Craig Oliveria, Beca

Craig is a first year graduate engineer from Massey University who joined the Beca Central Power team as a Transmission Line Engineer. In his role, he is responsible for detailed design of high voltage power poles, towers and lines, gaining valuable experience while working on a range of projects throughout New Zealand and Australia. Craig is passionate about sustainable design and manufacturing innovations leading the world towards a Carbon Zero future.

Sustainable Transmission Line designs in to reduce Concrete consumption

While it may seem that transmission lines have little impact on carbon emissions, there are small changes that can have a large impact on sustainability. In addition, these changes can result in significant economic benefits. Reducing concrete use, upgrading existing lines, and recycling materials can all make a difference.

Approximately one kilogram of carbon dioxide is released into the atmosphere for each kilogram of cement. Therefore, innovations in transmission line design to reduce concrete consumption have the potential for significant reductions in CO² emission.

In 2017, Beca Ltd (Beca) was commissioned to investigate the economic benefits of using cathodic protection instead of concrete over grillage to extend the life of the tower foundations. Cathodic protection consists of sacrificial anodes to extend the life of steel grillage foundations on transmission towers.

The client's existing strategy was to refurbish foundations at approximately 250 towers each year by installing concrete over the corroding grillage foundations.

Installing concrete over grillage foundations comes at a considerable cost and uses a significant amount of concrete.

The results of the investigation found that cathodic protection, tailored to New Zealand's varied soil conditions, has the potential for significant savings of capital expenditure over the life of the asset along with significant reduction of the use of environmentally harmful concrete.

Edward Popham, Transpower

Edward studied mechanical engineering at the University of Canterbury and joined the Transpower graduate program in March this year. Since March, he has contributed to lines projects in Transpower's southern network and experienced first-hand the work involved on re-wiring a section of line in the Rangitata area.

Edward is new to the power industry and excited about contributing towards New Zealand's electrification and carbon zero goals.

Water beats towers. Are poles more in our future?

Rangitata Flood Response - Rebuild of 220kV Single Circuit Line

On the 7^th of December 2019 the Rangitata River, which passes 29kms south-west of Ashburton, was flowing at around 2265 cubic metres a second and approaching the highest flood levels in 20 years. Transpower own three 220kV tower lines that cross the Rangitata River around state highway 1. During the flood Transpower had 7 towers damaged or completely wiped out! A flood response project involved commissioning a temporary pole line to provide Christchurch with a secure winter power supply before building a permanent tower line due for commissioning end of August.

The unique part of this project was the temporary pole line and the foundations used. Poles are commonly used for electricity transmission, but this is the first time concrete poles that are normally used on 110kV lines were used on a 220kV line. Small stretches of steel poles are used on 220kV lines already at Otahuhu Auckland and South Dunedin where a pole comes in handy with its smaller footprint. It would be interesting to see if this pole design would be suitable for a 220kV permanent replacement or if they would phase out tower replacements in the future.