New exploration into geothermal potential underway
Friday, 16 October 2015 2:00 p.m.
A research project looking at the potential for hidden deep geothermal resources outside the known geothermal fields is currently underway east of Rotorua.
The project is being undertaken by GNS Science in partnership with the Bay of Plenty Regional Council and involves the collection of magnetotelluric (MT) data to extend existing data coverage centered on Rotorua. The aim of the research is to improve the understanding of the deep (3 to7 km) geothermal resource potential in the wider region, including the Okataina Volcanic Centre.
The current work is focused on the area east of Lake Rotorua and is the second stage of a larger research project involving GNS Science researchers based in Wellington that will take place over the next three or four years.
According to GNS Science geophysicist Grant Caldwell the initial results of the research are already proving to be extremely interesting.
“Over the last few years we have started to see the connection between the shallow parts of geothermal fields and the underlying volcanic systems which provide the heat.
“Results from Rotorua to date and similar research north of Wairakei have enabled us to start to understand how geothermal systems like Rotorua work from tip to toe – from the surface features down to their volcanic roots.
“As a Crown Research Institute, our job is to provide baseline information that could then stimulate future development. It’s been a tremendous help for us to have the additional support from the Regional Council for this research.”
Bay of Plenty Regional Council group manager strategic development, Fiona McTavish, says as managers of the resource, it is important this type of work is undertaken.
“Geothermal is recognised as an important asset for the Bay of Plenty region, offering potential to grow the region’s economy and social communities. We want to ensure we are utilising the resource as effectively and efficiently as possible for its long-term sustainability, as well as the future development of the region.
“This work is part of that goal – to understand more about different geothermal systems, their capabilities and potential. With careful management, the resource has capacity for growth in some areas and will continue to provide geothermal energy indefinitely. However, if too much is taken from a system it could be severely damaged.”
The research project is part of GNS Science’s Crown funded research with additional funding and support from the Regional Council.
- Magnetotellurics or MT for short, utilise very-small, natural-occurring fluctuations in the earth’s magnetic field to create a 3D image of the electrical conductivity (or resistivity) of the rocks deep beneath the earth’s surface.
- The electrical conductivity of a rock largely depends on the nature of the fluids trapped in the gaps between the mineral grains making up the rock.
- Rocks that contain geothermal fluids or that are partially molten are much more conductive than normal rocks.