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Geothermal Energy

Geothermal fluid contains lots of heat energy and this has many useful benefits for society;

  • The energy is what creates the spectacular geothermal surface features like the geysers;
  • Hot mineral pools;
  • Providing direct heat for domestic and commercial use (through radiators and small scale heat exchangers); and
  • As a power source to create electricity.

Geothermal energy is considered a renewable energy - meaning with appropriate management the geothermal system will continue being able to provide geothermal energy indefinitely. However, geothermal energy is also considered a finite energy - there is only a certain amount available for everybody (cumulative use), and if we take too much the system can be severely damaged.
One of the best ways to use geothermal energy is to undertake cascading energy use - this means you use the same geothermal fluid multiple times before disposal, a couple of examples are below.

Industry

Fresh geothermal fluid is used in a power station --> spent fluid is then used to heat a hotel --> spent fluid is then used to heat an aquatic centre --> spent fluid is then used to heat up a fish farm --> spent fluid is discharged.

Domestic

Fresh geothermal fluid is used to heat a town supply water --> spent fluid is then used to heat a house --> spent fluid is used to heat a swimming pool --> spent fluid is used to irrigate/frost protect crops.
Note: The ability to cascade energy uses can be limited by the temperatures required for successful reinjection.

Ecosystems

There are many unique plants and organisms which have adapted to living in and around geothermal surface features. Geothermal surface features provide microclimates (they make the immediately surrounding area different than the wider environment) which allows plants and animals to develop and interact in ways that are found no-where else. In the Waikato/Bay of Plenty geothermal areas we have plant associations that are found no-where else in the world. All these species are uniquely important to our genetic biodiversity. Diverse life forms and their genetic material provides many unique opportunities for the future. An example of this is the use of bacteria that thrive at extreme temperatures being used in industrial processes. Who knows what geothermal ecosystems might provide us with next.

A number of geothermal vegetation surveys have been undertaken by the Bay of Plenty Regional Council, contact an Environmental Scientist on 0800 884 880 to obtain access to these documents.

Effects of Land Use

Geothermal surface features as well as being dynamic are also surprisingly fragile, and so land use around surface features is managed by the Bay of Plenty Regional Council. As well as the potential damage to the surface features, any work near surface features will also need to consider issues like health (some natural gases can be harmful at high levels), and site stability, as mentioned earlier geothermal sites are notoriously dynamic and can shift and change very quickly.
If you wish to undertake works near a surface feature you are likely to require a Resource Consent.
If you're planning on undertaking work within the Rotorua geothermal field, give our friendly Consents Team a call to see if there are any recorded geothermal sites that might be affected.

Rotorua Geothermal System

The Rotorua geothermal field and its features are considered a national treasure, in particular Geyser flat which includes Pohutu and Prince of Wales Feathers Geysers are considered nationally outstanding natural features. The geothermal surface features and unique ecosystems render the Rotorua geothermal resource of high international significance in terms of scientific and conservation values. The Rotorua resource has been studied intensely by international experts and is providing the basis for the evolution of many geothermal models and volcanic and geological theories.
Rotorua has long being considered a key tourist destination for New Zealanders and international visitors. The fact that the Rotorua geothermal attractions are visited by many thousands of overseas visitors every year attests to its value to the international public.
The careful management of this field is of extreme importance to the Bay of Plenty Regional Council, proven by our geothermal rules and our monitoring programme for the field.

       

History >>

Importance >> Problems >>

Geothermal Reports >>

Planning provisions

Using geothermal fluid or energy from the Rotorua geothermal field is considered under the Regional Policy Statement and the Rotorua Geothermal Regional Plan. Please contact our Consents Team if you would like to discuss this further.

Applying for resource consent

If you would like to apply to drill a bore in the Rotorua geothermal field please fill out the Bore Form.
If you would like to apply to take fluid or energy please fill out the Base Form and Form 6.
At this time new consents to take fluid or energy cannot be granted for sites within 1.5km of the Pohutu Geyser (the Mass Abstraction Exclusion Zone), if you are uncertain if this is includes your site please contact the Consents Team to discuss further.

Monitoring Programme

There are currently eight geothermal monitoring bores and five groundwater bores forming part of a geothermal monitoring program for Rotorua. For surface feature geothermal activity we regularly monitor Whakarewarewa southern springs and geysers; Ngapuna and Government Gardens; Kuirau Park and Ohinemutu.

Summary of work undertaken:

Physical aspects of the Rotorua Geothermal Field

Vegetation Features
Geological Features
Structural features
Hydrological features
Chemical characteristics

Aquifer Monitoring

Water level and Pressure
Temperature profiles
Geothermal monitoring bore
Groundwater monitoring bores

Surface feature activity

Surface features of the Rotorua Field
Monitoring of surface features
Southern springs and geysers
Ngapuna and Government Gardens
Kuirau Park and Ohinemutu
Hydrothermal Eruptions
Assessment of events since bore closure
Gas compositions
Interpretation of chemical change of system over time
Interpretation of pressure and flow change of system over time
Inputs and outputs (flow and temperature) of the system

Resource assessment and management

Interpretation of bore usage changes on system over time
Record bore ownership and information
Total withdrawal
Net mass withdrawal
Reinjection
Heat exchanger
Direction of use

Modelling

Development of conceptual model for Rotorua Field
Scenario modelling
Geological mapping
Thermal mapping
Collation and reporting of data
Reports

Kawerau Geothermal System

The Kawerau Geothermal field has hot springs, seepages, steaming and hot ground, and temperatures from deep bores is up to 250-315 °C. This is the only geothermal field in the Bay of Plenty Region that is currently being used to produce electricity. It is also the largest source of geothermal energy for direct use in the world.

The use of the geothermal field is an intrinsic part of the unique character of the picturesque town of Kawerau, the plumes of steam are visible from across the Rangitaiki Plains and if you enter from the north-east (heading from Whakatane to Kawerau) you will see the large pipes carrying geothermal fluid.

Planning provisions

Using fluid or energy from any other geothermal field will be considered under the Regional Policy Statement, the Regional Water and Land Plan, and the Regional Plan for the Tarawera River Catchment. Provisions of the Regional Air Plan may also apply. Please contact our Consents Team if you would like to discuss this further.

Low Temperature Geothermal Systems

There are a number of a low temperature systems (30-70 °C) in the Bay of Plenty region with few or no geothermal surface features. Water taken from within the field is often used to provide under floor heating or for swimming pools.

Examples of these systems are;

  • Tauranga/Mount Maunganui (including Te Puna and Athenree)
  • Pāpāmoa/Maketū
  • Awakeri
  • Matatā

Planning provisions

Using fluid or energy from any other geothermal field will be considered under the Regional Policy Statement and the Regional Water and Land Plan. Provisions of the Regional Air Plan, the Regional Plan for the Tarawera Catchment, and the Regional Coastal Environment Plan may also apply. Please contact our Consents Team if you would like to discuss this further.

Other Geothermal Fields

The Taupo Volcanic Zone crosses through the Bay of Plenty and gives us our many geothermal fields which all have a wide variety of values. The identified fields are;

  • Waimangu/Rotomahana/Tarawera
  • Whakaari/White Island
  • Moutohora/ Whale Island
  • Rotoiti
  • Rotokawa/Mokoia
  • Tikitere/Ruahine
  • Taheke
  • Rotoma/Tikorangi
  • Rotoma/Puhi Puhi

Planning provisions

Using fluid or energy from any other geothermal field will be considered under the Regional Policy Statement and the Regional Water and Land Plan. Provisions of the Regional Air Plan, the Regional Coastal Environment Plan and the Regional Plan for the Tarawera River Catchment may also apply.Please contact our Consents Team if you would like to discuss this further.

Geothermal Glossary

Bore - Any structure, well or hole in the ground, which is drilled or constructed. This includes bores that access underground resources (such as groundwater, geothermal water or geothermal heat) and those not accessing underground resources (such as monitoring or geotechnical bores).

Downhole Heat Exchanger - A device installed down a bore to remove heat from a geothermal field without removing geothermal fluid. Generally uses freshwater circulate through a heat exchanger at depth.

Freshwater -  All water, excluding coastal water, that is under 30 degrees Celsius.

Geothermal energy - Energy derived or derivable from and produced within the earth by natural heat phenomenon; and includes all geothermal water (Resource Management Act 1991).

Geothermal field -  An discrete area where geothermal energy is known to be found, and includes all areas that are hydrologically linked.

Geothermal fluid - Combined geothermal water and steam, undifferentiated proportions of either state, or a system that utilised both steam and water.

Geothermal surface feature - Includes, but is not limited to; mud pools, sinters, hot springs, hot pools, rogue bores, fumeroles, tomos, geysers, geothermally influenced freshwater systems, steam vents and areas of hot ground. Surface features may or may not be of natural origin, and includes extinct or intermittent features.

Geothermal water  - Water heated within the earth by natural phenomenon to a temperature of 30 degrees Celsius or more; and includes all steam, water, and water vapour, and every mixture of all or any of them that has been heated by natural phenomenon.

Reinjection - Geothermal fluid being pumped back into the ground to the same aquifer from which it was sourced.

Downhole heat exchanger - A single bore system which results in no geothermal fluid being abstracted from the bore.