14 Apr 2022
Transpower has completed its Clutha to Upper Waitaki Lines project with the commissioning of the final works to replace conductor (the wire) on the Roxburgh to Livingstone section of the Roxburgh to Islington A 220 kV transmission line this week. The total project has nearly doubled the transmission capacity of the network for transfer northwards — particularly important for either new generation in the area or the potential closure of the aluminium smelter at Tiwai.
The 142km section of transmission line, between Roxburgh in Central Otago and Livingstone in the Waitaki Valley has been duplexed, where the single electrical wire per phase has been replaced with two wires. This together with other work as part of the wider project has increased the northward transmission capacity for New Zealand from around 600 MW to approximately 1,100 MW.
Project Director Roy Noble says “The commissioning of the duplexing project is a significant milestone for Transpower and 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. Completing the project ahead of schedule, and safely, is a testament to the dedication of our service providers and wider project team.”
It has been an intense work-front for the project team. Transmission projects of this type and size normally take several years to complete. In this case, with the threat of Tiwai closure, some innovative works-planning and delivery have seen the project take just 18 months. Importantly that intensity hasn’t been at the expense of safety with a near perfect safety record for the 245,000 hours worked.
The duplexing project has tackled many challenges, from supply chain constraints through to COVID-19 lockdowns and changing alert and traffic light levels. The final section of the project traversed the remote Danseys Pass which offered tricky terrain and extremely variable weather conditions. In addition, teams have worked around farming constraints like lambing and fawning, and through highly public areas such as Alexandra and over the Otago Central Rail Trail. The project has been successful thanks in a large part to the support of the local community. “We have been very lucky to have the backing and cooperation of the local community” says Project Manager Phil Cross. “Landowners have gone out of their way to accommodate our work crews with some even bringing them home baking. We’d like to thank our landowners and the wider community for their cooperation and patience while this important project has been underway.”
In total, the project has strung over 900km of new conductor and installed 27,100 insulators. Three new pylons have been installed and nearly 300 pylons have had their foundations strengthened with concrete encasement. Substations at Naseby, Livingstone and Roxburgh have had their equipment upgraded to accommodate the duplexed line.
The Clutha Upper Waitaki Lines Project has spanned many years — with these final works held over initially until the economics of undertaking them improved. A key driver for restarting in the last couple of years was the possibility of the Tiwai aluminium smelter closing. The first two components were delivered in 2015 and 2016, and in 2020 Transpower completed the third component, a thermal upgrade of the Cromwell to Twizel section of the Roxburgh-Twizel 220kV transmission line.
The Clutha Upper Waitaki Lines Project is a significant part of Transpower’s support to shift New Zealand to electrification and a low carbon economy by 2030. Transpower’s General Manager Grid Development, John Clarke says the project is the first of many works expected over the medium term to facilitate that shift: “This project has been about increasing the capacity between the lower South Island and areas further north. We also have investigations underway on our capacity in the Central North Island, around Wairakei, and the interisland HVDC submarine cables. All this and more will be needed as we move totally away from carbon to a renewable mix of energy sources — like hydro, wind, geothermal and solar.”
Downloads
Media Release — CUWLP Commissioning