Optimizing Financial Feasibility and Resource Utilization in Binary Geothermal Systems: A Case Study from the Dieng Geothermal Field, Indonesia

Abstract

This study evaluates the technical and financial feasibility of developing a binary geothermal power plant by utilizing residual brine from the Dieng geothermal field in Central Java, Indonesia. As one of the most geologically complex and active regions in Southeast Asia, the Dieng field represents significant untapped potential for secondary energy through binary cycle technology. By using data from reservoir simulation, brine chemistry analysis, and economic modeling, the study examines multiple development configurations across several scenarios. Technically, the study finds that several wells will have sufficient brine temperature and sustainability for the project, although there is a risk of silica content, which poses a scaling problem. Finally, the base scenario of the financial project is not viable under the current tariffs of USD 6.23 cents/kWh but becomes attractive when paired with optimized tariffs and resource integration from Dieng Unit-2. The findings support the pathway for enhanced geothermal utilization in Indonesia, emphasizing the importance of flexible development strategies, regulatory alignment, and technological optimization to ensure long-term project viability.