Tauranga geothermal system – an overview

Abstract

The Tauranga Geothermal System (TGS) is an extensive warm water system with few geothermal surface features. Geothermal-groundwater (GGW) is produced at 30-70 °C from wells mostly 200-600 meters deep. The TGS is available for sustainable use and development, and discharges are managed to minimise the effects on the receiving environment. The main uses are for space and water heating for municipal pools, private domestic space and water heating and mineral pools, and space heating for greenhouses. The use of GGW for irrigation and frost protection is not considered a ‘geothermal use’ nor a method of discharge. However, it accounts for around 24% of the allocated geothermal water from the TGS. This paper describes the current situation with geothermal takes and discharges from the TGS, aspects of chemistry relevant to the use and discharges to various receiving environments, and the current knowledge of the geothermal energy resource. This is based on published technical reports, historical data stored in the Bay of Plenty Regional Council (BOPRC) archives, and data from resource consent applications and compliance processes. BOPRC is currently building its body of knowledge on this large geothermal system to inform and improve the integrated management of this large geothermal-groundwater resource.