Marinus Link

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Marinus Link is a proposed 750 megawatt capacity high voltage direct current (HVDC) electricity interconnector, to strengthen the connection between the Australian states of Tasmania and Victoria, on Australia's National Electricity Market. Due to inflation, Marinus link was scaled back from an initial plan of 1500 MW via two cables, down to 750 MW via one cable. [1] It involves approximately 250 km of subsea cables and approximately 90 km of underground land cables. Marinus Link will also incorporate significant optical fibre capacity for system control, with the remaining capacity available to strengthen telecommunications and data connectivity between the regions. Marinus Link will be supported by approximately 220 km of high voltage alternating current (HVAC) of proposed transmission developments in North West Tasmania, known as the North West Transmission Developments (NWTD). Collectively, Marinus Link and the North West Transmission Developments are known as Project Marinus. In October 2022, authorities pledged loans for the project, as well as supporting facilities such as pumped hydro in Tasmania. [2]

Contents

Role of TasNetworks

TasNetworks owns, operates and maintains the electricity transmission and distribution network in Tasmania, delivering electricity supply to more than 295,000 residential, commercial and industrial customers, and also provides telecommunications and technology services. TasNetworks is wholly owned by the State of Tasmania and operates as a commercial business with assets of $3.5 billion. As the jurisdictional planner for the state of Tasmania, TasNetworks is progressing Marinus Link and supporting transmission developments. TasNetworks has established the subsidiary business Marinus Link Pty Ltd to progress Marinus Link.

Background

The first Bass Strait interconnector, Basslink, was constructed between 2003 and 2005, with a capacity rating of 630 MW. Basslink experienced a fault in December 2015, rendering it out of service for six months. The impact of this outage was further compounded by low water levels in Tasmania's hydroelectric power system. After the eventual restoration of service, the capacity rating of Basslink was reduced to 500 MW. [3]

In response to the resulting energy supply challenges, the Australian and Tasmanian governments commissioned a study into the feasibility of a second interconnector in April 2016. The study, often referred to as 'the Tamblyn Report', was conducted by Dr John Tamblyn, and was released in April 2017. [4] The study built on a preliminary report released by governments in June 2016, and recommended that the Tasmanian Government develop a detailed business case for a second Tasmanian interconnector.

Project timeline

Initial Feasibility Report and Business Case Assessment Phase

The Tasmanian Government, with support from the Australian Renewable Energy Agency (ARENA) on behalf of the Australian Government, directed TasNetworks to undertake a feasibility study and business case assessment for a second Bass Strait interconnector, which commenced in 2017, building on the 'Tamblyn Report'. [5] The Feasibility and Business Case Assessment phase of Project Marinus concluded with the release of the Initial Feasibility Report and the Business Case Assessment Report in December 2019. The Initial Feasibility Report showed that Marinus Link and the supporting transmission is technically and economically feasible. The Business Case for Marinus Link is positive and demonstrated that work should continue into the ‘Design and Approvals’ phase, to deliver a ‘shovel ready’ Marinus Link project in time to meet the needs of a National Electricity Market (NEM), which is undergoing a rapid and significant transition to a low emissions future.

Design and Approvals Phase

The project is currently in the Design and Approvals phase, which includes:

Progression to equipment manufacturing and construction will only commence once the necessary approvals, funding and pricing arrangements are in place, following a rigorous economic assessment. A Final Investment Decision is expected in late 2023 to early 2024, which would conclude the Design and Approvals phase, with manufacturing and construction to commence shortly after that decision is made.

The Design and Approvals phase is timed to proceed in accordance with timeframes envisaged in the Australian Energy Market Operator's (AEMO) 2020 Integrated System Plan. [6]

Manufacturing, Construction and Commissioning

The original proposal was for a 1500 MW capacity Marinus Link, planned to be built in two 750 MW stages, commissioned two to three years apart, with the first 750 MW stage in service as early as 2027. The second 750 MW of Marinus Link was to be in service as early as 2030.

In September 2023, the project was limited to 750 MW as costs increased to $3bn for that size. Ownership was 49% federal government, 33.3% Victoria and 17.7% Tasmania. [1]

Economic Analysis

The economics and regulation for Project Marinus is assessed under the Regulatory Investment Test for Transmission (RIT-T). The RIT-T is a regulatory mechanism defined in the National Electricity Rules that applies an economic cost benefit test on new electricity infrastructure proposed for the National Electricity Market (NEM).

According to the Australian Energy Regulator (AER): “The purpose of the RIT-T is to identify the credible option that maximises the present value of net economic benefit to all those who produce, consume and transport electricity rules.” The role of the RIT-T is to undertake a cost benefit analysis focusing on different technical solutions by looking in detail at engineering aspects, refining costs, considering alternate options, and staging.

Regulatory Investment Test for Transmission (RIT-T)

The RIT-T assesses the economic and technical impact of, and preferred timing for, all major network investments in the national energy market (NEM). The RIT-T process ensures regulated transmission investment decisions are in the long term interests of customers. The RIT-T process involves multiple stages, and culminated with the Project Assessment Conclusions Report, published in June 2021, which shows that Project Marinus satisfies the RIT-T.

All RIT-T reports and associated documentation have been published on the Marinus Link website.

Project Specification Consultation Report (PSCR)

The Project Specification Consultation Report (PSCR) was published in July 2018. This report and the feedback it has received has been published on the Marinus Link website.

Project Assessment Draft Report (PADR)

The Project Assessment Draft Report (PADR) for Project Marinus was published in early 2020. The PADR takes into account feedback from submissions received during the consultation period following the PSCR’s release. TasNetworks received feedback on the PADR for several months post-release, as part of the RIT-T consultation process, including briefings in Melbourne, Sydney and Hobart in early 2020. Subsequent to publishing the PADR, additional data files were made available which contain detailed information relating to PADR modelling assumptions and results.

Supplementary Analysis Report

The Supplementary Analysis Report responds to stakeholder feedback received on the PADR analysis and takes into consideration the updated scenarios, inputs and assumptions of AEMO's 2020 Integrated System Plan

Project Assessment Conclusions Report (PACR)

The publication of this report marks the culmination of the Project Marinus RIT-T process, which began in 2018 with the publication of the PSCR. The report outlines the project's stakeholder engagement activities, economic and technical analysis and results in the identification of a preferred option that maximises the net economic benefits to the NEM. The cost-benefit analysis undertaken for the Project Assessment Conclusions Report indicates that Project Marinus delivers significant positive net economic benefits to the National Electricity Market from its earliest commissioning timeline of 2027 for the first 750 MW stage, and 2029 for the second 750 MW stage. The independent modelling conducted for the PACR, completed by Ernst & Young, also supports the establishment of regulated revenue streams for Marinus Link and North West Transmission Developments, with the project providing greater benefits to the NEM than its cost.

Wholesale Pricing Report

TasNetworks engaged FTI Consulting (FTI), an independent global advisory firm, to undertake analysis on wholesale energy price benefits if Project Marinus proceeds. This work was commissioned in response to stakeholder feedback-seeking information about the customer pricing impacts and beneficiaries of Project Marinus. The independent Wholesale Pricing Report shows that Marinus Link is able to exert downward pressure on wholesale electricity prices because it enhances the NEM’s access to Tasmania’s low cost, high volume dispatchable energy resources including latent hydro capacity, high quality wind resources, and deep energy storage capability. [7]

Related Research Articles

<span class="mw-page-title-main">Hydro Tasmania</span> Government hydro electricity provider in Tasmania, Australia

Hydro Tasmania, known for most of its history as the Hydro-Electric Commission (HEC) or The Hydro, is the trading name of the Hydro-Electric Corporation, a Tasmanian Government business enterprise which is the predominant electricity generator in the state of Tasmania, Australia. The Hydro was originally oriented towards hydro-electricity, due to Tasmania's dramatic topography and relatively high rainfall in the central and western parts of the state. Today Hydro Tasmania operates thirty hydro-electric and one gas power station, and is a joint owner in three wind farms.

<span class="mw-page-title-main">Transend Networks</span> Former Tasmania state-owned enterprise

Transend Networks Pty Ltd was a Tasmanian government-owned business which operated between 1998 and 2014 as the electricity transmission network provider for Tasmania, Australia. It was formed by the disaggregation of the Hydro-Electric Commission, and ceased operation when it was merged on 1 July 2014 with the distribution division of Aurora Energy to form the combined network business TasNetworks.

<span class="mw-page-title-main">Aurora Energy (Tasmania)</span> Solar construction company in Columbia, Maryland

Aurora Energy is a Tasmanian Government-owned electricity retailer in Tasmania, Australia.

The National Electricity Market (NEM) is an arrangement in Australia's electricity sector for the connection of the electricity transmission grids of the eastern and southern Australia states and territories to create a cross-state wholesale electricity market. The Australian Energy Market Commission develops and maintains the Australian National Electricity Rules (NER), which have the force of law in the states and territories participating in NEM. The Rules are enforced by the Australian Energy Regulator. The day-to-day management of NEM is performed by the Australian Energy Market Operator.

Directlink (Terranora)Interconnector is a mixed buried and above ground 59 kilometre (37 mi) High Voltage Direct Current (HVDC) electricity transmission cable route from near Lavertys Gap (28°34′15″S153°27′8″E), 5 kilometres (3.1 mi) Southwest of Mullumbimby, New South Wales and Bungalora (28°15′20″S153°28′20″E) & connected via a 3.5km (2.2mi) AC Overhead Transmission Line to the NorthEast to the Terranora Electrical Substation (28°14′28.3″S153°30′12.7″E) @ Terranora, New South Wales New South Wales in Eastern Australia. The DC cables alternate between above ground in a galvanised steel trough and below ground with depths up to 1m.

<span class="mw-page-title-main">Submarine power cable</span> Transoceanic electric power line placed on the seabed

A submarine power cable is a transmission cable for carrying electric power below the surface of the water. These are called "submarine" because they usually carry electric power beneath salt water but it is also possible to use submarine power cables beneath fresh water. Examples of the latter exist that connect the mainland with large islands in the St. Lawrence River.

The East–West Interconnector is a 500 MW high-voltage direct current submarine and subsoil power cable which connects the Irish and British electricity markets. The project was developed by the Irish national grid operator EirGrid.

<span class="mw-page-title-main">Bell Bay Power Station</span> Former power station in Tasmania

The Bell Bay Power Station was a power station located in Bell Bay, on the Tamar River, Tasmania, Australia, adjacent to the Tamar Valley Power Station, with which it was often confused. It was commissioned between 1971 and 1974 as an oil fired thermal power station, and was converted to natural gas in 2003, after the commissioning of the Tasmanian Gas Pipeline, a submarine gas pipeline which transports natural gas from Longford, Victoria, under Bass Strait, to Bell Bay, Tasmania. As the power station's primary role was to provide system security in the event of drought for Tasmania's predominantly hydro-electric based generation system it only was rarely called on to operate, resulting in intervals of five to eight years between periods of significant use. After the commissioning of Basslink in 2006, the power station was decommissioned in 2009.

<span class="mw-page-title-main">Meadowbank Power Station</span> Power station in Tasmania, Australia

The Meadowbank Power Station is a run-of-the-river hydroelectric power station located in the Central Highlands region of Tasmania, Australia. The power station is situated on the Lower River Derwent catchment and is owned and operated by Hydro Tasmania.

The Connect Tasmania Core is the name used by the Government of Tasmania to refer to a fibre optic communications network linking all major cities of Tasmania to Victoria. The government intends to offer access to the network in order to facilitate a more competitive telecommunications industry.

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Tamar Valley Power Station is a $230 million natural gas-fired power station located in Bell Bay in the Tamar Valley, Tasmania. It is owned by Hydro Tasmania, and is immediately adjacent to the decommissioned Bell Bay Power Station, which is also owned by Hydro Tasmania.

<span class="mw-page-title-main">North Sea Link</span> Subsea electricity transmission line

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<span class="mw-page-title-main">EuroAsia Interconnector</span> Planned submarine electricity cable

The EuroAsia Interconnector is a planned HVDC interconnector between the Greek, Cypriot, and Israeli power grids via the world's longest submarine power cable, with a length of 310 kilometres (190 mi) from Israel to Cyprus and 898 kilometres (558 mi) from Cyprus to Greece for a total of 1,208 kilometres (751 mi). Connecting Kofinou, Cyprus to Hadera, Israel and Korakias, Crete, Greece, the EuroAsia Interconnector is a major Project of Common Interest (PCI) of the European Union and a priority Electricity Highway Interconnector Project as an energy highway bridging Asia and Europe. Regulatory approval of electricity interconnection between Cyprus and Greece was completed on October 10, 2017.

<span class="mw-page-title-main">Powerlink Queensland</span>

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<span class="mw-page-title-main">TasNetworks</span> State owned company in Tasmania

Tasmanian Networks Pty Limited, trading as TasNetworks, is a Tasmanian Government State owned company that is responsible for electricity transmission and distribution throughout Tasmania. It also owns and operates a telecommunications network throughout the state.

<span class="mw-page-title-main">Electricity sector in Australia</span>

The Australian electricity sector has been historically dominated by coal-fired power stations, but renewables are forming a rapidly growing fraction of supply.

The South Australian blackout of 2016 was a widespread power outage in South Australia that occurred as a result of storm damage to electricity transmission infrastructure on 28 September 2016. The cascading failure of the electricity transmission network resulted in almost the entire state losing its electricity supply, affecting 850,000 SA customers. Kangaroo Island did not lose its supply, as the Kangaroo Island power station had been built to supply the island for the contingency of a failure in the power cable under the Backstairs Passage.

Tasmania, as an advanced economy with a globally high standard of living, uses a great deal of energy. Distinctive features of energy use in Tasmania include the high fraction of hydroelectricity usage, the absence of coal-fired electrical generation, relatively light usage of natural gas, particularly for domestic use, and a wide use of domestic wood-burning stoves. Energy production through hydroelectricity has been politically contentious, and conflicts over Tasmanian hydroelectric projects were integral to the formation of Green parties in Australia and across the world.

References

  1. 1 2 Sanderson, Cosmo (4 September 2023). "Australia's 'battery of the nation' plan now hangs by just one undersea cable amid cost blowout". Recharge | Latest renewable energy news.
  2. Colthorpe, Andy (19 October 2022). "Australia's AU$20 billion transmission initiative supports Tasmania's 'Battery of the Nation'". Energy Storage News.
  3. "Tasmanian power crisis: Basslink 'design and operation inadequate'". ABC News. 25 February 2018. Retrieved 12 June 2019.
  4. Tamblyn, Dr John (April 2017). "Feasibility of a second Tasmanian interconnector, Final Study" (PDF). energy.gov.au. Australian Government, Department of Industry, Science, Energy and Resources.
  5. John Tamblyn (April 2017). "Feasibility of a second Tasmanian interconnector" (PDF). Retrieved 12 June 2019.
  6. "2020 Integrated System Plan". Australian Energy Market Operator.
  7. "Wholesale Pricing Summary Report (How do customers benefit from Project marinus?)" (PDF).