Profesor

Proceedings World Geothermal Congress 2010 Bali, Indonesia, 25-29 April 2010

Construction and Operation of Kamojang Unit 4, the First Commercial Geothermal Power Plant Built, Owned and Operated by PT Pertamina Geothermal Energy
Mawardi Agani, Khairul Rozaq, Zainal I. Bachrun
PT. Pertamina Geothermal Energy – Area Kamojang, West Java, Indonesia mawardi@pgeindonesia.com,khrozaq@pgeindonesia.com, zibachrun@pgeindonesia.com

Keywords: geothermal power plant (GPP), zero venting, commercial operation date, capacity factor ABSTRACT PT Pertamina Geothermal Energy (PGE) is established in December 19, 2006 to deal with geothermal business in Indonesia. It carried on the role of PT Pertamina, a stateowned oil and gas company, in developing the geothermal energy in this country, starting in1976, then succeeded in supplying steam to the first commercial geothermal power plant (30 MW.) namely Kamojang Unit 1 in 1983. It was followed by Unit 2 and Unit 3, 55 MW capacities each, commissioned in 1987. These 140 MW total capacity power plants are owned and operated by Indonesia Power, a subsidiary company of PT PLN the state-owned electricity company. Since then, PT Pertamina is recognizedas an upstream player in geothermal energy development, to be precise: a steam seller geothermal company. It was ended in early 2008 when PGE successfully commissioned a Geothermal Power Plant (GPP) namely Kamojang Unit 4. This 63 MW installed capacity geothermal power plant is the first large-scale geothermal power plant built, owned and operated by PGE, and will be a starting point to installand operate a total of 500 MW geothermal power plants in the next 3 years. The geothermal power plant had a starting commercial operation date (COD) on January 26, 2008, following a successful commissioning conducted at the end of the 2 year construction period. The basis of design is to acquire a lowest cost for every kW (net) installed capacity by conducting an optimization study of thecirculating water system. The zero venting principle is applied to eliminate the steam loss through the rock muffler during normal operation. The geothermal power plant consumes about 423 ton/hr of steam which originated from 8 production wells to produce 60.5 MW (net) of electrical power. Initially, only 7 wells are used to supply steam to the geothermal power plant, however due to decline in steamproduction, one additional well was put in on June 2008. On the other hand, Non Condensable Gas (NCG) content in steam declined from 1.9% to 0.85% wt which allows operating only one Vacuum Pump. Despite problems that occurred during the first year operation, the geothermal power plant was able to dispatch 471 GWh of electricity to the National Grid, equivalent to a capacity factor of 95.78%. 1.INTRODUCTION Kamojang Geothermal Field is located in 40 km South East of Bandung and about 24 km North West of Garut at an elevation of about 1500 m above sea level. The ambient temperature is around 15°C - 20°C with an average rainfall of 2,885 mm annually. Early exploration in Kamojang was carried out by Dutch Colonials in 1926–1928 by drilling five shallow wells at 1

about 120 m depth. Until now,one of the wells namely Kmj3 is still discharging superheated steam to the atmosphere. In 1971–1972, a prefeasibility study was conducted by Geothermal Survey of Indonesia (GSI) collaborating with the New Zealand Government. It was followed by geology, geophysics and geochemistry surveys which were conducted together by Pertamina and ENEX-GSI. In 1974, Government of Indonesia granted Pertamina, astate-owned company, the right to develop geothermal energy in Indonesia. Therefore, again under New Zealand government aid, Pertamina drilled the first exploration well on September 22, 1974 and by 1979 five exploration wells and ten production wells had been drilled (Suryadarma et al., 2005). On November 27, 1978, a 250 kW Monoblok was inaugurated by the Ministry of Mines and Energy to be the...