A Review of Critical Element Concentrations in High Enthalpy Geothermal Fluids in New Zealand

Abstract

This review compiles publicly available datasets describing the chemical composition of geothermal fluids from eight wells in the Taupo Volcanic Zone (TVZ) and Ngāwhā, New Zealand. Our review allows previously reported geothermal reservoir water compositions at various locations around the TVZ (and Ngāwhā) to be assessed and compared for the first time. The combined data present a new perspective on potential critical elements of geothermal resources and will be a valuable tool for future research projects and investment opportunities. Composition data were used to estimate the annual flux of different elements in New Zealand geothermal systems. Several elements found in New Zealand geothermal fluids are currently considered ‘critical’ for the transition to a carbon-neutral economy and are present in economically extractable quantities. We estimate that each year, approximately 1100 tons of lithium pass as heat exchange fluids through Wairakei geothermal power station. An overview of the critical elemental capture and extractive potential from New Zealand’s geothermal fields is provided.