Investigating the geoheat potential of the Tauranga geothermal system

Abstract

The Tauranga Geothermal System (TGS) covers an area of approximately 875 km2, extending from Waihi Beach in the north to Te Puke-Maketu in the south. Being a low temperature single aquifer geothermal system, it ranges in
temperature from ~15 °C (ambient) to ~70 °C at depths of 700m. Although these temperatures are too low for electricity generation, they have good potential for heating.
Geoheat is the use of geothermal energy for heating purposes either directly or indirectly, using heat pumps. Current geoheat applications in the TGS include bathing, space heating, water heating, irrigation and frost protection. Due to its ability to replace gas heating and to reduce electrical demand and carbon emissions, geoheat is an important part of the energy transition.
To this end, the Bay of Plenty Regional Council (BOPRC) commissioned an investigation into the geoheat potential of the TGS.
The investigation adopted a holistic approach by integrating the technical groundwater and geothermal elements with stakeholder consultation on current practices, management implications and how these align with regional economic development considerations.
Resource characterisation of the TGS presents a readily accessible source of sustainable thermal energy. Integrating this finding with socio-economic factors further concludes that geoheat use of the TGS could provide significant energy, economic, environmental and health benefits to the region.
Greater use of the TGS’ geoheat potential must be balanced with sustainable management of the resource. This report outlines guidance to ensure good system design, appropriate technology selection, and ensuring compliance of pinstallation techniques. This work will inform the Tauranga System Management Plan (which is currently being developed by BOPRC). It will also guide any future changes to balance the environmental and economic benefits of an increased uptake of geoheat with the long-term sustainability of the resource.