2030.
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• 354km electricity and data cable connects Tasmania to Victoria, with 750MW capacity (enough power to supply 750,000 homes).
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• Backed by Commonwealth (49%), Victoria (33%), and Tasmania (17%).
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• Controversy over costs, environmental impacts, and transmission price hikes in Tasmania.

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Project Significance

Marinus Link is being positioned as a critical pillar in Australia’s transition to renewable energy. As coal-fired power stations retire, Marinus will help stabilise the grid by enabling clean, dispatchable energy to flow both ways – from Tasmania’s hydro and wind resources to the mainland, and surplus solar in reverse.

The Australian Energy Market Operator confirmed that Marinus Link is urgently required in its national infrastructure planning, underscoring its role in delivering low-cost, on-demand energy for the future.

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Further Details: Controversy and Opportunity

With Stage 1 capable of powering around 750,000 homes, the infrastructure includes not just the undersea cable but major transmission upgrades – especially in Tasmania’s North West. While touted as a nation-building project, the road to approval has been bumpy.

Environmental concerns have dogged the project, particularly over the proposed transmission lines impacting sensitive areas like Takayna and the Cam River valley. Approval from the federal government came with strict environmental conditions following extended delays and vocal criticism from conservation groups.

At the same time, the long-awaited Whole-of-State Business Case reveals significant cost impacts for Tasmania – particularly its major industrial customers, who could face average price increases of up to 45%. Even residential and small business customers are expected to see noticeable rises in transmission charges. Some critics argue Tasmania is bearing too much of the cost for a national benefit.

Nonetheless, proponents – including the federal and Victorian governments – say the long-term economic and energy market gains outweigh the drawbacks. Independent modelling forecasts up to $4.4 billion in added economic activity over the next decade, with thousands of jobs created and renewable investment unlocked across the state.

With construction beginning in 2026, Marinus Link is set to become a defining feature of Australia’s energy infrastructure – a bridge between states, between power sources, and between a fossil-fuelled past and a renewable future.