Underused geothermal potential in Southeast Asia’s net-zero transition

• Cross-disciplinary review of Southeast Asia geothermal potential. • Links resource endowment, deployment, and net-zero contributions. • Integrates subsurface risk, environmental impacts, and economics. • Highlights regulatory, risk-sharing, and finance barriers • Outlines policy and financing instruments for deployment. Geothermal energy offers firm, low-carbon power in Southeast Asia, yet deployment lags resource potential. This article synthesizes evidence from geoscience, engineering, and political economy to explain this gap. We argue that geothermal outcomes are governed less by “how much heat is underground” than by the translation of subsurface uncertainty into bankable projects under multi-agency permitting, forest and land-use rules, and community consent. Technically, project viability hinges on permeability creation and preservation, pressure–temperature drawdown, and induced-stress pathways that affect injectivity, well productivity, and long-run decline; economically, these geomechanical risks are front-loaded and largely sunk at the exploration stage. Institutionally, Indonesia and the Philippines illustrate how protected-area regulation, indigenous land rights, and the credibility of benefit-sharing and grievance processes shape timelines, renegotiation risk, and the cost of capital. Policy designs that jointly de-risk early drilling (public data, drilling support, blended finance), stabilize revenues (firm-resource procurement, contracts-for-difference), and make participation and rent allocation credible can materially lower financing frictions. We conclude with a research agenda to quantify governance bottlenecks using project-level timelines and to integrate them into real-options and credible-commitment models. The review emphasizes policy-relevant mechanisms rather than case narration, and outlines metrics for monitoring social risk alongside reservoir performance systematically.