Tug-of-War Between Cultural Heritage and Geothermal Projects in Mount Ungaran
A geothermal energy utilisation project in Mount Ungaran, Central Java, has triggered a petition of opposition signed by thousands of residents. The controversy involves a tension between the preservation of cultural heritage and community living spaces versus the fulfilment of national energy requirements.
The Deputy Director of the Environmental Law Centre (Walhi) for Central Java, Nur Cholis, revealed that the geothermal exploration project in Mount Ungelse Ungaran has the potential to cause destructive impacts, not only ecologically but also to the preservation of cultural heritage sites. This is due to the exploration area being located near the Gedong Songo Temple structure.
“From an ecological perspective, geothermal extraction poses a high risk to environmental carrying capacity, particularly regarding water consumption and the preservation of springs. We can look at the Dieng Plateau as a lesson; in Pawuhan Hamlet, residents struggle to access clean water because their water sources are strongly suspected to have been affected and turned saline due to activities around the Dieng geothermal power plant,” Nur stated during an interview on Tuesday (1/9/2026).
He also highlighted that the geothermal exploration area in Mount Ungaran is adjacent to the Gedong Songo Temple. According to him, the project risks threatening the temple’s structural integrity. “The potential impact is highly threatening and destructive. Gedong Songo Temple is not only a cultural heritage and historical site that must be protected, but it also serves as a pillar for the living space and the economic lifeline (tourism) of the local community,” he said.
Nur warned that geothermal project activities involve large-scale land clearing, the mobilisation of heavy machinery, drilling, and the potential release of toxic gases (such as H2S) and seismic vibrations. “Vibrations from drilling activities pose a significant risk to the structure of the centuries-old temple. Furthermore, if groundwater patterns are disrupted by drilling, the area could potentially experience land subsidence,” he added.
“If this project proceeds, the government will not only sacrifice the ecosystem but also destroy historical and cultural heritage, as well as the livelihoods of local residents,” Nur added.
He argued that the geothermal project in Mount Ungaran lacks urgency, as the electricity supply, particularly for Central Java and the Special Region of Yogyakarta (DIY), exceeds current demand. “Based on 2025 data from PLN UID Jateng-DIY, the electricity system in Central Java-DIY is currently in surplus: installed capacity reaches approximately 6,400 MW, while peak load is around 4,200 MW. There is a remaining capacity of about 2,200 MW (44.94 per cent). Given this oversupply, we believe Central Java does not yet have an urgent need to add new large-scale power plants, especially in landscapes that are vital to the community,” he said.
Nur noted that based on numerous studies, the potential negative impacts of the Mount Ungaran geothermal project are far greater for the environment and local social structures, such as the threat of pollution and the loss of livelihoods. Additionally, he mentioned that from an economic-political perspective, geothermal projects often utilise debt schemes that burden the state.
“Regarding governance, the transparency of geothermal projects must be strictly monitored. Referring to public information and reports regarding the Dieng 1 geothermal plant, there are allegations of potential losses related to the tender process and procurement worth Rp25.69 billion. This is a critical note for us that the governance of such projects remains highly vulnerable to transparency issues,” said Nur.
Meanwhile, the Head of the Energy and Mineral Resources Office (ESDM) for Central Java, Agus Sugiharto, stated that he does not take issue with the emergence of the petition opposing the geothermal project in Mount Ungaran. However, he warned against making defamatory claims regarding environmental destruction, as the project has not yet commenced.
“It is perfectly legitimate to express opinions. As long as it is within the constitution, people are allowed to voice their views. Disagreement is a form of democracy,” Agus said when interviewed at the Central Java Regional House of Representatives (DPRD) office on Monday (31/8/2026).
Nevertheless, he reminded that the project is based on legal foundations and needs to be studied. “Do not just accuse or slander things that have not been done. It hasn’t even started, yet there are slanders about destruction; there is no evidence,” he said.
Agus then referenced the Dieng and Kamojang geothermal power plants. According to him, both plants have proven not to damage the surrounding areas, let alone cultural heritage sites. “Now, show me where existing geothermal activities are causing damage? Not just in Indonesia, but worldwide, many geothermal developments are happening,” he said.
He explained that the issuance of geothermal utilisation permits in Mount Ungaran falls under the authority of the central government. However, the Central Java ESDM Office, as a regional agency, has also received information regarding the project plans.
“In the second semester of 2026, studies will be conducted, including social studies, followed by socialisation down to the village level, managing permits, and creating detailed engineering designs for the access roads that will be used,” Agus explained.
He added that all these steps will be taken once the details of the exploration activities are finalised. “Therefore, I believe there is no need for panic. We can see that geothermal energy development, not only in Indonesia, is a form of green energy that is environmentally friendly,” he said.
According to Agus, geothermal projects are unlikely to damage the environment. “In reality, geothermal energy utilisation does not damage the environment because the reservoir or water vapour taken must be preserved by maintaining the environment…