Bakun Hydroelectric Dam, Sarawak

Location : Sarawak, Malaysia

The Bakun Dam is an embankment dam located in Sarawak, Malaysia, on the Balui River, a tributary or source of the Rajang River and some sixty kilometres west of Belaga. As part of the project, the second tallest concrete-faced rockfill dam in the world would be built. It is planned to generate 2,400 megawatts (MW) of electricity once completed.

Future plans for the dam include connecting it to an envisioned Trans-Borneo Power Grid Interconnection, which would be a grid to supply power to Sarawak, Sabah, Brunei, and Kalimantan (Indonesia). There have been mentions of this grid made within ASEAN meetings but no actions have been taken by any party. Bakun Dam came online on 6 August 2011.

As of 2015, Bakun Dam is the biggest dam in Southeast Asia.

Environmental and social damage

The Bakun dam flooding commenced on 13 October 2010 with a faulty start and will put 700 km² of land underwater – equivalent to the size of Singapore. The rainforest of this part of Southeast Asia has some of the highest rates of plant and animal endemism, species found there and nowhere else on Earth, and this dam has done irreparable ecological damage to that region.

Construction of the dam required the relocation of more than 9,000 native residents (mainly Kayan/Kenyah) of the indigenous peoples who lived in the area to be flooded. Many Sarawak natives have been relocated to a longhouse settlement named Sungai Asap in Bakun. Most of them were subsistence farmers. Each family was promised 3 acres (1.21 ha) of land but many families still have not been compensated.

Technical specifications

The permanent dam components are as follows:

• Main dam
  • Maximum height above foundation of 205 m, and crest length of 750 m, volume of fill is 16,710,000 m³.
  • Crest elevation is 235 m above sea level (ASL), maximum flood level is 232 m, operating levels maximum 228 m and minimum 195 m.
  • Reservoir area at 228 m ASL is 695 km², and with a catchment area of 14,750 km². Gross storage volume is 43,800 million cubic meters.
• Power intake structure – 8 bays with 16 roller gates.
• Gated spillway – gated concrete weir with chute and flip bucket, with capacity of 15,000 cubic meters per second.
• Power tunnels – 8 tunnels of 8.5 m diameter each with lengths of 760 m each.
• Powerhouse
  • Surface powerhouse, with 4-level measuring 250 m length × 48 m width × 48 m height
  • with 8 penstocks to powertrains comprising 8 vertical-shaft Francis turbines of 300 MW each, 8 air-cooled generators of 360 MVA each and 8 oil-immersed transformers of 360 MVA each.

(Source : https://en.wikipedia.org/wiki/Bakun_Dam)