Heat from within the earth, brought to the earth’s surface as liquid or steam, forms the basis of geothermal electricity production. When extraction rates are kept at sustainable levels geothermal power plants should be able to support the electricity needs of multiple generations. This chapter offers insight into some of the legal and technical questions surrounding the sustainability of geothermal energy in Aotearoa New Zealand and beyond. The chapter also explores the relationship Māori, New Zealand’s indigenous people, have with geothermal. Finally, the regional importance of New Zealand’s geothermal industry is considered—since New Zealand has been very influential in supporting geothermal energy development in Indonesia.