TransGrid has recently published a Project Assessment Conclusions Report for Managing the Risk of Corrosion between Marulan and Dapto on Line 8.
Constructed in 1956 and 1962, Line 8 is a single circuit steel tower 330 kV transmission line connecting Marulan and Dapto 330 kV substations. The 70 km long transmission line traverses farmland, national park areas, and climbs from the coastal plain up the Illawarra Escarpment.
A significant proportion of the 175 transmission structures of Line 8 are corroded, including steel towers, insulators, conductor fittings and conductor/earth wire. Corrosion greatly increases the likelihood of conductor drop and presents consequent bushfire risks and safety risks.
In September 2018 TransGrid published a Project Specification Consultation Report (PSCR) identifying the proposed preferred option to mitigate the risks and claimed exemption from producing a Project Assessment Draft Report as allowed for under NER Clause 5.16.4(z1).
No submissions were received in response to the PSCR during the consultation period which closed in December 2018. No additional credible options that could deliver a material economic benefit were identified throughout the process and the outcomes of the economic analysis contained in the PSCR remain unchanged and maintained in this PACR.
The PACR recommends the replacing or refurbishing corroded components from 2018/19 to 2020/21. The estimated capital cost of the proposed preferred option is $6.1 million. TransGrid is the proponent of the proposed network project.
In accordance with the requirements of the Rules, a summary of the PACR has been made available on AEMO’s website. A copy of the Project Specification Consultation Report can also be obtained from TransGrid’s RIT-T Consultations webpage or by emailing RIT-TConsultations@transgrid.com.au.