Towards Zero Carbon

Ngāwhā Geothermal Power Station is live

Energy Futures

One of the largest projects ever undertaken in Northland has had GNS Science expertise and planning input. The 32MW Ngāwhā Geothermal Power Station near Kaikohe, owned and operated by Top Energy, went live in December 2020.

The new power station secures an independent, renewable and affordable power supply, ending the region’s reliance on the national grid and electricity being transported up from the south.

Geothermal energy from the new power station supplies 95 percent of the Far North’s electricity demand for the year, thanks to input from a GNS Science team’s specialist expertise in planning geothermal energy developments. Excess power is exported to the rest of Northland through the national grid.

GNS Science’s role has spanned the life of the project from feasibility studies to well testing. It started with production of a numerical reservoir model that was used to assess the feasibility and impact of the proposed expansion. Then a detailed three-dimensional model of the geothermal reservoir was used to help in the positioning of the new wells.

GNS geologists were present on the rig during the drilling programme. After the wells were drilled, scientists developed a test programme and analysed the results to provide estimates of their capacity.

Image caption: 32MW Ngāwhā Geothermal Power Station near Kaikohe. Credit: Top Energy Ltd.

Top Energy have begun a three-year period of monitoring the geothermal field to ensure that the field performs similarly to the model prepared by GNS Science.

Electricity generated from geothermal energy will play an increasingly important role in New Zealand’s energy mix. It offers a renewable energy source that is not susceptible to climatic conditions, such as wind, sunshine, or rainfall. The generation model also sees the geothermal fluids extracted injected back into the underground reservoir, minimising environmental impacts and maintaining the reservoir fluid mass.

Energy consumption is expected to rise sharply in coming decades as New Zealand electrifies various sectors in moving to a low-carbon future. As the energy Crown Research Institute, GNS Science is a vital player in helping to unlock geothermal resources for New Zealand.

“The team from GNS Science was instrumental in the development and delivery of the well drilling programme at Ngāwhā. Their support and responsiveness helped ensure the programme was delivered in a timely manner and our knowledge of the geothermal resource has increased significantly.”
Thomas Zink, Project Director Ngāwhā Expansion Project, Top Energy Ltd.

Image credit: Geothermal pipes at Wairakei. Credit: Margaret Low

Image credit (top): Geothermal pipes at Wairakei. Credit: Margaret Low

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