Geothermal is vital for sustainable energy systems development in Indonesia. The country is privileged with estimated geothermal reserves equivalent to 29 Gigawatt-electric. However, harvesting such massive potential is precarious since geothermal projects are capital intensive, complex, and sensitive to uncertainties and risks - -thus, the projects become a less attractive investment. Moreover, due to deep uncertainties, difficult decisions often have to be made regarding geothermal projects (dis)continuation for financial reasons. Additional governance measures, such as sustainable financing, are required to ensure the viability of the projects in the long run. In order to address this concern, this study proposes a conceptual framework that can be used to develop a sustainable financing model for geothermal projects. Notably, the conceptual framework is developed for exploring alternative financing schemes that are robust and attractive when faced with uncertainties and risks during the projects. For this purpose, the study employs the exploratory system dynamics modeling and analysis (ESDMA) approach and introduces the exploratory financial modeling and analysis (EFMA) approach. ESDMA analyzes geothermal project complexity and explores robust policies under deep uncertainties, while EFMA analyzes the project's financial performance and explores robust-attractive financing schemes under deep uncertainties. Aligning the results from both approaches, a sustainable financing model for geothermal projects is formulated.