Nam Ngum 3

Nam Ngum 3 Hydropower Project (NN3 Project) is located on the middle reach of Nam Ngum River which is the main tributary of MeKong River at a distance of approximately 180 km by road north east of Vientiane . A high Roller Compacted Concrete Dam will be built across a deeply entrenched section of the Nam Ngum River just above its confluence with Nam Pha to create a reservoir which will divert flow via a single pressure tunnel to a power station situated 330 m below the reservoir on the lower Nam Ngum giving a net head of 302 m. Large catchments area of 3,888 Km2 will provide more than 3000 MCM for an annual runoff. NN3 power station with accommodation of 2 x 220 MW generators will be able to generate electricity of more than 2200 Gwh/year.

 

PROJECT STATUS in short

•  MOU signed in March 1994.

•  Project Development Agreement signed in November 1997.

•  The technical feasibility study had been carried out in 1996 and updated in 2001.

•  Environment Impact Assessment (EIA) was completed in 1998 and in May 2003 the NN3 Social Action Plan and Environment Management Plan had been approved and the environmental compliance certificate had been issued by Science Technology and Environment Agency (STEA) of the Government of Lao PDR to MDX Lao.

•  New Tariff MOU with EGAT signed on 18 th December 2006.

 

Catchments

Area

3,888 km2

Annual Runoff

3,163MCM

Reservoir

Full Supply Level (FSL)

EL 720m

Minimum Operating Level (MOL)

EL660m

Storage at FSL

1,316MCM

Storage at MOL

337MCM

Surface area at FSL

25.6 km2

1 in 10,000 flood inflow

 

PMF inflow

6,316 m 3 /s

Dam

Type

Roller Compacted Concrete Dam

Crest level

EL 730m

Height

220m

Crest length

600m

Volume

3.3 MCM

Power tunnel

Diameter

7.5m

Length

10.8km

Lining

Concrete

Underground powerhouse

Turbines:

 

No. of units

2

Installed capacity

440MW

Type of turbine

Francis, vertical

Rated head

302m

Design discharge

163 m 3 /s

Transmission System

230 kV, NN3 – ISS (2 x 1272 MCMACSR)

105km (in Lao PDR)

500 kV, ISS – Border

27 km (in Lao PDR)

No. of circuits

2

Access road

Length of new road

26km

Length of road needing upgrading/maintenance

116km