CONTEXT:

The Batang Toru Hydropower Project would be located on the 170km long Batang Toru River in the lowlands of the Batang Toru Ecosystem, in the southern part of North Sumatra. The project was initially proposed in 2012 to meet regional energy needs and to ease Indonesia’s budgetary deficit by eliminating the need to import diesel, although the project has since been shown to no longer be needed because other energy projects had come online elsewhere sufficient to meet demand.

PROJECT IMPACTS:

Construction of the Batang Toru dam would entail significant impacts on biodiversity. The area that would be impacted by the dam consists of the last primary lowland forest of the Batang Toru Ecosystem. Even prior to the discovery of the Tapanuli orangutan as a distinct species, the area was known to harbor a high density of biological diversity. In addition to orangutans, scientists have found high numbers of other land and riparian species, including the Sumatran tiger, pangolins, and siamangs—the largest of the gibbons. The project and its related infrastructure would destroy this unique habitat and make the area more accessible to poachers and illegal loggers.

IMPACTS ON THE NEWLY DISCOVERED TAPANULI ORANGUTAN

In November 2017, shortly after construction of Batang Toru began, scientific reports revealed the orangutan species in the project area to be the Tapanuli orangutan, not the Sumatran orangutan as previously believed. The Tapanuli orangutan was a newly discovered species and distinct from the other two known orangutan species. With fewer than 800 individual Tapanuli orangutans remaining, experts immediately warned that the Tapanuli orangutan was facing imminent danger of extinction, with its prime habitat to be directly impacted by construction of the Batang Toru dam. Indeed, the Tapanuli orangutans are found only in the Batang Toru Ecosystem and live in the lowlands where the infrastructure associated with Batang Toru is to be built, and in three areas of adjacent highlands.

IMPACTS ON FRESHWATER SPECIES

As a diversion type hydropower project that would divert much of the river’s flows from the main stretch of the river, the project would effectively split the river in two, preventing fish and other species from migrating upstream or downstream. Species distribution, access to spawning grounds, reduced habitat area, isolation of populations, and erection of a permanent barrier will significantly impact freshwater species and river ecology as a whole.

Biodiversity Snapshot

Scientists have found over 310 species of birds, 80 species of reptiles, 64 species of frogs and toads, and more than 1,000 tree species in the Batang Toru Ecosystem. The botanical survey conducted for the project found a new species of myco-heterotrophic plant and evidence of Dipterocarpus Cinereus, a tree thought to be extinct. Batang Toru is one of the few areas in the world where three ape species coexist within the same geographical range. A number of species identified in the project area are on the IUCN Red List, among them:

CRITICALLY ENDANGERED

Sumatran tiger

Sumatran orangutan

Tapanuli orangutan

Pangolin

ENDANGERED

Siamang

Asian tapir

Mitred leaf monkey

Agile gibbon

VULNERABLE

Pig tailed macaque

Tapanuli Orangutan:

The world’s most recently discovered and rarest ape

It is rare to discover new mammal species that are as large as orangutans. The last discovery of a great ape species was in 1929. The 767 remaining specimens of Tapanuli orangutan are exclusively located in the forests of the Batang Toru ecosystem, in a range of less than 1000km². While the Tapanuli orangutan is officially the newest recorded ape species, DNA studies show that the Tapanuli is actually the most ancient among orangutan species.

Like all orangutans, the Tapanuli move more easily in the trees than on the ground. While they tend to be solitary and build a new nest each night, the females in particular tend to return to home ranges, even when parts of the area are destroyed. Orangutans are only found in the wild in Indonesia and Malaysia, and all three subspecies are considered critically endangered and their populations are declining. The primary causes are habitat loss from palm oil plantations, mining, and infrastructure, as well as the induced impacts such as hunting that these activities bring. The Tapanuli orangutans are by far the rarest and most imminently in danger of extinction.

AT-RISK SPECIES PROFILE

PROJECT IMPACTS

LESSONS

Company: Power China

Subsidiary: Sinohydro

Impact Category

Critical Habitat

Impact Category

Great Apes

Impact Category

Biodiversity Hotspot

CAPACITY

510 MW

The energy that would be generated is no longer needed because other energy projects are online.

COST

$1.6 billion​

STATUS

Under Construction​

Construction started in 2017 before halting in September 2019. Construction is understood to have since resumed.

BATANG TORU

North Sumatra, Indonesia

Construction of the Batang Toru dam could precipitate the first extinction of a great ape species, the Tapanuli orangutan. 

Critically endangered Sumatran Orangutan

Image by Helga Gubatz

Batang Toru River

Image by Ayat S.; Sourced from Mongabay

Critically endangered Sumatran Tiger

Image by Martina P.

Biodiversity Snapshot

Scientists have found over 310 species of birds, 80 species of reptiles, 64 species of frogs and toads, and more than 1,000 tree species in the Batang Toru Ecosystem. The botanical survey conducted for the project found a new species of myco-heterotrophic plant and evidence of Dipterocarpus Cinereus, a tree thought to be extinct. Batang Toru is one of the few areas in the world where three ape species coexist within the same geographical range. A number of species identified in the project area are on the IUCN Red List, among them:

CRITICALLY ENDANGERED

Sumatran tiger

Sumatran orangutan

Tapanuli orangutan

Pangolin

ENDANGERED

Siamang

Asian tapir

Mitred leaf monkey

Agile gibbon

VULNERABLE

Pig tailed macaque

1.

Discovery of a new and critically endangered ape species within the project area should have prompted PCR to immediately halt construction and consider withdrawal from the project.

2.

Even prior to scientific confirmation of a new orangutan species, the known presence of orangutans (all of which are critically endangered) should have prompted a rigorous assessment aligned with IFC Performance Standard 6 to determine whether it would be possible to achieve no net loss of orangutan populations in the project area.