Northpower is cautioning households in Whangārei to be prepared for power cuts, given the continuing poor weather and ongoing work to replace a crucial line by the first quarter of this year.

An inspection of Northpower’s Kensington substation and the lines that feed it last winter identified an area of land subsidence near one of the large lattice towers that supports these lines. The tower is on very steep terrain, and given the very wet winter, the Northpower team was concerned that subsidence may indicate that the ground in the area was unstable and that the tower may be at risk.

The substation and lines provide a critical link between Transpower’s national grid and the distribution networks that feed into central Whangārei and the surrounding suburbs.

Specialist inspection and monitoring of the subsidence by Northpower’s geotechnical consultants confirmed subsidence was an indicator of a longer-term issue.

Their work concluded the foundations of the tower were likely to be undermined at some point, and if this were to occur, extensive damage to the line and extended power outages for the region could result.

Northpower chief operating officer Josie Boyd said teams have been working tirelessly to engineer a solution that would remove dependency on the impacted tower. The first stage of these works involves the construction of two temporary bypass lines around the impacted tower; stage two will involve re-engineering of the existing line to avoid the impacted area.

Before Christmas, the construction of the first of these bypass lines was completed. Boyd said this had been a major undertaking due to the scale of the lines involved, the very steep terrain, and the ongoing wet weather during the construction of the line.

Power is now flowing through the new line, and the impacted tower has been removed from service.

“A fault on the new line would still result in a power outage, while repairs were [being] made – in a worst-case scenario, we could still see power out for around 8000 customers for several days.”

She said completion of the second bypass would reduce that time to a few minutes, and completion was scheduled for the end of March.

“Given the continuing outlook of poor weather over the summer, Northpower wants our community to be aware that there is an elevated risk of outages during this time while we rely on a single line. This is a good reminder for people to be prepared and think about their contingency plans should something unexpected happen.

“It is a good idea to always be prepared for an unexpected power outage. Keeping a full gas bottle for the barbecue, alternative forms of lighting in a handy place with batteries and your devices charged are practical steps we can all take.”

Boyd said Northpower would update the community when the second line has been constructed, and if there were any concerns, people should contact its customer centre on 0800 667 847.