In early 2017 the Indonesian government introduced a new ceiling tariff for all renewable energy generation, including geothermal. Geothermal ceiling tariffs are now linked to the annual Average Generation Costs (BPP for its Indonesian abbreviation) for each electrical island/(sub)grid. This will result in very low ceiling tariffs in the main island grids (Java, Bali, and Sumatera) due to the dominance of cheap coal generation. The smaller grids of East Nusa Tenggara and Moluccas have much higher BPPs because these are dominated by diesel-generation ( although diesel prices are relatively low at the moment). This study examines how the current tariff regime relates to potential geothermal project costs in East Nusa Tenggara and Moluccas regions. It also explores what might influence future BPPs to provide some insight for future economic feasibility of geothermal power plants in these regions. As background, first the new geothermal tariff regulations are discussed, as well as Indonesia’s Geothermal Roadmap 2017-2026 and the latest Electricity Power Supply Business Plan (RUPTL) by the State Electricity Company PLN. To estimate geothermal project costs, a Geothermal Production Cost Model (GPCM) is used that was originally developed under sponsorship of both the Government of Indonesia and New Zealand. Subsequently, some key parameters are varied in a sensitivity analysis to have a preliminary look at policy options which could support the feasibility of geothermal projects. Finally, the future BPPs are estimated for East Nusa Tenggara and Moluccas, by analysing the component cost of BPP and its relationship to future oil prices.