The Clyde Dam transformers have reached the end of the line and are being replaced by owner operator Contact Energy, who said it was “a mammoth job”, involving a 25-strong project team and global cooperation. 

The first new transformer was manufactured and shipped from South Korea – a journey that took longer than anticipated due to Covid-19 and weather related challenges.

A big day for project manager Kirk Pritchard, taking delivery of ‘big red’.

Contact Energy project manager Kirk Pritchard said as well as physical logistics they had hit up against Covid-19 related delays. 

“We had to do testing over Zoom and the shipping has been impacted... There were multiple delays due to hold ups in port and lockdowns in China. Most recently there was an outbreak of Covid on the ship before it was due to pick the transformer up in South Korea.

“This meant the ship had to go to Vietnam and get a new crew before it could go to pick the transformer up. This pushed the arrival into June, so now we await to see if we have further weather-related delays for the truck journey. The joys of unusual equipment delivery.” 

Contact hoped the transformer would get to New Zealand in March, but it arrived yesterday afternoon in Clyde after coming via Auckland on an international cargo ship, then by boat to Timaru and by road through the Lindis Pass.  

Two truckloads of additional parts need to be reassembled in the Contact Energy workshop, to make the transformer function.

The Contact team wanted to celebrate and support diversity which is why each of the transformers will be painted a different colour from the pride flag.

Kirk said as a rainbow tick accredited employer the Clyde based team wanted to make a bold and tangible statement embracing diversity. 

“We thought painting the transformers in the colours of the pride flag would be more impactful and enduring than a flag up a pole. The first transformer is bright red and the second will be orange. 

“Consideration is still being given as to how we may capture the sixth colour, the dam itself was considered but that’s a lot of paint.

“[The transformers] are a little bit hard to see from the main road but are located on the downstream side of the main powerhouse building.”

The four other transformers will be replaced over the next few years. Each one is around six metres long, four metres wide and almost five metres tall.  

The bay is empty ready for the new transformer to be installed. 

“[The transformers] needed to be shipped from Busan Port to Auckland Port to Timaru Port and then shipped to Clyde on a heavy transport truck. 

“These are hefty bits of equipment to get over complicated terrain such as the Lindis Pass, in June no less…The width is … still a lot wider than a normal truck. 

“The weight is the biggest factor, at 96 tonnes which means combined with the weight of the truck it is a fairly significant heavy load. All up including the trailer that it is being moved on, it will weigh nearly 140 tonnes.”

Kirk said all up the transformer replacement project will end up being worth around $20 million. 

The transformer travelled along the top of the dam at a snails pace for safety reasons, allowing the project team to keep pace with part of its journey. 

The project started in January 2021; the contract was agreed with South Korea’s Hyosung Heavy Industries in June 2021; and the design completed in October 2021. Manufacturing and testing was completed in March 2022 then it was loaded to be shipped here. 

“Once the truck gets to site, the trailer is pushed into the powerhouse and the transformer is unloaded using the gantry crane,” Kirk said.

“Once it is unloaded it will be reassembled… filled with some 36,000 litres of fresh oil and then installed over eight weeks.”

The job of a transformer in a hydro station is to convert electric current for travel through transmission lines. They step up the voltage to allow it to travel through the power lines of the electrical grid – which means you can turn your heater on at home, or the coffee machine at work. 

The trailer had to be 12 axles long to be able to transport the weighty equipment. 

The original transformers at the Clyde Dam were installed when the dam itself was built on the Mata-Au (Clutha) river in the 1980s.

The dam is the third largest hydroelectric dam in New Zealand and was commissioned in 1992. 

It is also the largest concrete gravity dam in Aotearoa. It has a million cubic metres of concrete in the dam and another 200,000 cubic metres in the powerhouse. 

The hydro power station is capable of producing 432 megawatts (MW) of power from its four turbine generator units. 

The company also runs the nearby Roxburgh Dam, which was commissioned in 1956.