The Marinus Link interconnector has survived its latest legal challenge in Tasmania’s planning tribunal, clearing a path for the 1,500 MW undersea cable between Tasmania and Victoria – but the campaign leader opposing the Heybridge converter station has flagged a Supreme Court appeal that could stall final investment decisions and push the project’s timeline beyond the early 2030s target.
Tasmanian planning tribunal rejects appeal over Heybridge converter station
The RenewEconomy report confirms that the Tasmanian Civil and Administrative Tribunal (TASCAT) dismissed an appeal against the permit for the Marinus Link converter station at Heybridge, near Burnie on Tasmania’s northwest coast. The appeal was lodged by a local community group concerned about visual amenity, noise, and environmental impacts on the coastal zone. The tribunal’s decision allows the project’s proponents – Marinus Link Pty Ltd, a wholly owned subsidiary of TasNetworks – to proceed with detailed design and early works for the converter station, which is the Tasmanian terminus for the two 750 MW HVDC cables crossing Bass Strait.
Marinus Link is the single largest transmission project currently in development within the National Electricity Market (NEM). The full project comprises two 345-kilometre subsea HVDC cables, converter stations at Heybridge (Tasmania) and Hazelwood (Victoria), and approximately 90 kilometres of underground DC cable on the Victorian side. First energy was originally targeted for 2028-2029, with the second cable following roughly two years later. Total capital cost is estimated at $3.3-3.7 billion in 2023 dollars, split roughly 60/40 between the Commonwealth and the two state governments under a cost-sharing agreement signed in 2022.
The Heybridge site has been the focal point of local opposition since the project’s route was finalised. Residents and the “Save Our Coast” campaign have argued that the converter station’s footprint – roughly 15 hectares of industrial infrastructure including valve halls, transformers, and AC switchyards – is incompatible with the surrounding rural-residential landscape and nearby Bass Strait coastline. The TASCAT hearing examined noise modelling, visual impact assessments, and bushfire risk, ultimately finding the permit conditions adequate. That ruling is the concrete “what happened” – but the opponent’s stated intention to seek leave to appeal to the Supreme Court of Tasmania introduces a new layer of timeline risk that the market has not fully priced.
Interconnector delays compound NEM reliability risks as coal exits accelerate
That points to a broader tension: Australia’s transmission build-out is consistently running behind the retirement schedule of coal-fired generation. AEMO’s 2024 Integrated System Plan (ISP) identifies Marinus Link as an “actionable” project in the optimal development path, meaning it should proceed without regrets across most scenarios. The ISP assumes first cable commissioning by 2029-30 and second cable by 2031-32. Each year of slippage reduces the NEM’s ability to share Tasmania’s existing hydro flexibility and future pumped hydro capacity – up to 2,500 MW under the Battery of the Nation concept – with mainland states during winter peaks and dunkelflaute events.
By comparison, the Victoria-NSW Interconnector West (VNI West) and HumeLink are also facing planning and community hurdles, with VNI West’s preferred route only confirmed in mid-2024 after years of consultation. If Marinus Link’s first cable slips to 2031-32 – a plausible outcome if a Supreme Court appeal adds 12-18 months – the NEM loses roughly 750 MW of firm inter-regional transfer capacity during the critical window when Liddell (closed 2023), Eraring (scheduled 2025-27), and Loy Yang A (early 2030s) are exiting or reducing output. That capacity gap would need to be filled by additional gas peaking plant, accelerated battery deployment, or demand response – each carrying higher $/MWh costs than the interconnector’s regulated revenue stream.
My estimate: a two-year delay to first energy on Marinus Link could impose system-wide costs on the order of $200-400 million per year in higher wholesale prices and additional firming procurement, based on AEMO’s marginal value of interconnector capacity in the 2024 ISP sensitivity analysis. Those costs are socialised across all NEM consumers, not borne by the project proponents alone.
Who this affects
- Utility planner (TasNetworks / AEMO): Must re-run reliability forecasts with a probability-weighted Marinus Link timeline; if first cable slips past 2030, the 2025 Electricity Statement of Opportunities (ESOO) will likely show elevated USE (unserved energy) in Victoria and Tasmania during winter 2030-33.
- Storage / pumped hydro developer: Battery of the Nation proponents (e.g., Hydro Tasmania’s 750 MW Lake Cethana concept) lose revenue certainty – Marinus Link is the primary revenue pathway for new Tasmanian pumped hydro via access to mainland capacity markets and arbitrage.
- Policy analyst (Federal / State energy ministries): The cost-sharing agreement’s milestone payments are tied to project gates; a Supreme Court appeal could trigger renegotiation of Commonwealth funding tranches and delay the “final investment decision” gate currently targeted for late 2025.
- Transmission investor / infrastructure fund: Regulated asset base (RAB) growth for TasNetworks is contingent on Marinus Link capitalisation; a 12-24 month delay defers ~$1.5-2 billion of RAB additions, affecting credit metrics and dividend capacity for the state-owned utility.
What to watch next
- Supreme Court leave application: Whether the opponent’s legal team files for leave to appeal within the 28-day window, and the grounds – typically errors of law in TASCAT’s interpretation of the planning scheme or procedural fairness.
- Marinus Link Pty Ltd’s FID timeline: Any public update to the “late 2025” final investment decision target; a shift to H1 2026 would signal internal contingency for legal delay.
- AEMO 2025 ISP update: Whether the optimal development path retains Marinus Link as actionable with unchanged timing, or flags it as “conditional” pending legal resolution.
- Tasmanian planning scheme amendment: Whether the state government pursues a targeted scheme amendment to insulate the Heybridge site from further merit appeals – a move used for other major infrastructure but politically sensitive.
Bottom line
Marinus Link has won the tribunal battle but faces a probable Supreme Court war – and in the NEM’s current tightness, every month of delay on a 1,500 MW actionable interconnector translates directly into higher system costs and reliability risk that no other single project can fully offset.
Read the full report at RenewEconomy
Original source: RenewEconomy (Australian clean energy news)
Note: facts and figures attributed above to RenewEconomy (Australian clean energy news) reflect that outlet's original reporting. Broader context, cross-sector connections, and forward-looking scenarios reflect independent analysis by our editorial team.
About this article: Drafted by Energy Ai with AI-assisted research and writing based on public reporting, then reviewed under our editorial process before publication.
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