Transgrid has recently published a Project Assessment Draft Report (PADR) for managing risk on Line 86 (Tamworth to Armidale) in Northern NSW.
Given the increasing rate of defect issues on Line 86’s wooden poles, Transgrid considers it is likely that all the structures on Line 86 are exhibiting various forms of decay, which is only expected to worsen over time. In addressing the condition issues on Line 86, an opportunity exists to provide extra capacity in this region of our network and, in doing so, address potential future constraints in the network and facilitate conditions that enable market benefits to be derived, associated with new generation and storage within the National Electricity Market.
The Project Specification Consultation Report (PSCR) was released in December 2021. Transgrid subsequently received submissions from three parties.
The credible options considered in the PADR assessment have been refined since the PSCR, to reflect:
submissions to the PSCR, in particular consideration of a Virtual Transmission Line (VTL) coupled with a network option; and
the outcomes of detailed market modelling and reviewing updated data on both the condition and risk of each wood pole on Line 86.
The results of the PADR assessment find that a focused replacement of the highest risk Line 86 wood poles, like for like and in-situ with concrete or steel poles is the preferred option for meeting the identified need. The PADR assessment shows that the additional costs of replacing Line 86 with either a higher capacity line or in combination with a VTL are not outweighed by the additional wholesale market benefits expected.
Transgrid welcomes written submissions on this PADR. Submissions are due on 15 July 2022.