| Keywords |
low temperature geothermal, Southern Alps, New Zealand, West Coast Region, Alpine Fault, sedimentary basins, potential heat use, GIS analysis, geospatial prioritization |
| Abstract |
The North Island of New Zealand is renowned for its high temperature geothermal resources utilized for electricity generation, direct use applications and tourism. However, the South Island also has geothermal resources, albeit at lower temperatures, that manifest as warm springs at several locations within the mountainous Southern Alps. These are currently used for bathing, from non-commercial pools to tourist-level commercial developments. With the New Zealand Government encouraging regional development and use of renewable energy sources, local stakeholders of South Island West Coast Region are investing to assess and quantify the geothermal resources for potential use. The western Southern Alps are characterized by steep relief, high mountains and deep river valleys. The mountain ranges are densely vegetated, with remote and isolated areas covered in native forest. The area is sparsely populated with most settlements on the western side of the mountain range. Sedimentary basins west of the Alpine Fault also offer potential for heat use, albeit with lower temperatures and thermal gradients. While rich in coal resources, development of geothermal energy for direct heat use and small local electricity generation would secure local energy supplies and promote some economic development in the region. Two geothermal domains have been identified for the West Coast Region, that being the Alpine Fault domain and the Sedimentary Basin domain. Using the geological and structural characteristics from both, along with fluid flow estimates and heat source processes, as they are currently understood, geospatial analysis of each domain has identified the most prospective geothermal areas. With a focus on usability of the resource, other spatial parameters considered in the analysis include potential surface limitations, such as steep local topography, land-use, land-cover, land-ownership, conservation status, and distance to heat prospects. Energy demand estimates and supply temperature requirements are also important considered parameters. This paper shows how GIS geospatial analysis can be a useful tool for defining and prioritizing geothermal prospect areas. However, the analysis is underpinned by well developed geoscientific conceptual models, along with clear understandings of end-user energy requirements and surface infrastructure and land constraints. The preliminary investigation on the West Coast identified and substantiated possible utilization of low temperature ( |