Meridian Energy

Manap?uri - Transformer Replacement Project

Manapouri Transformer Replacement Project

The discovery of aluminium contamination in three transformers at Meridian Energy’s Manapouri power station in May 2014 required an urgent response.

While not an emergency situation, two transformers were immediately taken out of service, critically impacting the operation of the country’s largest hydro-electric plant.

Replacement was treated with urgency to bring the station back full capacity as fast as possible, coupled with care to ensure quality was not compromised.

Multiple work streams, including transformer supply, site enabling works and installation works, were carried out in parallel to compress the delivery timeframe.

Further complicating the project was its convergence with the 2014/15 Christmas break, which not only required that project staff work through their own holiday period, but meant the project would be competing with a busy Fiordland tourist season.


Three bespoke transformers were supplied by Melbourne-based Wilson Transformer Company (WTC). Meridian planned to condense the usual 18- to 24-month procurement process to 12 months; in fact the first transformer was delivered in 19 weeks and back in service after 22 weeks.

Central to the timeliness of the project was Meridian’s conviction that delays were not an option.

It conducted a series of reviews with the transformer manufacturer to sign-off of componentry as it became ready, and regularly sent its own engineers to the factory.

In addition, WTC provided a 3D model of the transformer so that any engineering constraints could be assessed early, and the transformers were tested against Meridian’s dummy control system. This was to expose any gaps between the transformer and the special characteristics of the control systems, which Meridian recognised was a potential stumbling point for the project.

When a vessel scheduled to collect the first transformer from Melbourne ran late, 18 road transport permits were secured to truck the transformer to Brisbane and meet an alternate vessel.


Manapouri lies in a remote part of Fiordland National Park, a UN World Heritage area. Stakeholders and consenting authorities were engaged early to minimise risks associated with resource consent.

A large freighter had to be brought into Deep Cove and was subject to anti-fouling, sound and speed constraints. A mammal watch was also required from the ship’s deck.

A self-ballasting vessel was selected to avoid ballast water entering Doubtful Sound, and biosecurity inspections were carried out before the ship entered New Zealand waters. The project was completed without serious harm to anyone or environmental incident.

Meridian also worked with tourist operators to coordinate loads across the steep and winding Wilmot Pass, which is also used by tourist buses, and to minimise disruptions at Deep Cove wharf.

As the Manapouri project was fast-tracked, schedules and budget weren’t prepared before work started but elaborated on the run. The approved budget for the project was $9.505 million and final outturn cost was $9.526 million.

The supply chain was managed tightly, helped by a communication plan established at the outset, to engage all levels of supply. Meridian says informal communication efforts were just as helpful to the project - one project manager temporarily relocated to Manapouri to be hands-on with local stakeholders.

The Energy Project of the Year award category is sponsored by UGL