TransGrid PSCR: Managing safety and environmental risks on Line 21 (Tuggerah – Sydney North)

Market Network Service Provider
StageProject Specification Consultation Report
ConvenorAEMO NSP
Accepting submissions?No
Submissions close19/10/2021

TransGrid has recently published a Project Specification Consultation Report (PSCR) for managing safety and environmental risks on Line 21 (Tuggerah – Sydney North). 

Spanning a route of 65 km, Line 21 is a 330 kV transmission line that runs between Tuggerah and Sydney North substations. It was originally built in 1959 as part of a double circuit 132 kV line from Sydney North to Dora Creek, but was upgraded to single circuit 330 kV and turned in to Munmorah in 1962, and a tee to Tuggerah added in 1986 at Sterland. This RIT-T is being undertaken to address environmental and safety risks on a portion of this original section of Line 21 – between the Tuggerah cut-in and Sydney North substation. This section of the line is comprised of 113 steel towers and spans approximately 51 km.

Line 21 is a key link between the Central Coast and Sydney metropolitan area and will continue to play a central role in supporting the flow of energy to take advantage of naturally-diverse weather patterns, and in the safe and reliable operation of the power system throughout and after the transition to a low-carbon electricity future.

Condition issues that will impact the safe and reliable operation of the network have been found on Line 21. The condition issues raise a number of risks associated with asset failure, including safety and environmental (bushfire) risks. Investment to address the deterioration of the assets along Line 21 due to corrosion is needed to mitigate risks to safety and the environment.

TransGrid manages and mitigates bushfire and safety risks to ensure they are below tolerance levels or ‘As Low As Reasonably Practicable’ (‘ALARP’), in accordance with TransGrid’s obligations under the New South Wales Electricity Supply (Safety and Network Management) Regulation 2014 and TransGrid’s Electricity Network Safety Management System (ENSMS). The proposed investment will enable TransGrid to continue to manage and operate this part of the network to a safety and risk mitigation level of ALARP. Consequently, it is considered a reliability corrective action under the RIT-T.

In the PSCR TransGrid presented one credible network option that would meet the identified need from a technical, commercial, and project delivery perspective. Two other options to address the need were considered but were not progressed due to technical and commercial feasibility. The optimal commercially and technically feasible option presented in this PSCR – Option 1 (line refurbishment) – is the preferred option to meet the identified need. 

The estimated capital cost of this option is approximately $19.6 million +/- 25 per cent. TransGrid is the proponent of the proposed network project.

TransGrid welcomes written submissions on materials contained in this PSCR. Submissions are particularly sought on the credible options presented and from potential proponents of non-network options that could meet the technical requirements set out in this PSCR. Submissions are due on 19 October 2021.

In accordance with the requirements of the National Electricity Rules, a summary of the PSCR is made available on the AEMO website. A copy of the PSCR can be obtained from TransGrid’s website or by emailing

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