Tauranga, Group 5
The Tauranga Geothermal System is a large low-temperature geothermal system (between 30°C and 70°C) that shares similar aquifers as the cold groundwater resource.
A few warm springs are found at the surface which have been used for bathing, with the system being tapped by many bores utilising the waters for commercial and domestic purposes. It extends over 60 km from Katikati-Waihi Beach in the north-west to Te Puke-Maketu in the east, with the dominant heat source appearing to lie near Tauranga city.
Draft Tauranga Geothermal System Management Plan
Bay of Plenty Regional Council is currently reviewing how the Tauranga Geothermal System is managed.
We have created a draft system management plan (SMP) that sets out how we will work operationally, some of the challenges and opportunities, and specific actions we will take to manage the system.
System management plans are required for systems of high use as set out in the Regional Policy Statement. In the Bay of Plenty this currently includes:
- Ngā Wai Ariki o Rotorua – The Rotorua Geothermal System (adopted 2024)
- Kawerau Geothermal System (currently under review)
- Tauranga Geothermal System (draft open for feedback)
The draft Tauranga Geothermal System Management Plan is still in the early stages of development, and we are seeking feedback from those who live, work or operate a business in the Tauranga Geothermal System.
As well as the draft Tauranga Geothermal System Management Plan, we have also released a draft Plan Change 11 for feedback.
Plan Change 11 will see a review of the geothermal objectives, policies and rules in both the Regional Natural Resources Plan and the Rotorua Geothermal Regional Plan, and will combine these into a single geothermal chapter in the Regional Natural Resources Plan.
New research into 'geoheat'
To better understand the potential of this, Bay of Plenty Regional Council has commissioned a report that investigates if geoheat in the western Bay of Plenty has potential to be used for renewable energy, and, most importantly, if it is sustainable to do so.
The focus of the report is on the low temperature Tauranga Geothermal System (30°C - 70°C), but geoheat also includes use of non-geothermal water for heating and cooling, so the potential application as a renewable and sustainable source of energy is much broader.
Surface features
There are a few natural warm springs, generally with water temperatures below 35°C. Sapphire Springs south-west of Katikati was sampled at the start of the twentieth century (1904), but there is little observational detail on the spring or its use. Today the spring is diminished with hot pools being sourced from groundwater bores.
Hot springs located around one kilometres south-west of Maketu have been documented as being bathed in by local Māori in the late 1800s (Matherson, 1998). Springs were likely to have been in a wetland area and may have been reduced with drainage development in the area for farming.
Use and development
Hot water has been extracted from the system for about the last 40 years for heating, cooling, tropical fisheries, bathing and greenhouses. Water is also extensively used for irrigation and frost protection being the dominant use of the geothermal use in the resource in the commercial sector. The system has traditionally been monitored for groundwater flow but increases in use have also caused concern about the management of the heat within the system. Low-temperature (<150°C) geothermal resources are becoming an increasingly attractive energy source as technology improves and traditional energy sources become scarcer.
There is potential that parts of the Tauranga Geothermal System are sensitive to permanent cooling if overused. If too much geothermal water is taken, then cool water may replace the warm, cooling the heat left in the rocks and potentially taking many years to regenerate.
Managing the system
Council is completing further scientific research in order to better understand the attributes of this geothermal system. To help better model the extent of the Tauranga Geothermal System in terms of its depth and geographic scale, geothermal bores and groundwater takes are being monitored and tested. Once a better understanding of the science is achieved, work will continue with key stakeholders and the community to develop new policies and rules to help ensure the long-term sustainability of the geothermal system.
For more information on the science behind this system, you can read a summary of our report: