Transpower warns risk of power cuts to parts of north Auckland after large slip

"We are conscious that the people in these regions have been through a lot in recent weeks."
"We are conscious that the people in these regions have been through a lot in recent weeks." Photo credit: Transpower

Transpower is warning of the low risk of potential power outages for parts of north Auckland after a large slip near two electricity towers.

Transpower teams were inspecting the damage caused by Cyclone Gabrielle when they discovered a mammoth slip near two towers carrying high-voltage electricity lines.

The slip, around 10km southwest of Wellsford poses a threat to one tower on the Henderson to Marsden line and another tower on the Henderson to Maungatapere line. 

The landslide is near the point where both lines cross and are closest to the Henderson to Maungatapere line. 

"If it were to move further and bring down the tower on the (Henderson to Maungatapere) line, it could also bring down the [other] line where they cross, cutting off supply from Warkworth north," Transpower general manager grid delivery Mark Ryall said.

Ryall said geotechnical engineers have advised moving the towers instead of trying to stabilise them in place. 

"With more rain forecast, we have removed the (Henderson to Maungatapere) line from service and will lower it to the ground as a precaution."

Ryall said the removal will "mitigate" the risk of both lines being affected at the same time if further land slipped away. 

"We will then relocate the (Henderson to Marsden) line to bypass the tower in the impacted area. This will be an interim step to improve security while we work on a permanent solution."

Ryall said with Warkworth north now being supplied through one tower, that increases the risk of outages in the region if a fault or another weather event hit. 

"We are conscious that the people in these regions have been through a lot in recent weeks," Ryall said.

"While the risk of a fault or further slip on the (Henderson to Marsden) line is small, we wanted to ensure that people are aware of the risk and able to take steps to prepare for any unplanned outages."

He added Transpower is working with local lines companies to manage the possible impact. 

Transpower is urging Warkworth north residents to take precautionary measures in the meantime before the line can be permanently fixed. 

"Such as having an alternative cooking source such as a BBQ with a full gas bottle and ensuring phones and other electrical appliances are charged frequently."

Transpower has found locations for temporary towers to be erected to complete a bypass of the Henderson to Marsden line. 

"Crews are now on site working forming the required access to the area."

But Ryall said gaining access has its challenges. 

"It will take some time to cut a track to be able to bring in the necessary equipment."

He added the first stage of the bypass will be complete by the end of next week.

"We want to assure those in areas impacted that we understand how critical a secure supply of electricity is and we are doing everything that we can to get the bypass in as quickly as possible to mitigate any risk."