Te Huka Power Station

The Project

McKay was engaged as the electrical contractor for the complete electrical construction and commissioning of the Te Huka Geothermal Power Station, a 59.5 MW generation facility owned by Contact Energy. McKay’s scope encompassed all electrical installations, inspections, and testing of critical generation and auxiliary systems, from HV/LV infrastructure through to automation cabling and final certification. Responsibility extended across all electrical infrastructure up to the overhead 33 kV connection to the Grid Exit Point, making McKay the single accountable party for the facility’s entire electrical package. The project was delivered on time and within budget, enabling Contact Energy’s geothermal facility to be seamlessly integrated into the national grid.

Project Deliverables

McKay’s scope covered the installation, inspection, and testing of all major electrical equipment and systems across the Te Huka facility.

Generation & Transformer Infrastructure: Installation and commissioning of the 59.5 MW 11 kV synchronous generator, a 60 MVA ONAN 33/11 kV oil-immersed main transformer, three 2.6 MVA 11/0.4 kV auxiliary transformers, and one 15 kVA 11/0.18 kV auxiliary transformer.
Backup Generation: Installation and commissioning of a 475 kVA 400 V diesel backup generator to ensure operational continuity in the event of a grid outage.
Switchboards: Installation of one 33 kV switchboard and one 11 kV switchboard, forming the core of the facility’s high voltage distribution network.
Motor Control Centres & Drives: Installation of four 400 V motor control centres (MCCs), complete with variable speed drives (VSDs) and 14 associated pumps and fans across the plant.
110 V UPS Systems: Two independent UPS systems were installed, each comprising a 110 V 22 kW charger, 5 kVA inverter, and comprehensive DC distribution. Battery racks were configured with 45 cells in a 5-string arrangement at 185 Ah per cell, with integrated battery isolation cubicles, external test points, and a centralised DC distribution panel.
Motor UPS Inverter Systems: Three 45 kVA three-phase motor UPS inverters were installed, each supported by a battery rack with 27 cells in a 3-string configuration at 185 Ah per cell, complete with isolation cubicles, external test points, and dedicated three-phase distribution panels.
Services Distribution Boards: Two services distribution boards installed to support ancillary electrical loads across the facility.
Control & Automation Cabling: All control and automation cabling and terminations were installed and tested across the site.
Final Inspection & Certification: McKay completed the full electrical inspection, testing, and certification of the entire installation in accordance with stringent safety, quality, and environmental compliance requirements.

Our Approach

Te Huka required McKay to operate as a true multidisciplinary electrical contractor, managing HV and LV systems, motor control, automation, and complex battery backup infrastructure under a single, coordinated delivery. The battery backup and power management scope was particularly involved, with two independent 110 V UPS systems and three motor UPS inverter systems all requiring precise configuration, integration, and testing to ensure the facility could maintain operational continuity under any conditions.

Working across generation, distribution, control, and backup systems simultaneously demanded rigorous programme management and close coordination with Contact Energy’s technical teams. The result was a fully certified, grid-ready facility delivered on time and within budget, a strong demonstration of McKay’s capability at the heavy end of electrical construction.