| Abstract |
The overview covers four decades between 1970 and 2010 and highlights exploration and developments of Indonesian geothermal prospects that began during the 1st decade with a US Aid study (Dieng 1970/1). It was followed by a NZ aid project with a survey of five prospects leading to exploration drilling at Kamojang and Darajat (1972/79). Indonesian counterpart organizations joined developments, involving VSI, PLN and Pertamina. Each group undertook surveys of new prospects and engaged already overseas consultants from France, Japan and Italy. A pilot plant (30 MWe) was under construction at Kamojang at the end of the 1st decade. At the start of the 2nd decade, a presidential decree allowed Pertamina to enter joint operation contracts (JOC) with local and international partners such as Unocal and Amoseas to develop the Salak and Darajat fields. Pertamina started to use MT, airborne magnetic, soil gas, and T gradient surveys, mainly in Java, with variable success. VSI explored prospects in Sumatra and Sulawesi with drilling sponsored by Japanese Aid. Increasing overseas training was provided by Iceland, Italy and NZ. At the end of the 2nd decade, the installed power plant capacity was 140 MWe (Kamojang). At the beginning of the 3rd decade, ten JOCs were signed with Pertamina as counterpart. These contracts involved mainly US companies to develop 4 prospects in Sumatra, five in Java, and one in Bali (all signed in 1993/4). The developers undertook their own earth-science surveys. Accelerated drilling confirmed productive sectors outlined in part by new geophysical methods, e.g CSAMT, MAM, MEQ, and deep T gradient (cored) holes. Significant formal training was offered by Iceland, Japan, and NZ. All JOC projects came to a halt with the 1997 financial crisis. At the end of the 3rd decade, the installed total capacity of 4 geothermal plants was c. 530 MWe. A review of geothermal licensing occurred during the 4th decade. The Ministry (MEMR) together with regional governments were assigned the role of issuing new licenses (WKP) through a bidding and control process (Law 27/2003). This attracted private developers. Exploration of Banda Arc Islands projects involved mainly VSI and PLN groups. By the end of 2010, a total of c. 55 geothermal prospects had been explored by ground surveys and c. 20 prospects had been tested by deep exploratory drilling. The installed capacity of seven developed Indonesian geothermal fields had reached c. 1200 MWe by 2010. |