| Title | Sustainable Geothermal Utilization Deduced from Mass Balance Estimation - A Case Study of Kamojang Geothermal Field, Indonesia- |
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| Authors | Yayan Sofyan, Yunus Daud, Yustin Kamah and Sachio Ehara |
| Year | 2010 |
| Conference | World Geothermal Congress |
| Keywords | Sustainability, mass balance, gravity change, Kamojang Geothermal Field |
| Abstract | Geothermal energy is renewable energy, that is, the energy removed from the geothermal reservoir is continuously replaced on time scales similar to those required for energy removal. Energy supplied to the geothermal reservoir comes from natural recharge and injection. Sustainable production in the geothermal energy development is the ability of the production system applied to sustain the stable production level over long times. It is very important to manage the mass balance between production, injection and natural recharge in the geothermal reservoir during exploitation. The Kamojang Geothermal Field in West Java is the oldest developed geothermal field in Indonesia. It is a vapor dominated system and its installed capacity is 200 MWe. More than 116.78 x 106 tons of steam has been exploited from KGF since 1983 to 2000. We estimated the mass balance in the geothermal reservoir based on the repeat gravity measurement. From two calculations in different times, we estimated that the rate of natural recharge is almost same, that is, 2.77 Mt/year. However the recharged energy is smaller than the produced one has influence to the decline of steam flow rate of Kamojang production wells. Increasing injection rate and/or decreasing production rate are necessary to maintain sustainable production in KGF. |