The “Marinus Link” is a high voltage direct current electricity interconnector proposed for the purpose of connecting the Tasmania and Victoria grid systems. This project will feature the use of undersea and underground cables as long as several hundred kilometers. There will be a converter station at each end of the line for handling the conversion of AC current to DC current as well as the other way around. After its final completion, the capacity of the “Marinus Link” will allow the transfer of 1500 megawatts of power.

The project would be constructed in two stages, with the first stage offering 750 megawatts, although the second stage has the same projected generation to be realized based on market conditions. The fact that the project has been designed to operate bidirectionally means that the flow of electricity goes between Tasmania and Victoria, an aspect that ensures the variability of renewable power sources can be well managed. Tasmania’s hydroelectric resources would serve as the battery for the mainland country.

Marinus Link will be approximately 345 kilometres long: 255 kilometres under Bass Strait and 90 kilometres of underground cable in Victoria. In addition to transmission of electricity, the link will also carry fibre-optic telecommunications for data and communications, as well as state-of-the-art grid control and monitoring.

Why HVDC?

The selection of the HVDC technology for the Marinus Link is a result of a number of technical advantages. Among the main advantages is the fact that this technology is much more efficient over long distances. The major disadvantage of transmitting power through alternating current is the increase in the losses of the reactive power with the distance covered. This is especially the case with underwater/underground cables.

HVDC transmission offers greater stability and flexibility of the power grid too. The HVDC transmission system is capable of dealing with power transmission from Tasmania to Victoria and from Victoria to Tasmania, which run in an asynchronous manner due to its ability to transform AC into DC and vice versa.

Renewable energy integration is yet another important benefit of this project. Solar and wind energy sources tend to be intermittent in nature, and it is necessary that this variability is balanced by the electricity network so that it remains reliable at all times. The HVDC connector that is proposed in the Marinus Link will allow the transmission of a vast amount of renewable energy from one zone to another, and this will enable the storage of excess solar and wind energy available in Victoria in Tasmania’s hydro reservoirs. These hydro supplies can be sold back to Victoria when less renewable energy is produced from other sources in Mainland Australia.

Marinus Link will use Hitachi Energy’s HVDC Light Voltage Source Converter technology. HVDC Light offers precise control of electricity flow, fast grid response, and connection with weak or isolated grids. All these are important because Australia’s electricity grid is expected to be dominated by intermittent renewable energy sources in the future.

The Role of Marinus Link in Australia’s Energy Transition

The Australian electricity sector is currently experiencing a period of dramatic change. The coal-fired electricity generators, that were the backbone of the National Electricity Market, are retiring, while wind, solar, and hydro energies continue to grow. This can be both an opportunity and a risk for the sector, as Marinus Link plays a crucial part in dealing with these challenges.

Tasmania’s hydroelectric capacity represents its special benefit. In linking Tasmania and Victoria through Marinus Link, the hydroelectric energy can supplement the intermittency of the other forms of renewable fuel in the mainland. When the sun and wind are producing excesselectricity in Victoria, the difference can be supplied to Tasmania to be stored. On the other hand, with the targeted chokepoint being the lack of enough production by forms of reneable fuel, the hydroelectric fuel from Tasmania can supplement the needed fuel.

The Marinus Link electric cable connection also has important economic and consumer implications. The increase in connection capacity between regions leads to competition in the energy market, which can assist in lowering electricity costs. The long-distance cables increase the sustainability of electricity prices, the reliability of supply in peak demand, and have long-term favorable implications for consumers. The cable connection stands out as a major investment in infrastructure, which has created employment opportunities in engineering, production, and logistical services.

The link also relates to the national transmission plan for Australia. The federal government’s Rewiring the Nation initiative has as its key aim the focusing on new transmission infrastructure that enables the integration of renewable energy and improves the reliability of the grid. Marinus Link, from energy-rich Tasmania to demand centers in Victoria, relates precisely to such plans for the future of renewable energy.

The Rise of HVDC in Australia

Marinus Link is a part of a larger phenomenon that is being witnessed in Australia regarding the transmission of power through high-voltage direct current. This is because there have been several HVDC transmission systems that have already proved to be successful in various applications. This includes Basslink, which is a submarine cable connecting Tasmania to Victoria that has a transmission capacity of 500 megawatts. This was established in 2005. Then there is Murraylink that is an underground HVDC link that connects South Australia to Victoria. It has a transmission capacity of 220 megawatts. There is also Terranora Interconnector that connects Queensland to New South Wales. Its transmission capacity is also related to renewable power.

Emerging HVDC projects are expanding Australia’s capacity further. The Australia-Asia PowerLink, a proposed undersea HVDC cable, aims to export solar-generated electricity from Northern Territory to Singapore. Long-distance HVDC proposals are also being studied to connect remote renewable energy zones in Western Australia with eastern states. These developments highlight the growing role of HVDC in enabling Australia’s energy transition. Industry forecasts suggest that Australia’s HVDC market could double in size by 2035, driven by the need for efficient long-distance transmission, renewable energy integration, and grid modernisation.

Challenges and Considerations

While HVDC offers numerous benefits, there are challenges to consider. The capital costs for HVDC infrastructure, including cables, converter stations, and control systems, are substantial. However, these upfront costs are often offset by efficiency gains, reduced transmission losses, and improved renewable energy utilisation over time.

Construction and regulatory approvals can also present obstacles. Large infrastructure projects require careful planning, environmental assessments, and community consultations to minimise impacts, particularly on marine and coastal ecosystems. Integrating HVDC links into the broader electricity grid also demands sophisticated control systems and coordination with regional operators. Ensuring seamless operation between Tasmania and Victoria, especially during extreme weather events or periods of high demand, is critical for realising the full benefits of Marinus Link.

Environmental and Social Impact

Marinus Link offers substantial environmental benefits. By enabling efficient use of hydro and renewable energy, it supports significant reductions in greenhouse gas emissions and reduces reliance on coal-fired generation. This aligns with Australia’s goal of achieving net-zero emissions by 2050.

Socially, the project creates employment opportunities and stimulates economic activity in regional areas. Skilled labour in engineering, electrical works, and project management will be in demand during construction, while ongoing operation and maintenance will provide long-term employment. Additionally, the inclusion of fibre-optic technology enhances communications and data management, supporting the evolution of a smart, interconnected grid.