Central West Orana Renewable Energy Zone Network Upgrades

The NSW government has developed a plan to establish five Renewable Energy Zones (REZs) to increase energy generation, reduce carbon emissions, and help deliver lower wholesale electricity costs to consumers.

The Central-West Orana REZ (CWOREZ), being the first REZ established, is planned to generate at least 4.5 GW by the late-2020s.

Transgrid has been engaged by EnergyCo to undertake upgrades in its existing network to enable increased power flow out of the CWOREZ and ensure the stable, reliable operation of the grid.

The project will strengthen and reinforce the grid in the Hunter, Central Tablelands and Central West regions, helping to ensure that power from the CWOREZ can be reliably transmitted to consumers. 

Click for more information on REZs.

The project will deliver a range of benefits for customers in NSW including: 

• Cheaper electricity – improving the affordability of electricity for consumers by increasing supply and driving down electricity prices  
• Improved reliability – by delivering large amounts of new energy and, strengthening and reinforcing the grid in the local region  
• New local jobs – opportunities for local workers and businesses during construction  
• Reduced emissions and a greater mix of energy in the National Electricity Market.  

What upgrades are Transgrid carrying out?

The scope of works is divided into five projects:

1. New 8km 330kV transmission line between Mount Piper and Wallerawang  
2. New Transposition poles at approximate six locations along three existing 500 kV transmission lines 
3. Modification to the existing 330kV transmission line between Bayswater and Liddell substations 
4. Line cut-in works into the New Barigan Creek 500kV Switching Station. 
5. Substations upgrades at Wollar, Bayswater and Mount Piper. 

The Mount Piper to Wallerawang Transmission Line Upgrade Project comprises of the construction and operation of approximately 8 km of new 330 kV transmission line between the Mount Piper and Wallerawang substations, on the lands of the Wiradjuri people.

The Environmental Impact Statement (EIS) for the Project was on public exhibition between 27 August and 24 September 2025. You can continue to view the EIS at the NSW Department of Planning, Housing and Infrastructure (DPHI).

Further information on this project is located on the project webpage.

The Transposition Project involves installing two approximately 50m high steel poles on each side of the transmission structure, at six locations on private and business properties at Wybong, Merriwa, Monivae, Running Stream, Essington and Paling Yards. Once the poles have been installed, they will be used to change the order of the transmission lines (transposition; see Image 2). 

Additional work will be completed at the Bayswater and Mount Piper substations to put the transmission line back in the order required at the substations.

The benefits to transmission line transposition include:

• Impedance equalisation:
  Transposition helps the electricity to pass through the transmission lines equally which is essential for stability and operation of the electrical grid.
• Voltage balance
  Transposition ensures equal distribution of power through all transmission cables.
• Reducing line losses
  The equal distribution of power in the transmission cables reduces energy losses and improves overall efficiency of the electrical network.
• Electromagnetic interference (EMI) mitigation
  Transposition reduces the size of the electromagnetic field around transmission lines which will reduce impacts from EMI to nearby telecommunication lines.

Landowner engagement and environmental approvals

Engagement with impacted landowners and easement negotiations has commenced and we will continue to work together until the end of construction.

A desktop review and an initial site survey will be undertaken to determine the appropriate assessment pathway. The project will likely be assessed under Part 5 of the Environmental Planning and Assessment Act 1979.

For more information on the Transposition Project, please see the Transposition Factsheet.

The benefits to transmission line transposition include:

• Impedance equalisation:
  Transposition helps the electricity to pass through the transmission lines equally which is essential for stability and operation of the electrical grid.
• Voltage balance
  Transposition ensures equal distribution of power through all transmission cables.
• Reducing line losses
  The equal distribution of power in the transmission cables reduces energy losses and improves overall efficiency of the electrical network.
• Electromagnetic interference (EMI) mitigation
  Transposition reduces the size of the electromagnetic field around transmission lines which will reduce impacts from EMI to nearby telecommunication lines.

Landowner engagement and environmental approvals

Engagement with impacted landowners and easement negotiations has commenced and we will continue to work together until the end of construction.

A desktop review and an initial site survey will be undertaken to determine the appropriate assessment pathway. The project will likely be assessed under Part 5 of the Environmental Planning and Assessment Act 1979.

For more information on the Transposition Project, please see the Transposition Factsheet.

The Bayswater to Liddell project in the Hunter region proposes to modify and upgrade the 330 kV transmission line network between Bayswater Power Station 500/330kV Substation and existing Liddell Power Station 330kV Substation, to enable increased power flows from the CWOREZ to the main load areas, such as Greater Sydney.

Construction is estimated to be completed by 2028.

EnergyCo is building a new switching station at Barigan Creek as part of the CWOREZ. Transgrid will construct 500 kV towers to facilitate cutting-in of Barigan Creek and is proposing upgrades at Transgrid substations located at Wollar, Bayswater and Mount Piper to enable these works.

Community Information Line: 1800 222 537 (free call)
Email: network.solutions@transgrid.com.au

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EnergyCo

If you have questions regarding the development of new transmission lines and substations for the Central-West Orana REZ please visit the EnergyCo website or contact EnergyCo on 0482 061 006 or email cwo@energyco.nsw.gov.au.