Potency of Non Volcanic Hosted Geothermal Resources in Sulawesi-Indonesia

Abstract

Indonesia is blessed with abundant geothermal resources (27.7 GWe) that allow the country to lead the world with the the largest geothermal energy potential. About 96% (26.5 GWe) of the total Indonesian geothermal potencial is derived from a volcanic environment, while 4% (1.2 GWe) came from non volcanic environment., such as in Bangka, Kalimantan, Sulawesi (except N.Sulawesi and Gorontalo), and Irianjaya. Sulawesi has 46 promising locations in its geothermal field with a geothermal energy potential of 2134 MWe, unfortunately none of them have been developed as a geothermal power supply. Over the course of five years, the Geological Agency of Indonesia did an integrated study (geology, geochemistry and geophysical) in several areas of non volcanic geothermal propects in Sulawesi, such as Merana, Pulu-Pakuli, Parara, Masepe and Mangolo. We concluded that the geothermal systems in the area are anticipated to merge from varieties of tectonic phenomena such intrusive rocks (plutonics? and or concealed volcanic intrusive body?), which is associated with the NW-SE trending fault (Palu-Koro). The surface temperature varies from 40 – 90oC while the sub surface temperature ranges from 136 – 225oC. The potential of each non volcanic geothermal prospect is relatively small (10 – 80 MWe) compared to volcanic ones (up to 600 MWe), so small scale geothermal plants using binary system are considered more suitble for developing a non volcanic hosted geothermal prospect in Sulawesi Indonesia.