Indonesia is the second-largest geothermal energy producer in the world after the USA.
Located right on the long stretch of the ring of fire, Indonesian islands are endowed with rich geothermal resources. The total potential geothermal resources of Indonesia are estimated at 28,000 MW.
Although the geothermal potential is huge, its utilization rate is under 8%. Currently, the total installed power generating capacity from the active 16 geothermal power plants in Indonesia is 2133 MW.
Here are the top ten largest geothermal plants in Indonesia in 2020.
The Kamojang Geothermal Plant
Operating since 1982, the 235 MW Kamojang plant is the first geothermal power plant in Indonesia. Located in the Garut area in West Java, it has been operating for 38 years.
The Dutch spotted the Kamojang geothermal potential more than one hundred years ago and drilled several wells in the area. In 1926 it successfully drilled the first steam producing well in Kamojang, also the first in Indonesia.
Later in I971, Pertamina Geothermal Energi (PGE) with cooperation from New Zealand began to develop the field followed by the construction of the Kamojang power plant, the first geothermal power plant in Indonesia.
The plant is operated by Pertamina Geothermal Energi.
The Salak Geothermal Power Plant
Producing 377 MW of power, the Salak plant is the largest geothermal power plant in Indonesia and is also one of the largest in the world.
Located at Gunung Salak in West Java, the Salak plant has been operating since 1994.
The Salak geothermal resources were initially explored and developed by Unocal. In 2005, the Salak geothermal assets were taken over by Chevron who eventually sold it to Star Energy in 2017.
The Darajat Geothermal Plant
The 270 MW Darajat geothermal plant, located at Garut in West Java, started its commercial operation in 1994 and is one of the oldest geothermal power plants in Indonesia.
The Darajat geothermal assets were initially explored and developed by Amoseas. The assets were later taken over by Chevron who eventually sold it to a consortium led by Star Energi in 2017.
The Darajat resource has two special characteristics. First, it is one of only a few dry steam fields in the world.
Secondly, the Darajat wells are highly productive. While the worldwide average capacity of a geothermal well is 5 to 10 MW, a Darajat well can produce 40 MW of power.
The Sarulla Geothermal Plant
The Sarulla geothermal power plant, with 330 MW capacity, is the second-largest geothermal plant in Indonesia and is also one of the largest geothermal plants in the world.
The Sarulla geothermal resources, located in North Sumatera, were initially discovered by Unocal. Unocal conducted extensive exploration in the Sarulla geothermal working area from 1993 to 1998. It drilled a total of 13 deep wells and proved the existence of 330 MW of commercial geothermal reserves for 30 years.
However, due to the Asian financial crisis in 1997, the Unocal proposed power plant was not constructed until after the project was taken over by Sarulla Operation Limited (SOL).
Sarulla Operation Limited completed the power plant in 2016. The company is a consortium consisting of Medco Power Indonesia, INPEX, Ormat International, Itochu Corporation, and Kyushu Electric Power.
The Muara Laboh Geothermal Plant
Completed in 2019, the 85 MW Muara Laboh geothermal plant is the newest plant among the ten largest geothermal power plants in Indonesia.
The Muara Laboh geothermal plant is located in West Sumatera and is operated by Supreme Energy Muara Laboh (SEML).
It took the company 12 years to complete the geothermal project at 587 million US dollars.
The operator of the project, PT Supreme Energy Muara Laboh (SEML), is a consortium consisting of PT Supreme Energy, ENGIE, and Sumitomo Corporation.
Having proven reserves of 200MW, the company is in negotiation with PLN, the national power company, to build a second power generation unit.
The Ulubelu Geothermal Plant
Operating since 2012 and located at Lampung in Sumatera, the 220 MW Ulubelu geothermal power plant is operated by Pertamina Geothermal Energi.
The combined 220 MW power comes from the four 55 MW power generation units.
The Lahendong Geothermal Plant
The 120 MW Lahendong geothermal plant is located in Tomohon in North Sulawesi. The Lahendong plant started to operate commercially in 2001 and Pertamina Geothermal Energi (PGE) is the operator.
Its combined 120 MW power is generated from the five 20 MW power generation units.
The Wayang Windu Geothermal Plant
Located in the Bandung area in West Java, the 227 MW Wayang Windu geothermal plant began its commercial operation in 1999.
Star Energy operates the Wayang Windu geothermal assets under a joint cooperation contract with Pertamina Geothermal Energi.
The Dieng Geothermal Plant
The 60 MW Dieng geothermal power plant started to operate in 1998. The Dieng plant is located in the Dieng area in Central Java and is operated by Geo Dipa Energi.
Geo Dipa Energi is currently working on the following projects in the Dieng work area:
- Adding a small 10 MW power plant.
- Developing a 55 MW Dieng-2 power plant (PLTP Dieng Unit 2)
- Developing a 55 MW Dieng-3 power plant (PLTP Dieng Unit 3)
The Patuha Geothermal Plant
The 55 MW Patuha geothermal plant located at the Ciwidey area in West Java has been in operation since 2014.
Geo Dipa Energi as the operator is committed to drill 12 new wells beginning in 2021 and construct a second 55 MW power plant. Its long-term plan is to increase the Patuha power generation capacity to 400 MW.
Other Geothermal Plants in Indonesia
Sixteen geothermal power plants are operating in Indonesia currently. Besides the above top ten largest plants, here are two other geothermal plants that are worth mentioning.
The Lumut Balai Geothermal Plant
The 55 MW Lumut Balai geothermal plant, located at Muara Enim in South Sumatera, started to operate commercially in 2019.
Pertamina Geothermal Energi operates the Lumut Balai assets and the company is planning to build a second power generation unit.
The Sorik Marapi Geothermal Plant
The Sorik Marapi geothermal power plant located in Mandailing Natal in North Sumatera has a total installed capacity of 90 MW.
Its first 45 MW unit came online in 2019 and the second 45 MW unit was inaugurated on 28 July 2021.
The Sorik Marapi geothermal plant was developed by ORKA Energy and operated by PT Sorik Marapi Geothermal Power.
The Rantau Dedap Geothermal Plant
The Rantau Dedap geothermal power plant, located in South Sumatera, is the latest geothermal power plant that came online in Indonesia. Currently, it consists of two power stations, Unit 1 and Unit 2 having a total installed capacity of 98.5 MW.
The power plant is operated by PT Supreme Energy Rantau Dedap (SERD), a consortium consisting of Supreme Energy, Marubeni, ENGIE, and Tohoku Electric Company.
Here are the timelines of the geothermal project:
2010 – The concession for the Rantau Dedap was awarded to Supreme Energy.
2011 – Geoscientific exploration began.
2014 – Exploration drilling began.
2015 – A total of 6 exploration wells were completed by 2015.
2016 – The company confirmed the 92 MW of proven reserve capacity.
2018 – Power plant construction began.
2021 – Completed the Unit 1 power station.
The 49.25 MW Unit 1 station was successfully synchronized to PLN’s power grid on 5 October 2021. PLN – Perusahaan Listrik Negara – is the national electricity company of Indonesia.
The Unit 2 station is expected to be completed by the end of 2021.
PT Supreme Energy Rantau Dedap plans to further develop the geothermal potential in the Rantau Dedap geothermal work area with a total development target of 240 MW.
Geothermal is Rising in Indonesia
The list of the top largest power plants in Indonesia will likely change in 2021 as several new power plants will be completed in near future.
The Indonesian government is very keen to develop its vast geothermal resources to increase the contribution of renewable energy in its energy mix. Its targets are to increase the geothermal power generation capacity to 7500 MW by 2025 and 9300 MW by 2035.
To meet these targets, the government will provide funds to help companies in their exploration drillings, provide tax holidays, and remove certain taxes.
With a total of 265 potential sites for geothermal plants located across the country, the utilization of the geothermal resources should continue to increase long into the future in Indonesia.
Written by Jamin Djuang – Chief Learning Officer of LDI Training and author of The Story of Oil and Gas: How Oil and Gas Are Explored, Drilled, and Produced