Since the major outage in 2015, there have been six smaller outages on Scotland Island and West Pittwater. These have been associated with storm events or vegetation coming into contact with the overhead network. Access and safety issues to both locations have been challenging during these outages, and in turn have contributed to the time taken to restore power.
Ausgrid has completed feasibility and design studies to determine the best solution for each community. We have assessed several options and are moving forward with solutions that aim to minimise the impact of electrical outages to the residents and businesses of Scotland Island and West Pittwater.
Ausgrid has concluded that two different approaches are required for Scotland Island and West Pittwater due to the layout and design of the existing electricity network in each of these areas;
- Scotland Island’s arrangement - a circular network
- West Pittwater’s arrangement - a linear network
A number of project scenarios were assessed for each location including the original cable loop to arrive at the currently proposed solutions.
Current solution for Scotland Island
Ausgrid’s solution uses Horizontal Directional Drilling (HDD) to underbore beneath the ocean bed from Church Point to Richard Road, Scotland Island to install a new electricity cable. Both the new and existing cable will be in service at the same time to minimise the impact of a failure to a single cable. The new cable will lie in a conduit (plastic pipe) below the ocean bed rather than on the ocean floor as the current cable does, which minimises the risk of environmental impact or cable damage.
As part of the design for the HDD bore, Ausgrid is considering future energy requirements for the Island.
A geotechnical study was completed late 2018 at Church Point, Carols Wharf and along the marine cable route.
