Project Development Update of the Dieng Unit-2 Geothermal Power Plant, Dieng Geothermal Field, Indonesia

Abstract

The Commercial Operation Date (COD) for Dieng Powerplant Unit-1, operated by PT. Geo Dipa Energi (Persero), was in 2002 with installed capacity 1x55 MW. First well for Dieng Unit-1 drilled back in 1975 and ended in 1998. Dieng is a liquid dominated geothermal field with relatively deep and high temperature reservoir. The main reservoir temperature ranges from 300-330oC and located around 500-(-500) mASL. The highly productive reservoir in the Dieng area has been providing two-phase fluids with low non-condensable gas content. Dieng Unit-2 is Dieng Unit-1 expansion, aims to obtain capacity of approximately 55+10% buffer MWe. The development plan will be concentrated in the Sileri area with early estimation of at least 6.2 square-kilometers proven area. The plan has been designed to achieve maximum steam availability, adequate injection capacity, and optimum long-term reservoir performance. The plan includes drilling a total of 10 wells, consist of 5 production wells and 5 injection wells. The last well for Unit-2 is drilled in August 2023, with success ratio 100% target achieved. The drilling campaign result has been extending the proven area to 11.7 square-kilometers.