North West Slopes Area Supply

The latest forecasts indicate that electricity demand is expected to increase substantially in the North West Slopes area going forward. This is mainly due to a number of substantial industrial loads that are anticipated to connect, as well as underlying general load growth in Narrabri and Gunnedah.

Transgrid is applying the Regulatory Investment Test for Transmission (RIT-T) to options for maintaining reliable supply in the North West Slopes area in Northern NSW. This would involve new infrastructure to address load growth in the area.

A grid-scale battery has been identified as part of the preferred option for maintaining a reliable supply of electricity to the North West Slopes region.

Transgrid is seeking services from a BESS to be installed in the Narrabri or Gunnedah region (potentially paired with other supporting technologies), which will provide both active power and reactive support to manage thermal and voltage constraints on Transgrid’s network during peak demand periods, from 2025 or soon thereafter. This will enable Transgrid to maintain secure and reliable supplies to customers in the region, even in the event of a fault or outage. 

Transgrid is now entering a competitive procurement process to buy services from this new battery project, before finalising contracts with the successful proponent. 

We will hold an online Market Forum to brief potential suppliers on August 10 at 10:00am (Australian Eastern Standard Time). We invite all interested parties to attend to hear more about this opportunity. 

For participation in the Market Forum, please sign up by completing the online form available here.

Parties wishing to participate in the competitive process and access the RFT will need to separately register. Please contact us at BOP_NWS@transgrid.com.au for further details and information and eligibility requirements.

We intend to release the full Request for Tender (RFT) package to registered participant later in August, with responses due back after around 8 weeks.

Transgrid must show that the preferred option for maintaining reliable supply in the North West Slopes area will deliver the greatest net benefits to energy consumers. The net benefits delivered by the project are assessed using the Regulatory Investment Test for Transmission (RIT-T) administered by the Australian Energy Regulator (AER).

The RIT-T assesses network and non-network solution options from a technical and economic perspective by:

• Informing stakeholders of the investment need and proposed options to address this need
• Testing the market for alternative and more efficient solutions
• Explaining to stakeholders the basis on which the preferred option has been selected.

We have now completed the final stage of the RIT-T and after assessing multiple options, identified that options involving non-network solutions coupled with network upgrades are preferred over solely network options.

Project Specification Consultation Report

In April 2021 we published a Project Specification Consultation Report (PSCR), the first step in the RIT-T process.

The PSCR detailed the need to maintain reliable supply in the North West Slopes area and describes credible options to meet the need, including technical characteristics that would be required of a non-network option.

We did not receive any submissions directly to the PSCR, however two parties responded to an Expression of Interest which was published alongside the PSCR to explore possible non-network solutions that could meet or assist with meeting the Identified Need.

Both parties requested confidentiality, therefore we have not reproduced any of their material in the PADR or on our website.

Project Assessment Draft Report

The Project Assessment Draft Report (PADR) , published in February 2022, provides transparency into the planning considerations for investment options to stabilise the Northern NSW power system, and the associated market benefits. A key purpose of this PADR, and the RIT-T more broadly, is to provide interested stakeholders the opportunity to review the analysis and assumptions, provide input to the process, and have certainty and confidence that the preferred option has been robustly identified as optimal.

Submissions received in response to the PSCR were considered when preparing the PADR.  The PADR includes a full quantitative analysis of the proposed options and expected net market benefit across a range of scenarios and sensitivities. We have published the following supporting documents: 

We invited written submissions on the material contained in the PADR. We received submissions from eight parties in response to the PADR, five of which are confidential. Submissions approved for publication are from:

• Public Interest Advocacy Centre
• Whitehaven Coal – Narrabri Coal
• Whitehaven Coal – Vickery Coal

We engaged further with parties to confirm the status and technical feasibility of the options, which involved the provision of further information from these parties.

Thank you to those who made a submission throughout the RIT-T process.

Project Assessment Conclusions Report

In June 2022, we have published the Project Assessment Conclusions Report (PACR) for maintaining reliable supply to the North West Slopes area.

The PACR has been prepared as the final step in the Regulatory Investment Test for Transmission (RIT-T) process and follows the Project Assessment Draft Report (PADR) published in February 2022.

The assessment in this PACR finds that a non-network solution provided through a Battery Energy Storage System (BESS) at the Gunnedah 132 kV substation and the installation of a third transformer at Narrabri 132 kV substation in the near-term, along with upgrades to existing transmission lines in the longer term, is the preferred option for meeting the identified need.

PACR Supporting Documents

• EY Market Modelling Report 
• NPV Model Outcomes 

Amended Project Assessment Conclusions Report

In January 2023, we have published an amended PACR for maintaining reliable supply to the North West Slopes area.

The release of this amended PACR follows the AER's decision on a dispute notice from the Public Interest Advocacy Centre (PIAC) on the initial PACR. This amended PACR therefore updates the assessment and PACR in-line with the AER dispute determination.

The preferred option identified in this amended PACR remains unchanged from the initial PACR.

Amended PACR Supporting Documents

• Amended PACR NPV Model Outcomes
• GHD Independent Demand Forecast Review

We will now enter into a competitive procurement process and commercial negotiations with non-network proponents for a network support service and seek to put in place a contract with one of these parties.

If you have any questions about the project, please contact community@transgrid.com.au or phone 1800 222 537.