Evaluation and ranking of the CO₂ storage potential in low to medium temperature geothermal fields in Indonesia

Carbon capture and storage (CCS) is considered as a solution for achieving CO₂ emission reduction targets in Indonesia. On a commercial scale, geological carbon storage (GCS) systems have significant capital costs and energy penalties that the production of geothermal energy could somewhat compensate it. Coupling geothermal energy and geologic CO₂ storage in sedimentary basins is promising because of their large CO₂ storage capacities. The finding of this preliminary assessment indicates the attractiveness of combining CO₂ sequestration and geothermal utilization in low to medium temperature geothermal fields. The crucial criteria of this evaluation are the geothermal gradient, maturity, tectonic setting, geology, and hydrogeology. Due to their favorable tectonic conditions (rift valley), minimal faulting and fracture, and lack of active faults, the presence of geological structures are very minimal, leading to the conclusion that they are suitable for storing CO₂. There is no prior research has specifically identified the suitability of low to medium temperature geothermal fields in Indonesia to be combined with CO₂ storage, a rank of locations based on the suitability as CO₂ storage, and its utilization. The output of this study is an indicative map of low- to medium-temperature geothermal fields for CO₂ storage. It brings up new possibilities for using low to medium temperature geothermal fields as geological CO₂ storage in addition to hydrocarbon reservoirs, CBM, and deep saline water.