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. 

In July 2024, the project was declared Critical State Significant Infrastructure (CSSI). All CSSI applications must be accompanied by an Environmental Impact Statement (EIS). The purpose of an EIS is to identify and assess the potential environmental, economic and social impacts of the project to help government agencies, relevant authorities, community and stakeholders make an informed decision or provide an informed submission on the merits of the project. The EIS will be on public display in late August 2025.

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

Transgrid undertook a voltage study to evaluate the impact of CWOREZ generation on the existing transmission network.​ It was recommended to install transposition structures at select locations on three 500 kV lines between Bayswater, Barigan Creek/Wollar, Mt Piper and Bannaby.​

Transposition in power lines is where lines intentionally cross over or twist the positions of conductors within a transmission line. Transposition is done to reduce the electromagnetic interference, radio frequency interference and ensure the line is more stable.

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.