Wairoa submarine cable crossing
Location: Raupo, Ruawai to Tikinui, Pouto
Investment: $1.6 million
Start Date: June 2024
Completion Date: December 2024
Project partners: Nexans, Protectorshell, Seaworks, Te Uri O Hau, Atlas Cranes, Solid Civil Solutions
Improving network reliability in Kaipara
We maintain our assets to ensure the reliability of supply to customers across Whangārei and Kaipara. As part of this year’s network investment plan our team completed work installing two new submarine cables across the Wairoa River between Raupo, Ruawai and Tikinui on the Pouto Peninsula during November 2024.
The original two submarine cables were installed 50 years ago and these end-of-life assets were due for replacement. This upgrade delivers increased security of electricity supply to one of the most remote parts of our network, the Pouto Peninsula on the West Coast of the Kaipara Region.
1883
person-hours invested
$1.6m
invested
16
Northpower personnel onsite
Surveying the site and working with iwi
Extensive planning, including riverbed surveys for tides and flow, determined the best method for installing the cables before the project started.
We worked closely with local iwi Te Uri O Hau from the early stages of the project. For them, the riverbed is a taonga (treasure). They advised on the archaeological and environmental aspects of the project to ensure the project delivery and solution was culturally appropriate.
Overview with Ben Bulling, Project Manager
Installing the cables
In late November, the river was closed to boats for submarine cable installation. Locals were notified through well placed signage, social media, Seaworks, the Harbourmaster, and letters were distributed to local residents.
The installation, which was scheduled to take place over a three day period, used a variety of heavy machinery and the skills of specialist divers. The new cables being installed were tied to buoys which were guided across the river using a winch to pull and a cable engine to push.
Once the cables were in place across the river, divers cut the ropes tying the cables to the buoys, allowing the cables to sink and settle into place on the riverbed. Cast iron protector shells were also installed to protect the cable and to help prevent damage caused in the event of boat strike or accidental contact.
The cables were commissioned in mid-December. The ground mount switch and 50kVA transformer were installed at Tikinui to connect the cables to the network. Redundant overhead lines from Pouto Road to Tikinui Slip Road were removed.
Coordination and teamwork
This project required detailed coordination between many contractors, including our network team and our energy services delivery team, Seaworks (who specialise in installing marine cables), Solid Civil Solutions, TMNZ, and Atlas Cranes.
A total of 1,883 person-hours ensured the smooth delivery of the project – from the early planning, design and engineering stages to the installation of distribution assets on either side of the river and supporting Seaworks to install the new cables.
The replacement of these cables ensures that the Pouto Peninsula will have a more secure supply for decades to come.
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