Inside KOMIPO’s remote Tanggamus Hydropower Plant in Indonesia

Korea Midland Power's (KOMIPO) Tanggamus Hydropower Plant in Sumatra, Indonesia / Courtesy of KOMIPO

TANGGAMUS, Indonesia — The journey to Korea Midland Power’s (KOMIPO) Tanggamus Hydropower Plant begins at an airport in Lampung Province, Indonesia, a region just an hour’s flight from the country’s capital Jakarta. The final 150 kilometers from there is a two-hour ride over turbulent off-road tracks, traversing remote backcountry where villagers remain largely untouched by urban civilization.

The plant sits deep in a mountainous forest accessible only by narrow, dusty roads, and operates two 27.7 megawatt units around the clock for a total of 55.4 megawatts — enough to run 56,000 wall air conditioners for an hour — drawing water from the Semangka River.

Operating since 2018 after two and a half years of construction, Tanggamus marks the company’s second hydropower plant following Wampu Hydropower Plant located in the northern part of Sumatra, which opened in 2016 as the first overseas hydropower plant commercially operated by a Korean power company.

Unlike traditional dams that rely on dramatic drops to generate power, Tanggamus uses a diversion method, channeling water for about 10 kilometers to reach a turbine that extracts energy before returning it back to the river. This approach, though technically demanding, minimizes environmental disruption, helping Indonesia to meet its renewable energy targets while securing carbon credits for Korea.

“Here, the key is that we don’t waste a single drop. After the turbines turn, all the water goes back to the main river, making it truly eco-friendly,” said Park Byeong-seok, the plant’s operations manager, while giving a tour around the plant on June 30.

An overview of the weir and intake part of Tanggamus Hydropower Plant in Sumatra, Indonesia / Joint Press Corps

Located 200 meters above sea level, the plant faces frequent sediment buildup that interrupts stable power generation and affects the reservoir’s storage capacity by 80 percent. The plant includes a sand trap to filter out sediment before water reaches the turbines and will also use amphibious excavators to help recover the financial loss from reduced capacity. For floating debris on the dam’s surface such as branches and leaves, the plant hired local workers to routinely collect those from the reservoir to help maintain operations, a move that also offered reliable jobs to local villagers.

Building the Tanggamus plant was no small feat. The project began in 2011, with construction spanning 2015 to 2018. Workers carved access roads through dense jungle, often paving sections as they went.

“When they first started, the last 14 kilometers before the site was pure jungle. So the team had to build the road as they went … and with building transmission towers, whenever rain caused some to collapse, they had to rebuild them, which was truly exhausting,” said the plant’s president and director, Kim Yun-ki.

“Tanggamus is a predominantly mountainous region, with villages sparsely scattered … which is better suited for small, distributed hydropower operations. So we decided to take the challenge. Because it’s possible to generate profits with a relatively small investment and the risk is much lower.”

Park Byeong-seok, Tanggamus Hydropower Plant operations manager, speaks while giving a tour around the plant on June 30. Joint Press Corps

While building and operating Tanggamus plant, the company has also contributed to the local community with employment opportunities and infrastructure improvements such as paved roads, solar-powered streetlights and school buses, as well as support for wildlife protection and assistance for families affected by flooding.

The plant is a financial success, serving as a cash cow for KOMIPO’s overseas portfolio. It generated 265 billion won ($192.6 million) in revenue last year with 4.6 billion won in net profit.

The plant’s transmission network, consisting of approximately 112 towers, was constructed and integrated directly into Indonesia’s state electricity company PLN’s grid. As a result, electricity generated at Tanggamus is distributed throughout Sumatra, mainly in the Lampung region.

The success of Tanggamus has paved the way for further investment in Indonesian hydropower. KOMIPO was recently named the preferred bidder of another government-led hydropower project, Siborpa in Sumatra, for which the company proposed to build a 114 megawatt capacity plant, larger than the Wampu and Tanggamus plants combined.