Victoria launches Marinus Link converter station, minister dismisses gas and nuclear plans

Victoria’s new energy minister, Jaclyn Symes, has officially opened the Marinus Link converter station. Symes recently replaced Lily D’Ambrosio in the role. During the launch event, she addressed recent political debates regarding future energy infrastructure.

According to RenewEconomy, Symes dismissed Opposition proposals to expand gas and nuclear power in the state. She characterized these plans as a "fantasy," signaling a firm government stance against shifting away from renewable energy targets. The minister’s comments highlight the ongoing political tension over Victoria’s long-term energy strategy.

The opening of the converter station marks a key milestone for the inter-state transmission project. While the facility is now operational, broader discussions on energy mix remain active in parliament. Symes’s remarks underscore the current administration’s commitment to existing renewable frameworks.

Infrastructure Launch

Groundbreaking work has commenced on the Marinus Link converter station in the Latrobe Valley, marking the physical arrival of this major inter-state transmission initiative. The facility serves as the critical terrestrial anchor for the project, which links Victoria’s electrical grid to Tasmania through an undersea cable. By establishing this connection, the infrastructure facilitates the movement of electricity between the two states, allowing surplus generation in one region to support demand in the other. This type of interconnection is essential for grid stability, as it enables operators to balance supply and demand fluctuations across a wider geographical area rather than relying solely on local generation.

The location in the Latrobe Valley is significant for the broader energy transition, as the region historically hosted coal-fired power stations. Repurposing land in such areas for new renewable infrastructure helps integrate modern transmission assets into existing electrical networks, potentially reducing the need for extensive new land clearing. For grid operators, these converter stations are vital for managing the flow of alternating current, ensuring that power transmitted over long distances remains stable and compatible with local distribution systems. The start of construction signals a shift from planning phases to tangible asset delivery, moving the project closer to its eventual operational capacity.

Technical Specifications

• One 750 MW cable constitutes the first stage of the project
• Hitachi supplies grid-forming technology for the converter stations
• Hazelwood North and Heybridge serve as the two converter station locations
• Each station houses four 330-tonne transformers and 24 valve structures
• Valve structures stand 11 metres tall

The physical scale of the Marinus Link infrastructure is defined by its dual-site layout at Hazelwood North and Heybridge. These locations anchor the system, each housing four massive 330-tonne transformers alongside 24 valve structures that rise 11 metres high. Such height is necessary to manage the high-voltage direct current conversion process, where electrical energy is transformed for efficient long-distance transmission. The sheer weight of the transformers underscores the industrial magnitude required to handle the power flows between the two states, demanding robust civil engineering foundations to support the heavy equipment.

Hitachi provides the grid-forming technology that enables these stations to stabilize the connected networks. Unlike conventional inverters that follow the existing grid frequency, grid-forming systems can establish and maintain voltage and frequency independently. This capability is vital for integrating high levels of renewable energy, which often lacks the inherent inertia of traditional synchronous generators. By supplying this advanced technology, the project ensures that the 750 MW cable in the first stage can operate reliably, supporting the broader stability of the inter-state connection without relying on legacy thermal plant characteristics.

Cost and Context

The financial trajectory of the Marinus Link project has seen a substantial shift, with total costs rising from an initial estimate of $1.3 billion to over $3.5 billion. Such significant cost escalations in large-scale transmission infrastructure often reflect evolving material prices, complex engineering challenges, or regulatory requirements that emerge during the construction phase. For investors and state governments, these figures highlight the capital intensity of modern grid upgrades. While the initial budget may have been based on early-stage planning, the final cost incorporates the realities of executing a project of this magnitude, including the installation of heavy-duty equipment and the management of inter-state coordination. This increase underscores the economic weight of securing reliable, high-capacity transmission links, which are increasingly viewed as essential assets for a renewable-heavy energy system.

Beyond the financial scope, the project holds a distinct technical distinction within the national grid. Marinus Link is the first Australian interconnector to utilize grid-forming technology at both ends. This architectural choice differentiates it from many existing links that rely on conventional inverter-based systems. By employing this technology at both the Victorian and Tasmanian terminals, the system can actively support voltage and frequency stability rather than merely following the grid. Andrew Train, the project director, oversees this implementation, ensuring that the technical specifications meet the operational demands of connecting two separate electrical networks. This dual-end application is a notable departure from standard practice, offering a new benchmark for how future inter-state connections might be designed to handle the variability of renewable energy sources. The decision to prioritize this technology reflects a strategic move to enhance grid resilience without relying on traditional thermal plant inertia.

What to watch

With the converter stations now under construction, attention shifts to the physical integration of these heavy assets with the existing Latrobe Valley grid. The next critical milestone involves the successful commissioning of the 750 MW cable, a process that requires precise synchronization between the Victorian and Tasmanian networks. Readers should monitor the timeline for the first stage’s operational handover, as this marks the transition from civil works to live electrical testing. Any delays in this phase can ripple through the broader project schedule, affecting the availability of the inter-state link for peak demand periods.

Beyond the immediate construction, the long-term performance of the grid-forming technology will be a key indicator of the system’s resilience. As renewable penetration increases, the ability of the converter stations to maintain voltage and frequency stability without thermal plant support will be tested under real-world conditions. Stakeholders should also track regulatory developments regarding inter-state electricity trading rules, which determine how surplus power moves between the two states. The success of this initial stage will likely inform design standards for future interconnectors, offering practical insights into managing high-voltage direct current systems in a renewable-heavy grid.