Two 11,000-volt submarine cables currently supply Scotland Island and the West Pittwater residents and businesses. Ausgrid is implementing measures to improve energy security to the area following extended power outages in December 2013 and February 2015.
The installation of a backup electricity cable to Scotland Island is in the final stages of design with construction planned to start in early 2020. The work is expected to take four to five months to complete.
The new cable will be housed in a conduit (plastic pipe) installed using a horizontal directional drill (HDD) to bore under the waterway between Church Point Reserve Carpark and Richard Road on Scotland Island.
Two additional conduits will also be installed for future cables and space will be provided for fibre which may be used for the NBN rollout to the Island. A switching system will also be installed so we can isolate faults in the overhead network, as required. This will mean we can restrict power outages to a smaller number of residents whilst the problem is being resolved.
In the event of an overhead outage, the existing submarine cable will supply power to the western side of the Island, and the new cable will supply the eastern side. This will allow for a much quicker restoration of power to the half of the island which does not have an issue on its overhead network.
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 overhead networks and have not been related to the submarine power cables. Access and safety issues to both locations have been challenging during these outages, and in turn have contributed to the time taken to restore electrical power.
Ausgrid has completed feasibility and design studies and continues to with industry experts to determine the best solution for each community. We have assessed a number of 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.
Ausgrid’s proposed 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 in order 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 and the possibility of including NBN and other communication cables or fibres.
A geotechnical study was completed late 2018 at Church Point, Carol’s Wharf and along the marine cable route.
Under the Environmental Planning and Assessment Act 1979, Ausgrid is the determining authority for this project.
An environmental assessment will be prepared on the works in accordance with Part 5 of the Environmental Planning and Assessment Act 1979 and Clause 228 of the Environmental Planning and Assessment Regulation 2000.
Community feedback has been sought at various stages since 2017, to assist the project team better understand the needs of the community.
We have been keeping the community informed throughout the course of this project. Community feedback has been an integral aspect in our analyses and our decision-making processes. It has allowed for the Scotland Island community to understand why we have reached the outcomes we have so far. Ausgrid will continue to work together with the Scotland Island community.
Ausgrid has met with key stakeholders including Northern Beaches Council, Rural Fire Services, National Parks and Wildlife, local Members of Parliament (State and Federal) and community group representatives to collect feedback and provide project updates.
Community feedback (including survey responses) has assisted Ausgrid to confirm the proposed solutions for Scotland Island and West Pittwater. A summary of the initial community feedback received and how it has been considered can be viewed via the PDF link at the bottom of this page.
Should you require more project information, or would like to provide feedback to us, please do not hesitate to get in touch via: