Classifying geothermal systems
In the Bay of Plenty region geothermal systems have been classified into management groups which reflect their unique values and current uses.
Classification works on assigning geothermal systems into different management groups, depending on their biophysical characteristics and taking into account significant existing use, the process is set out in the Regional Policy Statement.
The purpose of the classification is to manage geothermal sustainably by establishing different management purposes for different systems ranging from protection of some geothermal systems for their intrinsic values, through to large-scale use of geothermal.
The challenge is to protect intrinsic and traditional cultural values while providing for the use of the energy resource. Council does this by taking a region-wide approach, providing for different values at a regional level rather than trying to provide for all values within each system.
The six management groups are:
Group 1 – Protected Systems
Waimangu-Rotomāhana-Tarawera, Whakaari (White island), Moutohorā Island (Whale Island).
These contain numerous significant surface features where the vulnerability to extractive use is moderate to high. Surface feature values override extractive values. Protection of the Significant Geothermal Features (SGF), which have outstanding natural, intrinsic, scenic, cultural, heritage and ecological values is a priority. No potential for extractive use.
Group 2 – Rotorua System
In this system there are high levels of existing use, both extractive and non-extractive. Numerous Significant Geothermal Features, some with outstanding characteristics where the vulnerability to extractive use is moderate to high. The Surface feature values rely on reservoir pressure and temperature maintenance and override extractive values. System management that limits extractive uses to avoid, remedy or mitigate adverse effects on the outstanding natural, intrinsic, scenic, cultural, heritage and ecological values. Limited potential for further extractive use.
Group 3 – Conditional development systems
Rotomā - Tikorangi, Taheke, Tikitere - Ruahine, Rotokawa-Mokoia Island
Varying levels of existing use in these systems. Mainly non-extractive. Some Significant Geothermal Features, where the vulnerability to extractive use is moderate. The values of Significant Geothermal Features have priority over extractive values. System management will provide for use and development, contingent upon the ability to avoid, remedy or mitigate significant adverse effects of development on the Significant Geothermal Features present in these systems. Potential for development of extractive use (heat or fluid).
Group 4 – Development systems
Kawerau, Lake Rotoiti (outflow is in the bed of the lake), Rotomā - Puhi Puhi.
Varying levels of existing extractive use in these systems. Few or no Significant Geothermal Features with moderate to low vulnerability to extractive use. System management that provides for extractive use, provided significant adverse effects on Significant Geothermal Features are remedied or mitigated. Potential for development of extractive use (heat or fluid).
Group 5 - Low temperature systems
Tauranga/Mount Maunganui (Mauao), Pāpāmoa/Maketū, Awakeri, Mayor Island (Tūhua), Pukehīnau (Rangitaki), Manaōhau (Galatea).
Varying levels of existing extractive use in these systems. Few or no Significant Geothermal Features vulnerable to extractive use. System management that provides for extractive use, where the adverse effects of the activity can be avoided remedied or mitigated. Discharge of geothermal fluid must be managed to avoid significant adverse effects on surface water and stormwater.
Group 6 – Research systems
These are newly discovered or researched systems that we don’t know enough about. This category allows for research into the characteristics of a system in order to enable its reclassification into the appropriate management group. Geothermal takes and discharges are only allowed for investigation purposes and only where it can be demonstrated that there will be no permanent threat to significant geothermal features or to the natural characteristics of the system.