Geothermal in Indonesia

Geothermal Energy was first used for experiment power generation in Larderello, Italy on July 4 1904 by Prince Piero Ginori Conti. However commercial development followed slowly thereafter. The Larderello site also saw the first commercial geothermal power plant 250 kW in 1913 as well as the first large power installation in 1938 is 69 MW.


Potential of geothermal energy in Indonesia is 19.600 MW or 40% of potential in the world, but just now only 5% use it. Why…? The high cost of investment and low electric capacity are the problem. For example 20 MW Lahendong Unit 2 Geothermal Power Station has cost $ 28 Million. Now 20 MW Lahendong Unit 3 Geothermal Power station is under contruction, and will Supply 10.000 house in North Celebes Lahendong country. It would be come the biggest gift for them.


Indonesia is richly endowed with both dry-steam and hot water geothermal resources associated with numerous active volcanoes all along 7.000 km long plate boundary with the Indo-Australian plate to its south. Both convergent as well as strike-slip movement along the plate boundary is believed to have caused large concentration of high temperature geothermal system close to the plate margins in Sumatra, Java, South-East land, Celebes and Halmahera.
At least 70 high-enthalpy geothermal field have already been identified, of which 7 are under production


The producing fields in Java islands are predominantly steam fields whereas these Sumatra and Celebes are hot water fields. The total installed capacity is estimated at about 807 MW, with additional capacities planned in the near future. However, further exploration and development program would be required to utilize the vast geothermal energy potential available in the country, and contribute to its rapidly growing energy needs. Very few direct uses of geothermal energy are practiced in Indonesia.

Electricity generation mainly takes place in conventional steam turbines and binary plants, depending on the characteristics of the geothermal resource.



Conventional steam turbines require fluids at temperatures of at least 150 °C and are available with either atmospheric (back-pressure) or condensing exhausts. Atmospheric exhaust turbines are simpler and cheaper. The steam, direct from dry steam wells or, after separation, from wet wells, is passed through a turbine and exhausted to the atmosphere



With this type of unit, steam consumption (from the same inlet pressure) per kilowatt-hour produced is almost double that of a condensing unit. However, the atmospheric exhaust turbines are extremely useful as pilot plants, stand-by plants, in the case of small supplies from isolated wells, and for generating electricity from test wells during field development. They are also used when the steam has a high non-condensable gas content (>12% in weight). The atmospheric exhaust units can be constructed and installed very quickly and put into operation in little more than 13-14 months from their order date. This type of machine is usually available in small sizes (2.5 - 5 MWe).
The condensing units, having more auxiliary equipment, are more complex than the atmospheric exhaust units and the bigger sizes can take twice as long to construct and install. The specific steam consumption of the condensing units is, however, about half that of the atmospheric exhaust units. Condensing plants of 55 - 60 MWe capacity are very common, but recently plants of 110 MWe have also been constructed and installed



Generating electricity from low-to-medium temperature geothermal fluids and from the waste hot waters coming from the separators in water - dominated geothermal fields has made considerable progress since improvements were made in binary fluid technology. The binary plants utilize a secondary working fluid, usually an organic fluid (typically n-pentane), that has a low boiling point and high vapour pressure at low temperatures when compared to steam. The secondary fluid is operated through a conventional Rankine cycle (ORC): the geothermal fluid yields heat to the secondary fluid through heat exchangers, in which this fluid is heated and vaporises; the vapour produced drives a normal axial flow turbine, is then cooled and condensed, and the cycle begins again











Comparison invest cost between fossil fuel and renewable energy can show table below. As describe, Fossil fuel needs 1030 - 1150 $/kW, Renewable energy needs 500 - 20,000 $/kW.

















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