An impact assessment and decision support tool for geothermal projects in Aotearoa

In Aotearoa, geothermal resource management requires assessing sustainability trends across environmental, cultural, social, and economic dimensions, as mandated by legislation. While triple-bottom-line approaches are well-established for evaluating environmental, social, and economic impacts, cultural impacts are typically assessed separately. This report introduces a novel decision-support tool that integrates all four dimensions, offering a comprehensive quadruple-bottom-line impact assessment specifically for the geothermal industry. The tool adapts the Mauri Model Decision Making Framework, traditionally used for engineering projects, by identifying a transferable set of indicators tailored to geothermal developments in the Central North Island. The tool was developed through a combination of mātauranga Māori and Western knowledge, employing diverse research methodologies. Cultural indicators and thresholds were informed by over 16 h of wānanga (collaborative workshops) with Māori participants and augmented by literature reviews, as detailed in Taute, Morgan ( Taute et al., 2022 ; Taute et al., 2023 ). Environmental, social, and economic indicators were developed through participatory action research, including consultations with 14 industry professionals from organisations such as GNS Science, the New Zealand Geothermal Association, and major geothermal companies. Over 500 potential indicators were reviewed, with expert feedback refining the final indicator set and thresholds for industry alignment. The final set contained 112 indicators with thresholds. This tool ensures that cultural impacts are systematically evaluated together with conventional sustainability metrics, addressing a critical gap in geothermal impact assessments. It offers a robust framework for holistic decision-making in geothermal resource management. • A novel decision-support tool integrates cultural, environmental, social, and economic impacts. • The tool adapts the Mauri Model for geothermal project sustainability assessments. • Over 500 sustainability indicators were reviewed and refined through expert engagement. • A quadruple-bottom-line approach ensures cultural impacts are assessed alongside others. • Worldview sensitivity analysis quantifies stakeholder perspectives on sustainability.