by Ralf Riccardi, Project EnergyConnect Project Director, ElectraNet

Australia’s energy landscape is changing, with renewable electricity sources displacing traditional generation. Renewable energy sources have become the largest source of generation in South Australia, with more than 60 per cent of the state’s annual electricity demand met by these sources. Transmission projects like Project EnergyConnect will be integral to the successful transition of power systems.

As South Australia continues its uptake of renewable energy, the state’s transmission network is playing an increasing role in managing two-way power flows and sharing power between regions to where and when it is needed. Project EnergyConnect, the new high-voltage interconnector between South Australia and New South Wales, is a central feature of the roadmap for the transition of the power system developed by the Australian Energy Market Operator (AEMO) in its 2020 Integrated System Plan (ISP).

The South Australian component of the project is being delivered by ElectraNet, the owner and operator of South Australia’s electricity transmission network and the New South Wales component is being delivered by TransGrid. The primary purpose of the new interconnector is to enhance system security, provide net market benefits and support the transition of the energy market to a lower carbon emissions future.

The infrastructure

Project EnergyConnect involves the construction of a new 900km, 330kV transmission line connecting Robertstown in South Australia to Wagga Wagga in New South Wales, with an added connection to Red Cliffs in Northwest Victoria.

The South Australian component includes a new 200km double circuit line in both 330kV and 275kV from Robertstown to the South Australia/New South Wales border; a new 275–330kV substation at Bundey; additional substation and line works to connect into the existing transmission network; and a new Special Protection Scheme and associated studies, commissioning and testing.

The progress

The project’s first transmission pole was installed at the Robertstown substation, about 130km north of Adelaide, in February 2022. Stage 1 of the project will be complete by the end of 2023.

ElectraNet developed a project-specific commercial strategy and framework to ensure it provided the best outcomes for the project and power customers.

The strategy featured extensive industry engagement, incorporating both domestic and international contractors considered experienced and capable of performing the scope of works required.

The strategy and engagement have resulted in:

» An optimised concept design and delivery methodology
» Efficient project delivery as designs evolved from initial concepts to detailed design Improved risk allocation and management, with project risks residing with the party best able to efficiently manage them
» An efficient project schedule optimised to ensure the best project outcomes

ElectraNet is delivering the South Australian component of Project EnergyConnect, which includes a new 200km double circuit line, additional substations, and a new Special Protection Scheme.

The objective

The objective of Project EnergyConnect is to improve the affordability, reliability and sustainability of electricity supply in the National Electricity Market (NEM) through increased electricity transmission between South Australia, New South Wales and Victoria.

The aim is to create a net benefit to consumers and producers of electricity, and support the transition of the energy market to a lower carbon economy using the following means:

» Enhancing security of electricity supply in South Australia by providing a second major interconnector to the rest of the NEM
» Increasing electricity supply competition and trade by improving network access and capacity, thereby reducing wholesale electricity costs using market means
» Providing new opportunities for renewable energy and other energy projects to connect to the NEM, thereby stimulating economic activity and facilitating transition to a low carbon economy

It is expected that the achievement of these objectives will provide a wide range of benefits at a local, state and national level.

The challenges

As with any project of this size, there have been several key challenges so far, with the task of selecting the most appropriate contractor a majority priority.

It was predicted that the energy system in Australia was going to transition over the next 10–15 years, placing considerable demand on key skills, labour and material supplies. Labour and skill shortages were predicted to become a significant factor for transmission infrastructure with shortages and constraints predicted for line workers, electricians, construction managers, electrical and civil engineers.

It was also expected to significantly increase consumption of steel and concrete. The project found itself in a market with significant competition for these resources.

ElectraNet developed a commercial strategy and framework for the specific purpose of delivering the project while ensuring best for project, best for customer outcomes. The strategy has facilitated extensive industry engagement, incorporating both domestic and international contractors considered experienced and capable of performing the required scope of works.

The next key challenge will arise once the assets are built and connected between the states. The final phase of the project will be the integration of the interconnector into the NEM. This will provide significant challenges with system integration activities including the preparation and implementation of a test plan to allow the transfer of capacity to be safely and reliably increased between the states up to its maximum.

The maintenance

The design life of the new transmission line, with appropriate maintenance, is approximately 100 years and during standard operation, the transmission line will require minimal ongoing maintenance.

Inspection and maintenance activities are predominantly carried out by light 4WD vehicles. The maintenance program typically involves ground inspections every three years for signs of unusual wear, structural integrity and corrosion or damage. Helicopterbased inspections are undertaken annually.

The future

New interconnector projects like Project EnergyConnect play a critical role in supporting the transition to a low carbon economy. Many of Australia’s networks are aging and require important and required investment to facilitate this transition.

In South Australia, transmission network costs are about ten per cent of a ‘typical’ residential customer power bill. The state has one of the oldest transmission networks in the country and timely investment in new transmission infrastructure is needed in order to transition to a renewable energy grid.

Infrastructure investment in projects such as this will enable the power generated in renewable energy zones, which are normally located in remote parts of Australia, to be transmitted to cities and towns. It will also enable households to connect more solar, batteries and electric vehicles to the grid.

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