Nam Ngum 1 Hydro Power Plant     There have been 3552 visitors to this websiteThere have been 3552 visitors to this websiteThere have been 3552 visitors to this websiteThere have been 3552 visitors to this website 

Location: Xaysavang village, Keooudom district, Vientiane Province 

 

Tel: 023 431223

Fax: 023 431223

E-mail: namngum1_hpp@edlgen.com.la

The Nam Ngum River is one of the major rivers in the Lao PDR. It offers a hydropower potential up to 1,600 MW from various possible sites. NNG1 HPP has an installed capacity of 150 MW. In the year 2003-2004, a rehabilitation project was implemented on two of the units in NNG1 HPP and it has increased the installed capacity of those units. At present, the NNG1 HPP has installed capacity of 155 MW. The NNG1 HPP is located about 90 km to the north of Vientiane Capital City. NNG1 HPP construction project has been developed into 3 phases as follows:

Phase I

  Phase 1 of NNG1 HPP was commenced in 1968 and was commissioned in 1971 at the cost of USD 28 million. The facilities in this phase include a gravity concrete dam, a power plant at the base of the dam with two 15 MW generating units and provisions for 3 additional units. The generation units supply to EDL’s single circuit high voltage transmission line, with transmission capacity of 115 kV, from Nam Ngum site through Vientiane Capital City at Phonetong Substation to EGAT’s grid at Nongkhai (Thailand) Substation.

Phase II

  Phase II of NNG1 HPP began its activities in 1976 and was successfully commissioned in 1978 at the cost of USD 49 million. The facilities in this phase includes installation of spillway gates, new penstocks and intake gates, an extension of the powerhouse to accommodate three new generating units of

40 MW each, connecting to EDL’s double circuit high voltage transmission lines, with transmission capacity of 115 kV, from NNG1 HPP site through Vientiane Capital City at Phonetong Substation to EGAT’s grid at Udone 2 (Thailand) Substation.

Phase III

  Phase III of NNG1 HPP began its activities in 1983 and was successfully commissioned in 1984 at the cost of USD 20 million. The 40 MW generating unit was installed in order to fully utilize the hydro potential and facilities which are already installed. After the completion of this phase, the average annual energy production is 865 GWh.

Nam Song Diversion and Nam Leuk Hydropower Plant

  The addition of Nam Song Diversion Project to NNG1 HPP reservoir in 1996 has increased the average annual energy production of NNG1 HPP up to 995 GWh. Moreover, the completion of Nam Leuk Hydropower Plant has increased the average annual energy production of NNG1 HPP up to 1,025 GWh.

Summary of Principal Technical Data of NNG1 HPP

1. Capacity

Total installed capacity

Number of Units

 

: 155 MW

: 5 Units;

  2 Units x 17.5 MW

  3 Units x 40 MW

Average energy production : 1,025 GWh/year

2. Storage

Catchment area

Full water level

Low water level

Normal maximum water level

Reservoir surface (at El. 212.00)

Storage capacity

Active storage

 

: 8,460 km2

: 212.30 masl

: 196.0 masl

: 213.0 masl

: 370 km2

: 7,030 x 106 m3

: 4,700 x 106 m3

3. Tailrace

Minimum tail water level (Q=0)

 

: 164.0 masl

4. Dam

Type

Length

Height

Width

 

: Concrete gravity

: 468 m

: 70 m

: 6 m

5. Spillway

Type of gate

Number

Width x Height

 

: Radial

: 4 Nos.

: 12.5 m x 10.0 m