Result of the preliminary geological investigation of natural steam fields in Indonesia

Abstract

To meet the rising demand of electricity, the Indonesian Government has been forced to look for different sources of energy beside the hitherto known « conventional ones å. Since the Indonesian Island Arc is extremely volcanic, development of geothermal powerplants might provide the solution for the electrification of the rural areas. In the broad context of the recently launched Indonesian Five Year Plan, the Institute of Power Research in Jakarta, with the cooperation of the Bandung Institute of Technology, has started with a systematic investigation and geological mapping of the known existing steam fields. In 1968, several spots in Java have been singled out for closer investigation: four of these have been considered potentially favorable. These are the Dieng volcanic mountains in central Java, Mt. Tampomas and surroundings, the solfataric field of Kawah Kamodjang and the Hot Spring area of Tjisolok in western Java. Except for the solfataric field of Kawah Kamodjang, geological conditions of the other fields, structural as well as stratigraphical, are found to be promising. In these areas, a thick sedimentary series of Tertiary age ranging from sandstones to shales and marls which can play the role of reservoir and cap rocks, were intruded by magmatic stocks during the last phases of volcanism in Java. Besides, these areas are dissected by young faults which might lead to the formation of commercial steam-traps.