Major earthworks and civil works are well underway for the construction of the power station platform and the drilling pads for the production wells. Over 700,000 cubic meters of dirt will be excavated over three summer periods from October to April, with completion of civil works in 2020. These works are being undertaken by Whangarei based United Civil Construction with a largely locally based workforce.
Once the well platforms and water management system are in place in early 2018, well drilling will get underway. Two working production wells and two reinjection wells are needed.
Typically, the wells will be 1,750 metres deep and be one metre in diameter at the surface and 22.5 centimetres at their deepest point. Drilling each well is expected to take around 30-40 days of continuous 24/7 activity, with additional time needed to move the drilling rig between well sites. This means that it could take around 12 months or more to complete well drilling for one power station. The wells will be tested to ensure that the geothermal resource meets operational requirements.
Iceland Drilling, with decades of experience in the field of geothermal drilling, including the Ngatamariki geothermal power station near Taupo, will send a specialist team and be based in Northland for one year from April 2018.
The components of the power stations will mostly be built offsite and will arrive in modular form. This means that they will require minimal construction and it will only take about 12 months to complete the power station build.
Israeli geothermal plant construction experts ORMAT have the contract to design, build and supply the power station which will commissioned in 2021. ORMAT has a long history with the operations at Ngawha supplying the original 10 megawatt power station, which was commissioned in June 1998 and then expanded to 25 megawatts in 2008.