Singkarak hydroelectric plant

Name of Project:

Singkarak hydroelectric plant



Country:
Indonesia

Client:
Perusahaan Umum Listrik Negara (PLN)

This hydroelectric plant diverts almost all the rainwater from the drainage basin of Singkarak Lake through the Barisan mountain range, which lies west of the lake in the province of West Sumatra. After being used to produce electrical power, the water is discharged into the Anai River, which flows into the sea.

The underground power plant and its tunnels are located close to the confluence of the Anai and Asampulau Rivers, about 40 km northeast of the city of Padang, the regional capital and chief port of the province, and about 10 km east of the nearest city, Lubuk Alung.

The plant's intake structure, however, is located in the vicinity of the town of Malalo on the western bank of Singkarak Lake, about 7 km from its northern end.

The main features of the project, split into two contracts, both of which awarded to the Joint Venture, are listed below.

  • Dam on the Ombilin River, on the eastern shore of the lake;
  • Intake structure on the western shore of the lake;
  • 16,500 m long headrace tunnel, of which 7,000 m excavated with a Robbins drilling rig with an overall cross-section of 5 to 5.30 m in diameter;
  • Pipeline bridge on the Asampulau Sani River;
  • Three access tunnels to the headrace tunnel (only one temporary);
  • Diversion of the Buluh River:
  • intake structure on the Buluh River;
  • underground sediment trap and corresponding tunnels;
  • diversion tunnel;
  • Surge tank at the top of the penstock and upper and lower expansion chambers;
  • Underground penstock, angled and reinforced, 310 m long and 4.1 m in diameter;
  • Reinforced 45° angle tunnel, 90 m long and 4.1 m in diameter;
  • Reinforced collector;
  • Underground power plant, 21-25 m wide, 30-37 m high, and 90 m long, to house four turbines for a total installed capacity of 175 MW, transformers, and related installations;
  • Access tunnel approximately 850 m long, 5 x 5 m parking area;
  • Auxiliary tunnel approximately 1.4 km long and inclined cable chase 80 m long, for wiring and emergency equipment;
  • A tailrace tunnel 1.8 km long;
  • Exit portal and tailrace channel for return to Anai River;
  • Control and utility building;
  • Singkarak substation;
  • Access roads and bridges;
  • Transmission lines;
  • Expansion of the Lubuk Alung substation.
Principali dati tecnici:
Earth excavation: 415,000 m3
Underground excavation: 737,300 m3
Embankments: 182,000 m3
Surface concrete: 18,500 m3
Underground concrete: 210,000 m3
Gunite: 50,000 m3
Anchors and bolting: 234,165 m.
Reinforcing iron: 760 t.

Last update: 18/09/2013