Working with hapū to strengthen network resilience
Location: Pukenui Ngahere, Western Hills, Whangārei
Investment: $3.06 million
Start Date: October 2022
Completion Date: August 2024
Project partners: Te Parawhau, Clements Quarry, Edison Consulting Group, Lumen, Ecology North
Swift action to secure our infrastructure
A routine inspection of high voltage lines between the Maungatapere and Kensington substations identified an area of land subsidence near one of the large support towers – Tower 29.
Our team were concerned that subsidence may indicate unstable ground, potentially risking the tower and it’s supported lines. Specialist inspection and monitoring of the subsidence by Northpower’s geotechnical consultants confirmed this was the case.
This prompted an immediate response from our team to devise a solution to tackle potential future supply disruption caused by subsidence.
5018
person-hours invested
19
personnel onsite at peak work times
40m
monopole installed
Building a temporary backup to prevent outages
To mitigate the risk of potential land slippage, two temporary transmission towers were created as a bypass, situated to the east and west of Tower 29.
If one temporary tower were to fall, the other would still provide electricity supply to Whangārei. Sourcing transmission poles takes six months, so the team improvised by constructing the bypass line using distribution poles.
Our network team provided technical expertise in collaboration with Edison Consulting Group to project manage, and engineering design experts Lumen.
Delivering a lasting fix to safeguard our network
The two-year lifespan of the temporary towers required the design and construction of a new permanent line, including sourcing a new 40m monopole to support a new 110kV conductor. A suitable site for Tower 29A was selected in the forest area adjacent to Clements Quarry, known to Te Parawhau as Pukenui Ngahere.
Construction works commenced in April 2024 and were completed over a four-month construction period by Northpower’s Hamilton based transmission crews.
In July 2024, the staged transfer of a conductor to the new section of the 110kV transmission line was completed.
Timelapse of monopole installation
Partnering with hapū to honour kaitiakitanga
As kaitiaki of Pukenui Ngahere, Te Parawhau played a key role throughout this project. Their significant input through a Te Ao Māori approach resulted in a construction process upholding kaitiakitanga, and a supply solution with minimal impact on the taonga species in the forest.
Throughout the project, important cultural protocols were followed. Early on, a mihi whakatau and hui was held with our executive, signifying the importance of the partnership between Northpower and Te Parawhau. Dialogue flowed between the project team and hapū – listening to each other during every step of the project – and providing and receiving valuable feedback on the possible designs resulted in a solution to best meet the needs of all involved.
To conclude the project, Te Parawhau blessed the site and gifted Tower 29A the name of ‘Toitū Te Hihiri’ – translated as ‘to hold up the life energy that flows through us’.
An award-winning approach
This project team was awarded the Engineering Excellence award at the 2024 Electricity Engineers’ Association of New Zealand awards, for their outstanding engineering and technical delivery, their collaboration with hapū and the integration of Te Ao Māori principles.
Keeping the power on for Whangārei
The successful delivery of the project ahead of schedule is a testament to Northpower’s capability to scale up and deliver innovative, culturally appropriate solutions quickly to serve the needs of our people.
Our Whangārei network now has improved resilience so we can continue to provide our local communities and economy with the secure electricity supply they need to grow.
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