New Zealand’s renewable geothermal resources

Chris Bromley, GNS Science

2014 Hochstetter Lecture and the RSNZ Manawatu August 2014 meeting – joint with the Geoscience Society of New Zealand 

7.30 pm Tuesday, 26 August, Te Manawa – Art Gallery, 326 Main Street, Palmerston North

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 electricity and industrial heat demands. Decades of well-focussed applied research have 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 surplus cheap geothermal power in the hopes of exporting it to Australia by cable or fully electrifying our transport sector? Or should we develop our 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 will not cause unwanted adverse environmental effects, or detract from our significant geothermal tourism assets. This requires more-advanced monitoring and better modelling 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 pressure, temperature and fluid chemistry. Geophysics monitoring and exploration offer more indirect information on resources. Integrated interpretation of these data with information on geochemical and hydrothermal processes is the key to better conceptual understanding, improved simulation models of reservoir behaviour, and more astute reservoir management.

 All warmly welcome