Hans Nicholas Jong, Jakarta – Indonesia is seeking to redraw the boundaries of a UNESCO World Heritage rainforest to pave the way for geothermal projects – part of its renewable energy push but a move environmentalists warn could devastate biodiversity and tarnish the country's green reputation.
The Ministry of Forestry has proposed excluding two degraded areas – Suoh and Sekincau in Bukit Barisan Selatan National Park, Lampung province – from the Tropical Rainforest Heritage of Sumatra (TRHS).
The TRHS is a 2.5 million-hectare (6.2 million-acre) site that also spans Gunung Leuser and Kerinci Seblat national parks, making it one of the largest conservation areas in Southeast Asia and the last habitat for many endangered animals.
Officials say the boundary change would free up some of the site's vast geothermal potential, estimated at 5 gigawatts (GW), while maintaining TRHS's Outstanding Universal Value (OUV) required by UNESCO.
"TRHS sites cannot [be used for geothermal], but we know there is huge potential there. It would be a pity not to make use of it," said Satyawan Pudyatmoko, the ministry's director-general of ecosystem conservation, as quoted by local media Sept. 18.
The government submitted the proposal in November 2023, with a decision expected in 2027.
A clash of definitions
As a country that heavily relies on coal for its power generation, Indonesia has pledged to transition away from fossil fuels and scale up renewable energy as part of its climate commitments under the Paris Agreement. Geothermal, which draws from the country's volcanic geography, is one of the technologies the government is aggressively promoting.
But under UNESCO rules, geothermal is categorized as mining, which is prohibited in World Heritage sites. By contrast, Indonesian law defines it as the use of "environmental services," creating a regulatory gap that has blocked projects in TRHS.
To overcome that, the government is asking UNESCO to approve a boundary modification, excluding 52,715 hectares (130,000 acres) in Suoh and Sekincau from TRHS. That's equal to one-third the size of London and about 15% of Bukit Barisan Selatan National Park.
If approved, geothermal development could begin as early as 2027, Satyawan said.
Indonesia first floated the idea of exploiting TRHS's geothermal resources in 2013, prompting UNESCO and IUCN to warn of possible impacts on biodiversity and recommend a full environmental impact assessment (EIA).
A rainforest on the danger list
The TRHS was declared a World Heritage Site in 2004 for its immense biodiversity: more than 10,000 plant species, 200 mammals and 580 birds, including critically endangered Sumatran orangutans (Pongo abelii), tigers, rhinos and elephants.
Several mammals, such as the Sumatran orangutan, are found nowhere else on Earth, making TRHS a crucial site for understanding the island's biogeographic evolution.
But deforestation, illegal logging, encroachment and road building have led UNESCO to list TRHS as a World Heritage in Danger since 2011.
Environmentalists warn that removing land for geothermal development risks worsening pressures on a forest ecosystem already in decline, making it harder to get TRHS off the danger list.
Geothermal plants require extensive infrastructure, including access roads, which often open the way for further deforestation and encroachment.
A 2019 study found geothermal projects in Indonesia required nearly twice as much road construction as similar projects elsewhere: about 10 kilometers (6.2 miles) of roads per 100 megawatts of capacity, compared with about 5 km (3.1 mi) globally. Critics warn that could further fragment habitats and erode OUV.
The government's own 2025 report acknowledges energy projects in Bukit Barisan Selatan National Park, including the Suoh-Sekincau geothermal power plant, will cut across the ranges of tigers, elephants, rhinos and even the giant flower Rafflesia – habitats recognized by UNESCO as meeting Criterion X for global biodiversity conservation.
The narrative that geothermal is clean and low-impact often overlooks these risks, said Ki Bagus Hadikusuma, energy researcher at the NGO Auriga Nusantara.
He cited Sorik Marapi in North Sumatra, where gas leaks since 2022 have sent dozens of people to hospital and killed five, including two children.
Geothermal is also a water-hungry industry, like mining, which could threaten critical water sources in protected forests, Ki Bagus added.
Global examples have also raised alarms: In South Korea, a geothermal project in Pohang was linked to a damaging earthquake – a worrying precedent for Indonesia, which sits on the seismically active Ring of Fire.
Government defense: Degraded lands and offsets
The Ministry of Forestry argues the areas earmarked for exclusion are already degraded and no longer meet TRHS criteria.
"We propose removing them because they no longer meet the requirements of the TRHS. The TRHS forests are supposed to remain pristine, home to tigers, elephants and orangutans. In Sekincau, that is no longer the case," Satyawan said.
Government data estimate that more than 235,000 hectares (580,700 acres) across TRHS parks are degraded, including 52,715 hectares in Suoh and Sekincau.
To compensate, officials propose adding around 236,000 hectares (583,000 acres) from other protected areas, including the Rawa Singkil Wildlife Reserve in Aceh and protected forests in the Leuser ecosystem. If approved, the TRHS area would slightly increase overall to 2.6 million hectares 96.4 million acres).
The government insists the reduction will not diminish OUV, saying "all types of ecosystems and important habitats still exist" in the remaining area.
But a visit by IUCN experts in October 2024 concluded the approach was "not an appropriate basis" for a boundary change.
This is because World Heritage boundaries can't simply be traded hectare-for-hectare, since OUV is tied to unique ecological values that can't be replicated elsewhere, the IUCN experts wrote in their recommendation.
Furthermore, even if parts are degraded, they often remain part of species' home ranges and ecological networks.
The mission therefore recommends managing such areas as buffer zones with restoration programs rather than handing them off completely for development, because they still contribute functionally to the property's long-term conservation.
Civil society backlash
Conservationists and watchdogs say the government's rationale doesn't hold up – and risks setting a precedent for weakening protections nationwide.
"We deeply regret this step by the Indonesian government. It confirms suspicions that conservation regulations are being weakened to make way for extraction activities like geothermal," said Timer Manurung, executive director of Auriga Nusantara.
He compared the move to the downsizing of Raja Ampat's UNESCO Global Geopark to permit nickel mining.
"Now we are seeing a similar step being taken with Sumatra's forests," he said.
The Center of Economic and Law Studies (CELIOS), a Jakarta-based think tank, said the boundary change could damage Indonesia's credibility as a climate leader ahead of COP30 in Belem, Brazil, this November.
"Instead of reinforcing its Paris Agreement commitments and the FOLU Net Sink 2030 target [Indonesia's climate policy], Indonesia risks showing that investment interests take precedence over environmental protection," CELIOS researcher Atina Rizqiana said.
Corporate interests
At least one company is waiting for the green light. PT Star Energy Geothermal Suoh Sekincau (SEGSS), a subsidiary of publicly listed PT Barito Renewables Energy (BREN), holds a permit to explore geothermal resources in the Suoh and Sekincau area.
The permit, first issued in 2018, only covers early exploration and doesn't authorize full-scale development, which is contingent on UNESCO approving the boundary change. SEGSS also hasn't secured the required environmental impact assessment (AMDAL).
CELIOS noted that geothermal projects often bring limited local benefits. A 2025 study it conducted on the Ijen geothermal project found it employed just 0.85% of the local workforce despite a large working-age population. In East Nusa Tenggara, CELIOS estimated the Ulumbu project could reduce provincial GDP by 368 billion rupiah ($22 million) due to lost agricultural productivity.
"Agriculture is the backbone of livelihoods in Suoh and Sekincau, so geothermal projects pose a direct threat to community welfare," Atina said.
Therefore, Timer questioned who will ultimately benefit from the boundary change and geothermal development.
"The key question is: geothermal for what, owned by whom and for whose benefit? The government must be transparent so it's clear whether development is for the public good or the profit of a few."
What's at stake
For conservationists, the risks extend beyond biodiversity loss.
"Altering World Heritage boundaries for extractive projects like geothermal in TRHS not only threatens ecosystems and local communities but also risks damaging Indonesia's standing in global diplomacy," Atina said.
Indonesia has long positioned itself as a leader in climate and biodiversity talks. But critics say carving up World Heritage forests for energy projects would look like greenwashing, undermining its credibility just as it seeks more climate finance and partnerships.
If the government is serious about meeting its energy transition targets, there are still many other renewable energy options that remain underdeveloped, such as solar, wind and even wave energy along coastal areas, Ki Bagus said.
"We should ask: Why was this area designated protected in the first place? Because its values are irreplaceable elsewhere," he said as quoted by local news.