The paper describes the history of the work at Kamojang from the start of the original investigations in 1971, through the exploratory drilling phase, preparation of the feasibility study, the production drilling phase, preparation of the feasibility study, the production drilling programme from 1976 to 1979, and development of the steamfield and power programme from 1976 to 1979, and development of the steamfield and power station from 1979 to 1982.
Details of both the exploration and production drilling programmes are given along with a brief description of the reservoir model. The major aspects of the design and construction of both the station and steamfield and associated works are summarized. Problems and progress to date are covered briefly. Environmental studies carried out are described. Finally, the nature of the operation and management of the station, g being carried out will prospect of possible future development at Kamojang and elsewhere are given.
The Kawah Kamojang geothermal field is located 42 km south east of Bandung in West Java, on the Gandapura-Guntur volcano complex. The field is at an elevation of about 1500 metres above MSL and lies between the rural centres of Majalya and Garut (See Map 1).
The first stage development is of a 30 MW capacity power station, with the electricity to be fed into the overall West Java 150 kV grid. Some 43 MW(e) of steam, available from 6 wells, will be connected to the power station. Recent drilling of 2 more wells has brought in a further 15 MW(e) of steam and exploratory drilling is continuing at a slow rate. Extensions in two stages to bring the station's ultimate capacity to between 90–140 MW are currently being considered.
As at the end of 1981, construction of the first 30 MW stage is well advanced with civil works on the station buildings being largely completed, mechanical and electrical installations underway and the steam transmission system nearly three quarters completed. This first unit is due to go into commercial operation in November 1982.
The project is being carried out under a bilateral agreement between the Indonesian and New Zealand Governments, with major grant funding being made by New Zealand under the Colombo Plan. The Indonesian Government input is provided by Pertamina (for the steamfield), Perusahaan Umum Listrik Negara (PLN) (for the power station) and the Vulcanological Survey of Indonesia (VSI) (for scientific matters). Geothermal Energy New Zealand Ltd. (GENZL) is the executing agency for the New Zealand Government and with the above agencies has carried out all the scientific investigations and reservoir assessment, supervised the drilling, designed the power station and is managing the construction of all the works. A major aim of the project is the transfer of technology and training of counterparts in all aspects of geothermal technology from exploration right through to station operation and management.
As early as 1918 proposals were made to exploit geothermal energy at Kamojang but it was not until 1926-28 that five shallow exploration wells were drilled by the Netherlands East Indies Vulcanological Survey. One of these wells, Kamojang 3, is still discharging superheated steam from a depth of 66 metres with a temperature of 140 degrees C and a pressure of 3.5–4 Bars abs. In 1972 after a joint reconnaissance programme between the New Zealand and Indonesian Governments of a number of geothermal fields on Java, Bali, Sulawesi, Sumatera and elsewhere, Kamojang was accorded the highest priority for further scientific investigation. A prefeasibility study of the Kawah Kamojang area was commenced by GENZL in September 1972. The detailed geophysical, geological and geochemical studies carried out delineated a possible geothermal field, about 14 square kilometres in area, of high potential. Following the signing of a formal agreement between the two Governments an exploratory drilling programme of five small diameter, medium depth, wells was carried out in the period from September 1974 to August 1975. Two of the five wells successfully discharged and all gave positive temperature indications. One well, Kmj 6, in fact, supplies dry saturated steam to a small 250 kVA monobloc generator which provides electrical energy to Pertamina's facilities at Kamojang. The results of these preliminary investigations were summarized in a major preliminary investigations were summarized in a major feasibility report published in November 1976. This report concluded that even using conservative assumptions, the reservoir was capable of supporting between about 100-200 MW of electrical power over a 25 year period, certainly enough to justify a programme of drilling and development aimed at the installation of programme of drilling and development aimed at the installation of a 30 MW power station as the first stage of a much larger future development.
This recommendation was accepted and a joint development programme was agreed upon between the Indonesian and New programme was agreed upon between the Indonesian and New Zealand Governments. A grant contribution of $24 million from New Zealand was promised. In September 1976 the first production well, Kmj 11, was spudded in. While drilling continued, design production well, Kmj 11, was spudded in. While drilling continued, design of the power station went ahead. By August 1979 production drilling was essentially completed but due to changes in funding arrangements between the Governments, on site construction of the power station itself only really got fully underway in April 1980 power station itself only really got fully underway in April 1980 with commissioning now due in late 1982.