Lessons Learned from Kamojang Geothermal Steam Field Management: from the Beginning Until Now

Abstract

Kamojang is the first geothermal field in Indonesia, and it is known as one of the vapor-dominated systems of the world. It was first producing steam in 1978 to generate electricity for its own use through a 250 KW mono-block unit. The first commercial operations of 30 MW started in 1982. Subsequently, an additional 110 MW started commercial operations in 1987. A new 60 MW unit entered commercial operation in January 2008. In addition, the possibility of having another 60 MW unit is now being evaluated. The current rate of mass withdrawal shows the imbalance of discharge and recharge induces decreases of water level to deeper parts of the reservoir. Also, the 25 years of continuous commercial production have led to slight declines in the reservoir pressure and temperature within the active production sector. As a result, some of the 33 production wells show slight production decline and tend to approach superheated conditions. The reinjection programme, may have slowed down these phenomena, and especially that of the reservoir being superheated. The present state of the field is characterized by the increase from 140 MW to about 200 MW commercial operations in the early part of 2008. Thus, the increase of withdrawal rate might affect the Kamojang reservoir and energy production unless the right steam field management strategies are applied.