Contact Energy


Client: Contact Energy
Site: Taupo - Wairakei
Project: Te Mihi
Duration: 5 Months

Contact Energy is one of New Zealand’s leading generators of geothermal electricity, generating around five per cent of New Zealand’s total energy from its geothermal operations in the Taupo region.

As New Zealand’s demand for energy continues to grow and concern about climate change increases, new sources of renewable energy are needed.

Geothermal energy uses the heat from deep inside the earth to generate electricity – it’s renewable, capable of generating large amounts of electricity and, unlike wind and hydro generation it does not depend on the weather.

Electricity produced from geothermal energy is always available, providing a vital role in a secure power supply.

The Te Mihi project is a $750 million programme of investments that safely and sustainably expands the use of the Wairakei steamfield. It includes the construction of a new power station, a bioreactor to remove hydrogen sulphide from cooling water discharged to the river, life extension work at the Wairakei geothermal power station and the drilling of production and reinjection wells.

Our brief was to put into service two recently drilled production wells designated WK123 and WK124 and install a separation system to supply steam and geothermal fluid to the Wairakei Power Station. This was a major upgrade of services to the Wairakei station that was originally commissioned in 1958.

Our work included:

  • Cadwelding and bonding of all equipment foundation pads
  • Design and installation of two lightning protection system including air receiver and 3 point ground earth
  • Installation of cable supports and ladder rack with peaked lids
  • Installation of Steel Wire Armoured (SWA) cabling to motorized actuator valves
  • Profibus ring communication network from PLC to all actuator valves for positional and alarm event monitoring
  • Installation of SWA cabling to all instruments and digital devices
  • Supply and installation of pressure, temperature, orifice plate flow transmitters, vortex flow transmitters, ultrasonic flow transmitters, radar level working as a flow transmitters
  • Fabrication of all instrument piping using Swagelok fittings
  • PLC documentation, site specific core wire identification and cable labeling systems
  • Site wiring of all actuators, temperature controls, level controls, pressure controls, flow controls
  • Extensive bonding system of all cable racks, instrument stands, foundation supports
  • Surface bonding of insulated cladding around steam pipes
  • Documented pre-testing of all cabling and instrumentation
  • Upgrade of existing two switchboards
  • Software testing of all actuator and instrumentation
  • Commissioning, calibrating, operator training and as built documentation