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Indonesia’s geothermal push runs into local fears at Mount Ungaran
Indonesia’s geothermal push runs into local fears at Mount Ungaran. Originally published by Mongabay.
By Triyo Handoko · 2026-09-24T13:06:30.201Z
YOGYAKARTA, Indonesia — Communities living near Mount Ungaran in Indonesia’s Central Java province have slammed plans to revive a geothermal power project there, saying it could threaten water supplies and farming livelihoods. The latest opposition follows a decision in August by the Ministry of Energy and Mineral Resources allowing the state owned electricity utility, PLN, to conduct geothermal exploration and development at Mount Ungaran. Local opposition to the plans began in 2008, shortly after the ministry first designated Ungaran, an active volcano, as a geothermal working area. The latest decision has revived the long running dispute between the government and local communities. Rahman, coordinator of the Semarang Menggugat Alliance ASM , said communities around Mount Ungaran depended on farming and local water sources, and feared the project could affect both. “We can already make a living from farming,” Rahman, a resident of Bawen subdistrict, said in early September. “If geothermal development goes ahead, we are concerned that our water sources could decline or become polluted, affecting agriculture.” Indonesia sits in one of the most seismically active zones in the world, which gives it massive potential to generate electricity from geothermal energy: an estimated 23.2 gigawatts, according to the latest data from the Ministry of Energy and Mineral Resources. The ministry describes https://esdm.go.id/en/media center/news archives/kejar potensi panas bumi nomor satu dunia bahlil minta pengembang tak tahan konsesi Indonesia as having the world’s largest geothermal resource potential, ahead of countries including the United States and the Philippines. But the country’s total installed geothermal capacity is a fraction of its potential, at about 2.78 GW as of August 2026 https://www.esdm.go.id/en/media center/news archives/kejar potensi panas bumi nomor satu dunia bahlil minta pengembang tak tahan konsesi . That means barely an eighth of the country’s estimated geothermal potential has been tapped for electricity generation. The ministry estimates Ungaran has geothermal potential of 55 megawatts, and is targeting commercial electricity generation there to begin in 2031. The project is currently in the exploration phase, which is expected to continue until 2029. This phase of the project will include technical studies, permitting, and drilling to determine whether the area contains sufficient geothermal resources for power generation. Energy ministry spokesperson Dwi Anggia said geological and geophysical studies would be used to assess conditions beneath the surface and identify areas that could contain geothermal reservoirs — underground pockets of hot water and steam trapped in rocks, which can be extracted to generate electricity at the surface. Anggia said the project could move to the next stage if the exploration results meet technical, economic, environmental, licensing, and safety requirements. Dwi Suryono, head of renewable energy at the Central Java provincial energy department, said the exploratory drilling could go as deep as 2,200 meters about 7,200 feet . “If the work stays on schedule, drilling is expected to take place in late 2028 or early 2029,” Suryono said. “If sufficient geothermal resources are confirmed, construction of the necessary infrastructure would follow, with commercial electricity generation targeted for 2031.” Before this, however, the project developers will also need to secure a rash of permits and approvals, including for zoning, the use of forest areas, and an environmental impact assessment, Suryono said. Central Java Deputy Governor Taj Yasin said the provincial government would facilitate dialogue with residents opposed to the project. “This is a licensing decision made by the central government, so we are still studying it,” he said https://jatengprov.go.id/publik/soal proyek panas bumi gunung ungaran pemprov jateng siap jembatani aspirasi warga/ . “The provincial government is ready to facilitate the community’s aspirations.” Yasin said residents’ concerns about the potential impact of geothermal development should be considered by all parties. Energy and mining activities that interact directly with the environment and residential areas, he said, should prioritize safety, environmental sustainability, and the welfare of nearby communities. Rahman said residents were concerned not only about the potential impact on springs that support farming and local livelihoods, but also about possible disaster and toxic exposure risks associated with the project. He said geothermal drilling could trigger active faults and potentially increase earthquake risks, adding that gases released during geothermal operations could reach the surface, leaving nearby communities exposed. “Of course, this would greatly disrupt our lives,” Rahman said. “It would make residents more vulnerable, even though we have lived safely and comfortably here for years. There are already many examples.” The history of geothermal development across Indonesia is marked by a string of disputes between developers and local communities over environmental impacts, land use, and livelihood concerns. At the Sorik Marapi geothermal project in North Sumatra, residents in September 2022 reported a strong smelling gas from a well site, with some complaining of breathing difficulties and vomiting. The energy ministry attributed the emission https://www.esdm.go.id/id/media center/arsip berita/kronologis kejadian paparan gas h2s area wellpad t 11 pltp sorik marapi to testing being carried out at the well. In Central Java, the Dieng geothermal project has faced longer running opposition from some local communities over concerns including water resources, environmental impacts, land use, and safety. Recent academic studies have documented https://www.sciencedirect.com/science/article/abs/pii/S2214629626002318 tensions between the project and residents, including opposition to the planned expansion of the Dieng geothermal power plant. In Ungaran, Rahman noted the potential impact on cultural heritage sites around the volcano. Part of the area has been designated by the government as a national cultural heritage zone, covering the Gedong Songo complex, a collection of Hindu temples dating back some 1,300 years. Rahman said residents regarded the temple complex as an important part of the local community’s cultural and spiritual identity that must be preserved. “It also has spiritual value for us, which is why we have opposed the project from the beginning,” he said. Many experts have echoed the residents’ concerns while also questioning the feasibility of commercial scale electricity generation at Mount Ungaran. Some studies have shown much lower estimates than the ministry’s claimed 55 MW. A 2025 study https://digilib.itb.ac.id/gdl/view data/pemodelan termodinamika dan keekonomian pembangkit listrik berdasarkan data 3g geologi geokimia geofisika wilayah kerja panas bumi gunung ungaran by Wahyu Setia Aji from the Bandung Institute of Technology ITB , Indonesia’s top engineering university, estimated that the Gedong Songo area, a priority zone within the Mount Ungaran geothermal working area, could support about 20 22.6 MW of electricity generation, depending on the technology used. The provincial energy department reported a similar figure in its 2021 performance report https://data.jatengprov.go.id/dataset/20811210 4530 42d5 86a8 672be8273ef7/resource/edf52b18 a5a9 4016 ae41 74053fc1ba71/download/triwulan i 2022.pdf . It said the initial estimate of 55 MW should be reduced to about 20 MW following surveys and recalculations, adding this lower estimate means the project no longer meets the threshold for economic feasibility. The department didn’t provide further details in the report explaining the drastic reduction in its estimates. However, the central government, which is pushing the project, has given a substantially higher figure. In its 2008 2027 National Electricity General Plan https://jdih.esdm.go.id/dokumen/download?id=Kepmen+ESDM+2682+2008.pdf , the energy ministry puts the geothermal prospect at Ungaran at 100 MW. Fajar Muhammad Andhika, head of the agrarian and coastal environment division at the Semarang Legal Aid Institute LBH Semarang , said the discrepancies raise questions about the basis for advancing the project. He also criticized what he described as limited public participation as the government seeks to move the project forward. Residents have received little detailed information about the plan, Fajar said, despite being among those who could be affected if development proceeds. “This situation shows that the government’s energy policies are not based on the principle of justice,” he said. “The lack of adequate information will make residents increasingly vulnerable.” Fajar called on the government to provide comprehensive information and involve residents in discussions before issuing permits, rather than opening dialogue only after opposition has intensified. “This project needs to be evaluated comprehensively,” he said. Wishnu Try Utomo, advocacy director at the Jakarta based Center of Economic and Law Studies Celios , also questioned the exploration history of the Ungaran project and the government’s decision to revive it. His own research showed the original exploration permit was held by PT Giri Indah Sejahtera, which conducted exploration between 2010 and 2013. The permit was subsequently transferred to PLN, the state owned utility, in 2017 under an energy ministry decree. PLN then conducted exploration from 2017 to 2022, according to Wishnu. He said the findings from both periods of exploration have never been publicly disclosed. The ministry has said exploration is still ongoing to establish the geothermal resource and assess whether development is feasible. “After PLN received an exploration permit in 2017, why has it been given another one this year?” Wishnu said. “Does this mean the earlier exploration was insufficient? The project should not be pushed ahead if its economic viability or energy potential has not been adequately established.” He also questioned the decision to zone the area as a “geothermal working area” in 2007. That same year, the energy ministry also designated several other geothermal areas across the country, including Cisolok Cisukarame in West Java province, Telaga Ngebel in East Java, and Jailolo in North Maluku. Wishnu cited the Cisolok Cisukarame project as an example of the risks associated with geothermal exploration. He said exploratory drilling there failed to produce the expected results, and argued the government should avoid repeating such an outcome as it seeks to accelerate geothermal development. “We should not allow the same thing to happen again, particularly now that geothermal exploration is receiving state funding,” he said. The Ungaran exploration is being financed by the central government under the Geothermal Sector Infrastructure Financing Fund, or Dana PISP, which is administered by state owned infrastructure financing company PT Sarana Multi Infrastruktur SMI . Established in 2022, the fund is intended to support geothermal infrastructure development and exploration and to help attract investment to a sector where exploration carries significant financial risks. Wishnu said the financing mechanism — effectively a subsidy — could make geothermal projects more attractive to companies by reducing some of the financial risks associated with exploration. He argued that this could encourage developers to pursue projects even where questions remain over their economic and resource potential. He described the government’s use of the financing scheme as “greenwashing,” saying the benefits could accrue to companies while communities near project sites bear the environmental and social risks. The fund’s charter, however, states that its support for geothermal infrastructure development includes environmental management and climate change mitigation and adaptation. Wishnu also said the costs of geothermal power could eventually affect electricity consumers, with high generating costs being passed on in the form of higher rates for household electricity. He added residents’ concerns about water availability and possible exposure to geothermal gases, along with the Ungaran area’s relatively dense population and reliance on farming and tourism, should all be grounds for reconsidering the project. “The threats are real, especially when we look at similar projects in Dieng,” he said. “Ungaran is also relatively densely populated, with agriculture and tourism both relying on water resources.” The central government, meanwhile, is seeking to expand geothermal power as part of Indonesia’s broader energy transition and energy security strategy. Under its 2025 2034 Electricity Supply Business Plan RUPTL https://esdm.go.id/id/media center/arsip berita/dongkrak energi bersih menteri esdm tekankan pentingnya komitmen laksanakan ruptl , PLN aims to build an additional 5.2 GW of geothermal generating capacity. Separately, the energy ministry said https://ebtke.esdm.go.id/artikel/berita/dorong swasembada energi pemerintah genjot pengembangan panas bumi melalui skema pspe in May 2025 that the government plans to add 3.36 GW of geothermal capacity by 2030, rising to 5 GW by 2034. The government has also sought to accelerate geothermal development through regulatory reforms, incentives, and greater investment, while urging holders of geothermal concessions to fast track development https://esdm.go.id/en/media center/news archives/kejar potensi panas bumi nomor satu dunia bahlil minta pengembang tak tahan konsesi rather than allow projects to remain stalled at the permitting stage. ASM’s Rahman said he and other residents previously raised their objections with two Central Java governors, first with Bibit Waluyo around 2010 and later with Ganjar Pranowo in 2019. “We will raise our concerns again with the current governor,” he said. This story was first published here https://mongabay.co.id/2026/09/17/khawatir daya rusak warga tolak proyek panas bumi ungaran/ in Indonesian on Sept. 17, 2026. Basten Gokkon is a senior staff writer for Indonesia at Mongabay. Permana, Y. S., Suryani, D., Hanif, H., & Alfirdaus, L. K. 2026 . Fragmented resistance in energy transitions: Geothermal materiality in Dieng, Indonesia. Energy Research & Social Science , 136, 104760. doi: 10.1016/j.erss.2026.104760 https://doi.org/10.1016/j.erss.2026.104760 Aji, W. S. 2025 . Pemodelan termodinamika dan keekonomian pembangkit listrik berdasarkan data 3G geologi, geokimia, geofisika Wilayah Kerja Panas Bumi Gunung Ungaran Master’s thesis, Bandung Institute of Technology, Bandung, Indonesia . Retrieved from https://digilib.itb.ac.id/gdl/view data/pemodelan termodinamika dan keekonomian pembangkit listrik berdasarkan data 3g geologi geokimia geofisika wilayah kerja panas bumi gunung ungaran https://digilib.itb.ac.id/gdl/view data/pemodelan termodinamika dan keekonomian pembangkit listrik berdasarkan data 3g geologi geokimia geofisika wilayah kerja panas bumi gunung ungaran Flores’ geothermal ambitions collide with justice, culture & local resistance https://news.mongabay.com/2026/01/flores geothermal ambitions collide with justice culture local resistance/ FEEDBACK: Use this form https://form.jotform.com/72625128446155 to send a message to the author of this post. If you want to post a public comment, you can do that at the bottom of the page.