Echoes of Resistance: The Controversy Surrounding the Gunung Ungaran Geothermal Project

Semarang, Central Java — The pursuit of renewable energy in Indonesia continues to face grassroots friction. Plans to develop the Gunung Ungaran Geothermal Power Plant (PLTP) in Central Java have reignited fierce opposition from local communities, environmental advocates, and legal experts. Despite government assurances and ambitious net-zero timelines, the project is marred by a history of uncommunicated explorations, sharply conflicting potential estimates, and deep-seated fears regarding ecological degradation and the loss of cultural heritage.

Through a formal decree issued by the Ministry of Energy and Mineral Resources (ESDM)—specifically Decree No. 134.TK/EK.04/MEMBPE/2026—the state-owned electricity company PT PLN (Persero) has been officially tasked with continuing the exploration and development of geothermal resources in the Mount Ungaran region.

While the central government views this as a vital step toward expanding the nation’s green energy portfolio, the local population views it as an existential threat to their water sources, agricultural livelihoods, and ancestral identity.

Main Facts: The Scope of the Project and the Core Conflict

Under the current government timeline, the exploratory phase of the Gunung Ungaran PLTP is targeted for completion by 2029, with commercial operations slated to begin by 2031. The project blueprint outlines deep-drilling operations reaching depths between 1,900 and 2,200 meters into the earth’s crust. The objective is to tap into subterranean reservoirs containing pressurized hot water and steam, which will then be harnessed to drive electricity-generating turbines.

However, the geographic and social reality of Mount Ungaran complicates these technical ambitions. The mountain is not merely an energy asset; it is a vital ecological buffer and an agrarian heartland.

Local residents, alongside civil society organizations such as the Semarang Awakening Alliance (Aliansi Semarang Menggugat), argue that the risks heavily outweigh the promised benefits. The primary points of contention include:

• Water Security: Fears that deep drilling will disrupt underground aquifers, leading to reduced water discharge or contamination that could cripple local farming.
• Geological Hazards: Concerns over potential gas leaks and the destabilization of active local fault lines (sesar aktif).
• Cultural Preservation: The project’s proximity to the Gedongsongo Temple Complex, a nationally protected cultural heritage site (cagar budaya nasional) of immense spiritual and historical value.

Chronology of Contention: A Long History of Distrust

The friction surrounding the Gunung Ungaran geothermal project is far from new; it is the latest chapter in a nearly two-decade-long saga of friction between the state and the local populace.

• 2007: The Mount Ungaran region is officially designated as a Geothermal Working Area (WKP). This initial legal classification sparked the first wave of community anxiety and localized pushback.
• 2010–2013: Private energy companies were granted concessions to conduct early-stage exploration. Despite drilling or surveying activities taking place, the results, environmental impact assessments, and transparency reports were never publicly disclosed to the surrounding communities.
• 2017–2022: PT PLN took over exploration duties in a subsequent push. Much like the earlier private venture, the findings of this operational window remained shrouded in bureaucratic secrecy, breeding deep distrust among residents who felt kept entirely in the dark.
• 2026: The Ministry of ESDM issues Decree No. 134.TK/EK.04/MEMBPE/2026, officially greenlighting PLN to resume operations, effectively reviving dormant fears and immediately mobilizing community-led resistance.

Supporting Data: Discrepancies and Economic Viability Under Fire

One of the most damning criticisms leveled against the Gunung Ungaran project is the glaring inconsistency in official data regarding the actual energy potential of the site. Critics argue that pushing forward with a project built on shaky, contradictory estimates is economically irrational and environmentally reckless.

A comparative look at the data highlights the wild fluctuations in projected capacity:

1. National General Electricity Plan (RUKN) 2008–2027: Historically listed the Gunung Ungaran geothermal prospect as having a massive potential yield of up to 100 megawatts (MW).
2. Ministry of ESDM Baseline: More recent ministerial assessments peg the potential at 55 MW, forming the nominal justification for the current round of exploration.
3. Central Java ESDM Department Report (2021): Following initial surface surveys and recalculated geological modeling, the provincial agency revised the 55 MW estimate downward, indicating that the viable capacity was significantly lower.
4. Bandung Institute of Technology (ITB) Study (2025): Independent research conducted by ITB researchers projected the realistic power generation capacity of the Ungaran reservoir to be a modest 20 MW.

The 2021 Central Java ESDM report explicitly noted the economic implications of these shifting figures: "With the decline in potential capacity, it impacts the failure to meet economic value thresholds." In simpler terms, the energy yielded may not justify the capital expenditure or the ecological toll.

Wishnu Try Utomo, a researcher at the Center of Economic and Law Studies (Celios), has publicly questioned the rationale behind handing the project back to PLN.

"We must ensure this project is not forced through if it clearly lacks sufficient economic and energy potential," Utomo stated, highlighting the risk of squandering public funds on a sub-viable energy venture.

Official Responses: Balancing Transition with Local Welfare

As opposition mounts, regional authorities have attempted to position themselves as mediators between national green energy targets and community preservation.

Taj Yasin, the Deputy Governor of Central Java, addressed the brewing conflict by asserting the provincial government’s commitment to hearing local grievances. He emphasized that any energy development project intersecting with populated areas and fragile ecosystems must strictly prioritize public safety, environmental sustainability, and community welfare.

However, statements from regional officials have done little to placate residents who demand concrete policy guarantees rather than generalized diplomatic assurances.

Implications: Information Asymmetry and Community Vulnerability

For civil society and legal watchdogs, the Gunung Ungaran case exemplifies a broader structural flaw in Indonesia’s green energy transition: the sidelining of local communities in favor of top-down bureaucratic mandates.

Fajar Muhammad Andhika, a representative from the Legal Aid Foundation (LBH Semarang), argued that the project has been fundamentally flawed from its inception due to a persistent lack of transparency. According to Andhika, the communities bearing the brunt of the ecological and social risks are consistently the last to receive accurate, comprehensive information.

"The absence of adequate information makes residents increasingly vulnerable," Andhika noted. He criticized the government’s reactive approach, pointing out that authorities tend to engage with communities only after resistance flares up, rather than practicing transparent, prior consultation before issuing binding decrees.

The Agrarian and Spiritual Cost

For local farmers, the stakes are measured in daily survival rather than megawatt hours. Rahman, Coordinator of the Semarang Awakening Alliance, painted a vivid picture of rural stability under threat:

"We are already prosperous through farming. If geothermal comes in, our water sources will diminish and become polluted. Consequently, our agriculture will be severely disrupted," Rahman explained.

Beyond sustenance, the cultural dimension cannot be overstated. The foot of Mount Ungaran is home to the historic Gedongsongo Temple complex. Built during the Sailendra dynasty in the 8th century, these Hindu temples are deeply intertwined with the spiritual and cultural identity of the surrounding population.

"This temple complex is our identity; it is a part of our culture that must be preserved," Rahman added, voicing fears that industrial heavy machinery and seismic disruption from drilling could permanently mar a sacred landscape.

Conclusion

The renewal of exploration at Gunung Ungaran highlights a critical dilemma in Indonesia’s green transition: how to balance national decarbonization goals with local environmental justice. While geothermal energy is an indispensable pillar of Indonesia’s renewable future, the path to harnessing it cannot bypass the consent, safety, and well-being of the people living in its shadow.

Without transparent data, genuine prior public consultation, and ironclad environmental safeguards, projects like the Gunung Ungaran PLTP risk trading one ecological crisis for a social one—turning clean energy aspirations into a source of enduring local conflict.