Ngāwhā geothermal project steams ahead; drilling starts soon

Drain installation on the plant's newly finished platform.

Progress is steaming ahead on the Ngāwhā Geothermal Power Station expansion with drilling on track to start this month.

The drilling will bring the $176 million project closer to Top Energy's aim to double the existing geothermal station's 25 megawatts capacity.

The expansion could supply enough energy to power the whole of the Far North and has been described by Top Energy chief executive Russell Shaw as ''a game changer''.

The boosted capacity will radically improve the security and reliability of the power supply for the whole Northland region, Shaw said. Work started on the expansion in December.

"Our reliance on the national grid, which transports power from the south, will be substantially reduced," he said.

"Ultimately, expansion of the Ngāwhā power station could secure the region's energy independence, with clear benefits for local consumers by providing a renewable and lower cost source of generation and power."

Despite recent wet weather, good progress was made over the summer to complete the pad for the production wells.

Looking well contained, this is the foundation for Northland's greatly expanded geothermal power supply.

Iceland Drilling, the Icelandic company contracted for the well drilling, has established a site compound and its team is ready to start drilling the first production well.

The company's HH-220 Drillmec rig arrived at Northport on April 25. A massive transport operation then took about 60 trucks over six days to get the rig to the Ngāwhā construction site.

The big rig differs from conventional types with its high level of mechanisation reducing operator input and the risk of injury. Compared with rigs of equal power and capability, it also creates a smaller carbon footprint, reducing environmental impact.

The rig will drill two production and two reinjection wells 1750m deep and 1m in diameter at the surface, reducing to 22.5cm at their deepest point.

Drilling each well is expected to take around 30-40 days of continuous 24 hour a day activity.

Whangārei-based United Civil Construction undertook the key preparatory work for the power station platform and will soon complete the reinjection well pad.

Major earthworks will continue on the platform and geothermal fluid pipe routes over two more summers, with completion scheduled for early 2020. Over 700,000cu m of dirt will be excavated overall.

Israeli geothermal plant construction expert Ormat has the task of designing, building and supplying the power station which will be commissioned in 2021.

Ormat built the original 10 megawatt station, commissioned in 1998, and the first expansion to 25 megawatts in 2008.