Overview

Transgrid, as the System Strength Service Provider (SSSP) for NSW, is responsible for ensuring sufficient system strength is available to maintain power system stability in NSW.

In a network without adequate system strength there are inherent stability issues. Generators may be unable to remain connected during disturbances on the power system, control of the system voltage becomes more difficult, and protection systems that ensure safe operation of the network may not operate correctly.

The retirement of NSW’s coal generators and the growth in inverter-based resources in the coming decade is driving an urgent need to add new sources of system strength to the power system.

We have therefore commenced consultation on options to ensure we meet the NER requirements and continue to ensure a safe, secure and reliable power system. We consider that this will enable us to identify the optimal portfolio of solutions to meet both the short-term and long-term needs.

The System Strength Rule Change has established new requirements for connecting parties to meet. A summary of these new requirements can be found on the System strength for network connections page.

Project Assessment Draft Report

The Project Assessment Draft Report (PADR), published in June 2024, provides transparency into the planning considerations for investment options to maintain adequate levels of system strength in the 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 (or portfolio of solutions in this case) has been robustly identified as optimal.

Submissions and Expressions of Interest 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 system strength portfolio options and sensitivities. We have published the PADR and associated supporting documents: 

 Supporting Documentation

A six-week PADR consultation period provides industry with the opportunity to provide feedback on the methodology and outcomes of the PADR. Submissions are due on 2 August 2024.

Non-network option proponent information

Non-network solutions will form a key part of the portfolio of system strength solutions, as identified in the PADR. Transgrid has developed a number of documents to provide further information to non-network proponents to help them better understand the opportunity they have in providing system strength services. These documents are outlined in the table below.

A six-week PADR consultation period provides non-network proponents with the opportunity to submit a new or updated Expression of Interest (EOI) for system strength solutions. EOI submissions are due on 2 August 2024.

Document

Description

Information for system strength non-network option proponents

An explanation of the RIT-T, procurement and contracting process, areas of interest for new EOIs and high-level technical guidance for system strength services

EOI response questionnaire

An Excel workbook that gives proponents the opportunity to update or submit new EOIs

Technical performance and power system modelling requirements for synchronous machines

Detailed technical performance and power system modelling requirements for synchronous machines (for consultation)

Technical performance and power system modelling requirements for grid-forming BESS

Detailed technical performance and power system modelling requirements for grid-forming inverters (for consultation)

Effectiveness Factors

An Excel workbook that indicates the effectiveness of different locations for system strength provision

Industry briefings

In June 2024, Transgrid hosted industry briefings on the outcomes of the System Strength PADR and guidance for non-network proponents. The slides and recordings are available via the following links:

Project Specification Consultation Report

In December 2022 we published a Project Specification Consultation Report (PSCR), the first step in the RIT-T process. The PSCR details the need to meet system strength requirements in NSW and describes credible options to meet the need, including technical characteristics that would be required of a non-network option.

We received submissions from five parties in response to the PSCR, one of which is confidential: Energy Australia, Origin Energy, Smart Wires, Tesla.

Together with the PSCR, we released an Expression of Interest (EOI) to provide additional detail on the technical requirements for non-network options and seek submissions from proponents of these options. In total, 25 companies responded to the EOI to propose over 60 system strength solutions.

RIT-T process and submissions

Transgrid is developing a portfolio of system strength solutions to meet our regulatory obligations and to maximise net benefits to energy consumers. The net benefits delivered by the project are assessed via the Regulatory Investment Test for Transmission (RIT-T) administered by the Australian Energy Regulator (AER). The RIT-T is a formal consultation process designed to:

  • Inform stakeholders of the investment need and proposed options to address it
  • Test the market for alternative and more efficient solutions
  • Explain to stakeholders the basis on which the preferred option has been selected.

The RIT-T consultation process has three stages: