Geothermal: The Next Generation

Our research will find and characterise New Zealand’s supercritical resources in support of future exploration, drilling and technology development.

Overview

Geothermal: The Next Generation is an MBIE research programme led by Dr Isabelle Chambefort from GNS Science. To provide sustainable, low-carbon energy for future generations, exploration of the Earth’s energy must move towards hotter and deeper supercritical heat reserves (4 km to 10 km).

This programme aims to

  • locate the best areas for exploration and map their potential
  • locate the best areas for exploration and map their potential
  • train and inspire the ‘next generation' of scientific leaders in this field
  • translate the science, making information clear and accessible
  • fundamentally transform Aotearoa New Zealand’s energy sector by offering a more eco-friendly, decarbonised energy system

To achieve these objectives, we will

  • draw on the learnings of supercritical heat exploration worldwide (e.g. Japan and Iceland)
  • explore for the best location to encounter supercritical fluids in the crust
  • define heat transfer systems from magma (molten underground rock) to surface
  • model how to go beyond traditional geothermal systems and tap into deeper heat resources known as supercritical (fluid compressed beyond its critical pressure and temperature point) and characterise their unique properties
  • provide a supercritical geothermal strategy for New Zealand

The project

Supercritical geothermal

We are working with international and New Zealand research and end-user collaborators to significantly increase the amount of energy produced from deeper and hotter geothermal resources in New Zealand. Scientists believe these resources could play a major role in the transformation of our energy sector.
Geothermal resources will be an important contributor to achieving the Government’s goal of net zero carbon emissions by 2050. This work will also open the way for investment opportunities and new employment, especially in industrial-scale use of energy.

Supported through MBIE’s Endeavour Fund, the project is aiming to find underground energy sources that are more than 100 degrees Celsius hotter than what is currently used in New Zealand (>400°C). One particular focus is the Taupō Volcanic Zone – the area between Lake Taupō and Whakatane – and the development and study of the distinct chemical characteristics of these underground environments.

Geothermal | Key to the Carbon Neutral Future transcript

Geothermal, key to the carbon neutral future.

Why is geothermal the key to a carbon neutral future?

Geothermal is a natural energy source that can be used to generate electricity. Geothermal systems are found in areas where there are lots of volcanoes.

In Aotearoa, New Zealand, most geothermal fields are found in the Taupō volcanic zone in the central North Island.

In this volcanic zone, CO2 is emitted naturally, let's look at this process.

Magma in the earth's crust heats water held in natural reservoirs. As the water heats, CO2 from the magma dissolves into the water.

When hot water rises, CO2 is released from the water.

Gas then escapes through hot pools, natural vents called fumaroles, or steam that escapes through the soil.

Gas that includes CO2.

So how can geothermal energy be carbon neutral? Let's examine how geothermal power plants work.

Water and steam are piped up from the geothermal reservoir under the ground.

Steam rotates the turbines.

A generator produces electricity, and then the water is injected back into the reservoir. This helps maintain pressure in the system.

When the water turns into steam, so do the gases, and at a geothermal power plant, even though the water is re-injected into the system, it may not include all the CO2. Some CO2 is released into the atmosphere. Scientists in the geothermal industry, including at GNS science are developing techniques to stop these gases escaping. It involves re-dissolving the CO2 in water then re-injecting it back into the reservoir.

Doing this helps maintain the geothermal system, while keeping the CO2 underground where it can't damage the environment.

Geothermal scientists are working towards a carbon neutral future.

Geothermal energy will give New Zealand energy security and help New Zealand reach its goals of 100% renewable energy, and net zero carbon emissions by 2050.

Geothermal | Key to the Carbon Neutral Future

Geothermal is a critical source of renewable energy for New Zealand. The question is, can geothermal energy be carbon neutral? To answer this, GNS scientists are developing techniques that prevent carbon dioxide emissions from geothermal power plants.

Addressing geological, geochemical and technological challenges

At present, conventional geothermal wells are drilled to a maximum depth of about 3.5 km. However, by drilling beyond this, possibly to 6 km, scientists believe more energy will be available at the surface for the same amount of geothermal fluid extracted. The extreme physical and chemical conditions at deeper levels make it a challenging engineering operation.

The project aims to identify the best areas for exploratory drilling. It is also exploring the potential for re-injecting carbon dioxide produced as a result, to enable emissions-free ‘deep heat’ energy.

Laboratory simulations will be used to see how these very hot fluids react with rock, and how their use will affect deep reservoirs and neighbouring shallower reservoirs.

Alongside this work, our experts will evaluate how these deep resources might best be managed under legislative and planning frameworks. The project team is planning significant consultation and engagement with Māori, central and local government, and industry as the project develops. We are also communicating in general about geothermal to increase the awareness around this renewable energy source.

Deep or very hot geothermal initiatives are also underway in several other countries – notably Japan, Italy, Iceland, and the United States. However, so far no one has managed to successfully harness the very hot geothermal resources from these depths.

Deep geothermal generation will only go ahead in New Zealand when there is confidence that it can be done safely, sustainably, and economically. There is more information at: www.geothermalnextgeneration.com(external link)

  • Publications

    For the publication list and links refer to: https://www.geothermalnextgeneration.com/knowledge

Research project details

Collaborators: University of Auckland, Victoria University of Wellington, the ETH-Zurich in Switzerland as well as planners from Traverse Environment Limited, Bridger Limited and Upflow.

Duration

2019–2024

Funding platform

GNG Programme

Status

Current

Programme Leader

Dr Isabelle Chambefort

Funder

Ministry of Business, Innovation & Employment (MBIE)

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