Giant Transformer Is Safe, Sound And Underground

Following a stunning journey worthy of a Hollywood blockbuster, Meridian’s Manapōuri Power Station has taken delivery of a new transformer that’ll give the hydro station a huge – and timely boost. 

A 104-tonne transformer’s not a quick or easy thing to transport, with the New Zealand leg of the journey taking place over several carefully planned days last week. 

After arriving in Bluff from Australia, the 135 MVA transformer was unloaded onto a trailer for the 170 km journey by road to Supply Bay, before spectacularly making its way by barge across Lake Manapōuri. 

It was the first time a piece of generation equipment this size has travelled by barge across Manapōuri - items this large have previously used Deep Cove in Doubtful Sound and then been transported over Wilmot Pass. 

Following the slow and scenic journey across Manapōuri, the transformer was delicately reversed down a two-kilometre road access tunnel into the cavernous machine hall.

“There were plenty of early starts and late finishes, but our Meridian team and suppliers have achieved an outstanding result for New Zealand’s electricity supply ahead of Winter ‘25,” says Meridian acting GM Generation Yanosh Irani.

“This has been months of work, planning, and coordination, and the specialist skills on display have been amazing - Meisters for barge operations, Move Logistics for transportation from Bluff to Supply Bay and then again at West Arm, and E-Type for fabricating and installing two unloading wedges for the delivery. A real – and world class – team effort.”

Manapōuri Power Station has been operating at reduced capacity for around two years, following the discovery of faults in two of its seven transformers, so the arrival of the first replacement transformer is a major milestone. 

“We saw this winter just how important every single megawatt is, so this transformer has landed at a brilliant time,” says Yanosh Irani.

“Getting our biggest power station closer to full capacity will boost security of electricity supply next winter and, in the meantime, give us the ability to ease off generation in the Waitaki to help restore storage levels in Lake Pūkaki.”

The new transformer will increase generation capacity at Manapōuri from the current restricted limit of 640 MW to around 768 MW – close to the maximum 800 MW allowed under its consent conditions.

Work to commission it is expected to be completed by Christmas, and the second replacement transformer (along with a spare) is due to arrive in late 2025.

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