The Eight Geothermal Operators in Indonesia

The Beginning

Indonesia is the second-largest geothermal energy producer in the world, after the US, with a total installed capacity of 2653 MW as of December 2024, according to ThinkGeoEnergy.

The story of geothermal energy in Indonesia began in 1918 when Dutchman JB Van Dijk noticed and reported the potential of geothermal energy in the Kamojang area of West Java.

Inspired by the successful geothermal development in Larderello in Italy, a Dutch company drilled five shallow wells between 60 and 128 meters deep from 1926 to 1927 in the Kamojang area. One of them, the well KMJ-3, was successful and is still producing steam today.

This discovery established the Kamojang area as having tremendous potential for geothermal energy development.

Subsequently, in 1974, Pertamina began exploring and assessing the geothermal resources in Kamojang in earnest with the cooperation of New Zealand.

Then in 1978, the first geothermal power station in Indonesia came into production at Kamojang with an installed capacity of 0.25 MW.

Today, the Kamojang power plant consists of 5 power stations with a total installed capacity of 235 MW, making it one of Indonesia’s biggest geothermal power plants.

Since the establishment of the Kamojang plant, many companies have started to develop geothermal resources in Java, Sumatra, and the Eastern part of Indonesia.

Here are the seven geothermal operators in Indonesia.

PERTAMINA GEOTHERMAL ENERGY

Pertamina Geothermal Energy is Indonesia’s first and most active geothermal company. It constructed the first geothermal plant in Indonesia, the Kamojang power plant in 1978 with the cooperation of New Zealand.

PGE operates and supplies steam to 21 geothermal power plants in six work areas, namely in Kamojang, Sibayak North Sumatra, Ulubelu, Lahendong, Lumut Balai South Sumatra, and Karaha West Java. The total installed capacity of the 22 power stations is 727 MW.

Besides these direct operations, PGE has joint operation contracts with several geothermal operators in the operation of their power plants with a total of 1205 MW installed capacity.

Pertamina Geothermal Energy became a public company on February 24, 2023. With the 594 million USD of fresh funds it received from the IPO, PGE plans to add 600 MW of installed capacity by 2029.

Here are the geothermal plants that PGE operates:
• 235 MW Kamojang Units 1, 2, 3, 4, 5 in West Java (Note: Supplying steam to Units 1, 2, and 3 operated by PLN)
• 120 MW Lahendong Units 1, 2, 3, 4, 5, 6 in Sulawesi
• .5 MW Lahendong Binary in Sulawesi
• 110 MW Ulubelu Units 1 and 2 in Lampung, Sumatra (Note: Supplying steam to PLN)
• 110 MW Ulubelu Units 3 and 4 in Lampung, Sumatra
• 110 MW Lumut Balai Unit 1 and Unit 2 in South Sumatra
• 30 MW Karaha Bodas in West Java
• 12 MW Sibayak Unit 1, 2, and 3 in North Sumatra

Upcoming Projects

Pertamina Geothermal Energy is intensifying its efforts to expand geothermal power generation capacity.

The company plans to add up to 215 MW of new capacity through the following projects:

– Lahendong Power Plant Units 7 and 8, each with a capacity of 20 MW, along with a 10 MW binary unit in North Sulawesi.

– Lumut Balai Units 3 and 4, each with a capacity of 55 MW, are located in South Sumatra.

– Ulubelu Extension 1 in the Gunung Tiga geothermal area in Lampung, which has a potential capacity of 55 MW.

These projects are targeted for completion by 2029.

Here are PGE’s other joint venture projects:

• PGE, Chevron, and Mubadala have agreed to conduct a joint study to explore the geothermal potential in Kotamobagu located in North Sulawesi.

• PGE and Chevron will spend 220 million USD to develop the Way Ratai geothermal work area in Lampung. The consortium aims to construct a 55-MW power plant by 2031.

STAR ENERGY GEOTHERMAL

Star Energy Geothermal was established in 2003. Its vision is to be the fastest-growing, most profitable, best-managed energy company in the region.

Star Energy, operating three geothermal power plants with a total installed capacity of 874 MW, is Indonesia’s largest geothermal energy producer.

Here are the three geothermal plants in which it operates.
• Salak plant (337 MW) in West Java – Acquired from Chevron in 2017
• Darajat plant (270 MW) in West Java – Acquired from Chevron in 2017
• Wayang Windu (227 MW) in West Java – Acquired from Magma Nusantara Limited in 2004

Current Projects
• Exploring the geothermal prospect in Gunung Hamiding, located in North Maluku.
• Exploration in Sekincau in Lampung, Sumatera

Here are the subsidiary companies of Star Energy Geothermal:
• Star Energy Geothermal Salak, Ltd.
• Star Energy Geothermal (Wayang Windu) Limited|
• Star Energy Geothermal Darajat II, Limited
• PT Star Energy Geothermal Suoh Sekincau

PT GEO DIPA ENERGY

Geo Dipa Energy was founded in 2002 by the Indonesian government to construct and operate the Dieng and Patuha geothermal power plants.

Managing two geothermal plants with a combined capacity of 125 MW, Geo Dipa Energy’s vision is to be a reliable and trusted geothermal company.

Here are the two plants that Geo Dipa Energy operates:
• 70 MW Dieng Unit 1 power plant located in Central Java.
• 55 MW Patuha Unit 1 power plant located in West Java.

Current Projects
• Dieng Unit 2 Development. Geodipa is drilling steam wells for the 55 MW Dieng Unit 2 power station project.
• Patuha 55 MW Unit 2 Development.
• Exploration in the Candradimuka work area.
• Exploration in the Arjuno Welirang work area.

KS ORKA RENEWABLES PTE LTD

KS Orka Renewables, established in 2015, manages and operates 5 geothermal stations and 2 power stations in North Sumatera and Flores respectively.

Its newest power plant, completed in December 2024, is the 33-MW Sorik Marapi Unit 5 in North Sumatra. PT Sorik Marapi Geothermal Power, the plant operator, started the plant commercially on December 16, 2023.

Here are the power plants that KS Orka Renewables operates:
• 220 MW Sorik Marapi geothermal plant in North Sumatra consisting of Units 1, 2, 3, 4, and 5 power stations.
• 5-MW Sokoria Unit 1 and 3-MW Unit 2 geothermal plants in Flores.

Current Projects:
• Exploration in the Samosir work area in North Sumatera

Here are the operating subsidiary companies of KS Orka Renewables:

1. PT Sorik Marapi Geothermal Power
2. PT Sokoria Geothermal Indonesia
3. PT Samosir Geothermal Power

PT SUPREME ENERGY

Supreme Energy was founded in 2007 under the leadership of Mr. Supramu Santosa, with Engie, Marubeni, and Tohoku Electric Company as joint venture partners. Its vision is to become the leading and most respected geothermal energy company, generating clean and sustainable electricity. Mr. Nisriyanto is the current President and CEO.

Supreme Energy operates three power stations in two work areas with a total installed capacity of 130 MW.

Here are the three power stations:
• The 45.6 MW Unit 1 and 45.6 MW Unit 2 stations in the Rantau Dedap work area in South Sumatera. . Based on the PPA (Power Purchase Agreement) with PLN, Supreme Energy Rantau Dedap has the potential to double its energy output to 220 MW.   

• The 85 MW Muara Laboh Unit 1 power plant in West Sumatera.

Current Projects
• Exploration in the Rajabasa work area
• Development of 75 MW Muara Laboh Unit 2 power station.

Here are the three subsidiary companies of Supreme Energy:

1. PT Supreme Energy Rantau Dedap
2. PT Supreme Energy Muara Laboh
3. PT Supreme Energy Rajabasa

SARULLA OPERATIONS LIMITED

Sarulla Operations Limited is a consortium consisting of Medco Power Indonesia, INPEX, Ormat Technologies, Itochu Corporation, and Kyushu Electric Power.

Sarulla Operations Limited was established in 2006 when PLN, the national power company of Indonesia, awarded the company to take over the development of the Sarulla geothermal project in North Sumatra.

The Sarulla geothermal resources, situated in North Sumatra, were first discovered by Unocal Geothermal. From 1993 to 1998, Unocal carried out extensive exploration in the Sarulla geothermal working area, drilling a total of 13 deep wells. This exploration confirmed the presence of 330 MW of commercial geothermal reserves, estimated to be viable for 30 years.

However, due to the Asian financial crisis in 1997, Unocal did not get the approval to build the power plants.

With a total investment of 1.7 billion USD, Sarulla Operation Limited completed the first power station in March 2017, the second station in October 2017, and the third station in March 2018.

Here are the three power stations that SOL operates:
• 110 MW Silangkitang (SIL) Unit 1
• 110 MW Namora-I-Langit (NIL) Unit 1
• 110 MW Namora-I-Langit (NIL) Unit 2

PLN GAS AND GEOTHERMAL

PLN Gas and Geothermal is a subsidiary company of Perusahaan Listrik Negara (PLN), the national power company of Indonesia.

As the sole distributor of electricity in Indonesia, besides purchasing electricity from all independent geothermal operators, PLN also operates several geothermal power plants of its own.

Here are the geothermal plants which PLN operates:
• 110 MW Ulubelu Unit 1 and Unit 2 – Steam supplied by Pertamina Geothermal Energy
• Kamojang Unit 1 (30 MW), Unit 2 (55 MW), and Unit 3 (55 MW) – Steam supplied by Pertamina Geothermal Energy
• 10 MW Ulumbu Unit 1,2,3,4 in Flores
• 2.5 MW Mataloko in Flores

PLN has an ambitious plan to produce more geothermal power from its geothermal work areas. It is working further to develop the geothermal resources in Ulumbu and Mataloko. It has a plan to build 20 MW Ulumbu Unit 5 and two 10 MW power stations in Mataloko.

It is also currently looking for international and national investors to partner and collaborate to develop the following four geothermal projects:
• 20 MW Tulehu in Central Maluku
• 10 MW Atadel in East Nusa Tenggara
• 10 MW Songa Wayaua in North Maluku
• 20 MW Tangkuban Perahu in West Java

MEDCO CAHAYA GEOTHERMAL

Indonesia welcomes its newest geothermal power plant, the 35-MW Ijen geothermal power plant, which started commercial operations in February 2025 in East Java.

The Ijen power plant is developed and operated by Medco Cahaya Geothermal (MCG), which is a joint venture between Medco Power Indonesia and Ormat Technologies.

Medco Power is not new to geothermal energy. It has a stake in the big 330-MW Sarulla geothermal power plant operated by Sarulla Operations in North Sumatra.

With the entrance of MCG, Indonesia now has eight geothermal power plant operators.

Epilogue
As Indonesia is eager to increase its electricity generation using renewable resources, and with its abundant geothermal resources in its backyard, we shall see more geothermal development in the future.

Jamin Djuang – Chief Learning Officer of LDI Training