Finishing lines project early a ‘milestone’

Transpower's Clutha-Upper Waitaki lines project to almost double its northward transmission capacity has been completed ahead of schedule.

Project director Roy Noble said the commissioning of the duplexing project between Roxburgh and Livingstone this week, ahead of the company’s May target date, was a "significant milestone" for the company.

"[It] represents an enormous amount of work by our line and substation crews. At its peak, the project had more than 140 crew members, most of whom were away from their homes and families, working long hours in challenging conditions," Mr Noble said.

"Completing the project ahead of schedule, and safely, is a testament to the dedication of our service providers and wider project team."

Livingstone is 30km northwest of Oamaru.

The work was part of Transpower’s upgrade of the national grid between Roxburgh and Livingstone, on the Roxburgh to Islington 220kV line.

The $100 million project involved a 142km section of transmission line being duplexed, where the single electrical wire was replaced with two wires, to increase the northward transmission capacity for New Zealand from about 600MW at present, to about 1000MW.

The upgrade will allow electricity generated at the Manapouri Power Station in Fiordland, used by Rio Tinto’s Tiwai Point aluminium smelter at present, to be fed into the national grid after the smelter closes, and is a significant part of Transpower’s support to shift New Zealand to electrification and a low-carbon economy by 2030.

Transmission projects of this type and size would usually take several years to complete, Mr Noble said. In this case, with the threat of the Tiwai closure, some innovative works planning and delivery had resulted in the project taking just 18 months.

Importantly, that intensity did not come at the expense of safety, there having been a "near-perfect" safety record over the 245,000 hours worked, he said.

The project team tackled several challenges, from supply chain constraints to Covid-19 lockdowns and changing alert and traffic light levels. The final section traversed the remote Danseys Pass, which had tricky terrain and variable weather conditions. Transpower also worked around farming constraints, such as lambing, and through many public areas.

Project manager Phil Cross said the company was "very lucky to have the backing and co-operation of the local community" and he thanked everyone for their support and patience.

"Landowners have gone out of their way to accommodate our work crews, with some even bringing them home baking."

In the Waitaki district for the final stage, the Tokarahi Golf Club became the base for Transpower’s specialist wiring crew. In Oamaru, the company hired holiday houses for crew members to live in for the three and a-half months.

In total, the project involved the stringing of more than 900km of new conductor and the installation of 27,100 insulators.

Three new pylons were installed and about 300 pylons had their foundations strengthened with concrete encasement.

Substations in Naseby, Livingstone and Roxburgh also had their equipment upgraded to accommodate the duplexed line.

A key driver for restarting 18 months ago was the possibility of the Tiwai aluminium smelter closing.

Transpower grid development general manager John Clarke said the project was the first of many expected to aid New Zealand’s shift to electrification and a lower-carbon economy.

"All this and more will be needed as we move totally away from carbon to a renewable mix of energy sources such as hydro, wind, geothermal and solar," Mr Clarke said.