The McConnell Dowell, SNC Lavalin, and Parsons Brinckerhoff JV was awarded the EPC contract for the 166 MW Te Mihi Geothermal Power Station in January 2011.
Te Mihi is one of two new geothermal power stations planned for the Taupo region, designed to replace the the world's second largest power station - the 50 year old Wairakei Power Station. Two units of 83 MW were supplied to the consortium by Toshiba International Corporation.
- 495,200m3 earthworks
- 5,550 lm piles
- 15,800 m3 concrete
- 2,050 tonnes reinforcing steel
- 1,390 tonnes structural steel
- 3,880 lm electrical duct banks
- 5770 lm underground mechanical pipe
- 4100 lm carbon steel mechanical pipe
- 233,000 lm electrical cable
- 1340 lm FRP condensate pipe
With limited experience in complex EPC contracts in New Zealand, the Joint Venture secured a strong JV team with indisputable international expertise in applying the EPC model to construct power plants and meet Contact Energy's specific requirements.
The project required 450 staff during the peak construction time, with the project team delivering the works on an isolated 18 hectare greenfield site in difficult geotechnical (geothermal) conditions, under strict environmental and health and safety regulations.
The first turbine table was poured in April 2012, a culmination of four months intensive design, planning, temporary works and construction. The table supports the steam turbines and generator for Unit 1. The condenser unit for Turbine Hall 1 arrived at the Port of Tauranga and took more than 36 hours to unload from ship due to its large size.
A 1.5 hectare materials and equipment laydown were constructed on-site to receive, store and distribute procured items during the construction period. This area was a designated MAF receiving zone under JV supervision and fully security fenced and floodlit with controlled access using a “Cardex” swipe system. Full quality control and assurance was established on-site, within New Zealand, and overseas for the manufacture, procurement and receipt of over NZ$165M worth of permanent plant and equipment.
The earthworks design achieved an almost zero “cut to fill” balance. Both bored and drive piles have been used to maximise structural capacities within the various soil conditions thus minimising costs. A specialist concrete mix using local materials for use in the geothermal ground conditions was developed in conjunction with the supplier (Firth) and the JV.