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Options assessment method

VicGrid developed a decision-making tool, the options assessment method, for assessing potential transmission corridor and technical options to balance competing priorities and ensure community and stakeholder feedback informed the approach.

The assessment method was used to narrow a long list of corridors and technical options to a preferred corridor option and technology. You can find more information about the assessment process in the Gippsland Options Assessment Report.

Identifying a study area

VicGrid used the preferred corridor option to create a broader study area. This is because assessments so far have been based on available desktop information.

Further technical studies, on-the-ground environmental assessments and engagement with landholders, farmers and local communities are now needed to refine and narrow the study area to a corridor (and then a route).

Reducing the study area to a corridor aims to remove land that is less suitable to host transmission infrastructure.

Identifying a preferred technology

We investigated multiple combinations of technologies, including fully undergrounding the transmission line.

The options assessment method was used to undertake a high-level analysis and identify key points of differences between options.

While undergrounding is technically feasible, it was ruled out as an option after careful analysis due to challenges including cost, engineering complexity, procurement, and timing.

After careful consideration of the merits and complexities of 330 kilovolt (kV) and 500 kV transmission technology, we decided a 500 kV transmission line is the most suitable solution for this project.

500 kV transmission has a higher transfer capacity than 330 kV transmission technology and will result in around half the power loss of 330 kV transmission. Power losses happen when electricity is transported across a network, and higher power losses increase costs for consumers.

To achieve future offshore wind energy targets of up to 9 gigawatt (GW), the 500 kV solution would require only a single set of towers per corridor. The 330 kV solution would require two sets of shorter towers, which would have a higher visual amenity impact.

We heard landholders and the community want to know the long-term cost comparison of underground and overhead, asking how and why the project cost is passed on to consumers.

To deliver affordable energy, VicGrid must balance complex factors and make decisions that are in the best interests of all Victorians. This is why we consider cost in our decision-making, to keep down impacts on power bills.

Our analysis found that an overhead line would cost between approximately $700 million and $1.5 billion, while undergrounding would cost between approximately $2 billion and $4.5 billion. The extra expense is largely due to the additional infrastructure construction costs required.

Those additional costs would be paid for by all Victorian homes and businesses through higher power bills.

Refining the study area

VicGrid has completed desktop analysis and applied the refinement criteria to identify and assess areas suitable for further investigation to host transmission for the first 2 GW of offshore wind.

Using our refinement criteria and VicGrid’s guiding principles, our desktop refinement work so far has identified:

  • areas that are not suitable for further investigation and have been removed from the study area
  • areas suitable for further investigation to host transmission infrastructure.

Some areas have been identified as not suitable to host transmission for a range of reasons, including presence of highly sensitive protected species, technical constructability or feasibility.

You can read more about our work so far to refine the study area in the refinement factsheet.

We are working with landholders in the study area to help understand important areas and features in the study area.

Page last updated: 12/12/24