Mount Piper to Wallerawang Transmission Line Upgrade Project

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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 330 kV substations, on the lands of the Wiradjuri people. 

The Project will strengthen and reinforce the grid in the State’s Central Tablelands region, helping to ensure that power from the Central-West Orana Renewable Energy Zone (CWOREZ) can be reliably transmitted to consumers. 

If approved, the project will deliver a range of benefits 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
• Reduced emissions and a greater mix of renewable energy in the National Electricity Market
• New local jobs – opportunities for local workers and businesses during construction

Environmental Impact Statement

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).

The EIS is a detailed technical document that assesses the potential environmental impacts of the proposed project and outlines the measures and mitigations to be implemented in the region where it would be constructed.

Response to Submissions Report and Amendment Report

Transgrid has reviewed the submissions made during the EIS Public Exhibition period and developed a Response to Submissions Report, that collated, categorised and responded to submissions received from community members and groups, councils and government agencies.

A number of proposed project amendments and refinements were identified in response to issues raised in submissions received on the EIS, as well as in response to ongoing design development and construction planning. The amendments and refinements provide improvements to the design and construction methodology. These were assessed and reported in an Amendment Report. 

View the reports

EIS factsheets

The EIS fact sheets provide a summary of key technical studies, the methodology we used to identify and assess potential project impacts, our findings and how we propose to manage or minimise them. 

Transgrid listened to feedback from community and stakeholders in identifying and assessing routes for this project and are grateful for feedback provided. Following Transgrid’s route selection process, community input and assessment of route options, we have identified a preferred route.

The preferred route minimises visual impact for community and the local township and balances landowner preferences and various constraints including engineering, constructability, environmental impacts and cost, to ensure that the outcome is prudent and efficient. The report can be accessed in the resources section on this page.

Transgrid recognises the vital role that stakeholders, landowners and the community have in the planning and delivery of its projects. We are committed to engaging with stakeholders to understand what’s important and work out the best possible solution.

Critical State Significant Infrastructure

On 3 July 2024, the Mount Piper to Wallerawang Transmission Line Upgrade Project was declared Critical State Significant Infrastructure (CSSI). CSSI projects are declared when a project is essential for NSW for economic, environmental and social reasons. All CSSI project applications must be accompanied by an Environmental Impact Statement (EIS).

Environment Protection and Biodiversity Conservation

Transgrid submitted a referral under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The EPBC Act is Australia’s main environmental law and provides a legal framework to protect matters of National Environmental Significance. The project has been decided as a ‘controlled action’ and will need Commonwealth approval. You can view the referral on the Department of Climate Change, Energy, the Environment and Water’s (DCCEEW) website by searching for EPBC Number 2024/09855.