Transpower identified the need to increase capacity and resilience at the Waiotahe substation, its main supply point for the Eastern Bay of Plenty. Northpower was engaged to deliver a staged redevelopment that strengthens security of supply while enabling the connection of new solar generation in the region.

The project involves installing two new three‑winding transformers, upgrading protection systems and constructing new 33kV infrastructure. Together, these upgrades future‑proof the substation to support Horizon’s network growth and two new solar farm connections, one of which is already commissioned.

Substation redevelopment requires highly specialised technical skills and careful sequencing. At Waiotahe, work began with significant civil preparation, including extensive surveying and the careful exposure of legacy underground services to safely enable construction alongside live equipment.

Northpower then installed two new 110/33/11kV three-winding transformers and completed 110kV line deviation and protection upgrades to safeguard the site. A new indoor-33kV switchgear building has been completed to allow Horizon Networks to transition from 11kV to a fully 33kV‑supplied network, improving long‑term reliability and capacity.

Throughout delivery, the team carefully planned outages and sequencing to minimise disruption, recognising that Waiotahe is the sole main supply to the western East Cape region. This required close co-ordination across transmission, substation and civil workstreams to keep outages as short and infrequent as possible.

The success of the Waiotahe upgrade reflects close collaboration between Northpower, Transpower, Horizon Networks and delivery partners. Open communication, shared planning and the ability to mobilise diverse skill sets across transmission, substation and civil disciplines enabled the team to respond to tight timeframes, complex outages and unexpected challenges.

Once complete, the upgraded Waiotahe substation will provide a more stable, higher‑capacity supply for Eastern Bay of Plenty communities, support renewable generation and extend the asset’s service life for decades to come – delivering practical, long‑term value for the client and the region.