New Zealand’s renewable geothermal resources

Royal Society Hochstetter Lecture
Wednesday 27 August 7:30 pm. Holt Planetarium, Chambers St, Napier

ChrisBromleyChris Bromley is a senior geothermal researcher and geophysical consultant at GNS Science, with 35 years of international experience, including resource assessments, geophysical exploration, and environmental studies of geothermal fields and mineral deposits in 8 countries.

Chris is currently the Co-Editor-in-Chief of Geothermics, Chairman of the IEA Geothermal Implementing Agreement, a member of the IPGT Induced Seismicity Working Group, and heads international geothermal environmental-effects research.

New Zealand’s renewable geothermal resources

Renewable energy will be crucial for the long-term future of all mankind. In New Zealand, we are relatively fortunate, in that renewable geothermal energy is already a major contributor (18%) to base-load electricity supply and industrial direct heat demand. Decades of well-focussed applied research has given us a global technological advantage in developing and utilising all types of geothermal resources, through cost-effective and environmentally benign strategies.

Gazing into the crystal ball, what additional future use could we make of our geothermal resources? Should we attempt to develop say 3 GW(e) of surplus cheap geothermal power in the hopes of exporting it to Australia by cable or fully electrifying our transport sector, or  should we develop say 10 GW(th) of hot water resources to establish large district heating schemes and attract more energy intensive industry?

To address these questions we need to be confident that our geothermal resource use will be sustainable, and utilisation won’t cause unwanted adverse environmental effects, or detract from our significant geothermal tourism assets. This requires better calibrated simulation modelling of long-term reservoir behaviour, adaptive management to facilitate flexible injection and production strategies, and more-advanced monitoring of reservoir behaviour in order to inform the adaptive decision-making process.

Boreholes provide data for 3D models of reservoir properties, and a means of directly monitoring various parameters of interest (eg. pressure, temperature, fluid chemistry). Geophysics monitoring and exploration (eg. gravity, resistivity, micro-earthquake activity, seismic velocity tomography, and ground deformation) offer more indirect information on resources. Integrated interpretation with geochemistry and hydrothermal alteration processes is the key to better conceptual understanding, improved simulation models of reservoir behaviour, and more astute reservoir management.

Download a pdf of Abstracts here>

More about Chris Bromley

Chris Bromley was a lead author of the geothermal chapter of the IPCC renewable energy report (SRREN), a reviewer of EGS projects for the US-DOE, and keynote/invited speaker at 14 international meetings.

In New Zealand, he peer reviews operational management of several geothermal fields and provides technical advice to regulators. He has published 88 refereed papers, 103 others, and 184 consulting reports; he has presented at 73 conferences, and convened five international workshops on induced seismicity, sustainability, global geothermal potential, geothermal innovation and environmental mitigation.

For information about Ferdinand Hochstetter, see the Geoscience Society of New Zealand site.

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