Nam Sim Dam Hydropower Info by Hobo Maps - Go to Hydropower Projects Page - - Home

Nam Sim also spelled Nam Xim sometimes

Nam Sim (river) is located in Houaphanh Province, northern Lao PDR and forms part of the Nam Ma basin which has its source near the border of Laos and Vietnam. The project is located about 20 km southeast of Vieng Xay and close to National Road 6. The Nam Sim is a tributary of the Song Ma river, originating in the Annamite Range in Lao PDR and flowing eastwards into Vietnam where it enters the Gulf of Tonkin at Thanh Hoa.

Nam Sim Dam structure image below under construction:

The project is located downstream of the village of Kangmuang village, about 1.5 km downstream from the joining of the Nam Sim and Nam Vong rivers in Vieng Xay District.

Geographic coordinates of the project are: Power House 20.3585°N 104.3868°E (20.358500, 104.386800) and Main Dam Site 20.3459°N 104.3810°E (20.345900, 104.381000).

Nam Sim Powerhouse and Dam sites shown together on image below:

The project is a run-of-river type with a small reservoir and some daily regulation. The catchment area for the Nam Sim is 197 square km.

The dam has a free-overflow spillway and maximum reservoir surface area of 3 hectares.

The project consists of a small dam to capture and divert the streamflow, a headrace canal and steel penstock to convey the water to a powerhouse and two horizontal Francis turbine units to generate electricity. The gross head of the dam and river gradient is about 170 meters. 

The project includes a 10 meter high weir, a 1.1 km long tunnel, a 500 meter long penstock and a power plant with two Francis turbines for a total 9 MW capacity and 32.5 GWh annual production capacity.

The power generated is transferred to a 22 kV transmission line approximately 5 km in length connected to the Lao grid. Electricite du Laos (EDL) is to buy all power produced for local distribution.

Nam Sim Powerhouse site shown on image below at coordinates - 20.3585°N 104.3868°E (20.358500, 104.386800):

Nam Sim Dam on satellite image below at coordinates - 20.3459°N 104.3810°E (20.345900, 104.381000):

The project was estimated to cost about US$ 18 million. Funding was aided by a US $6 million grant from the Norwegian Agency for Development Cooperation and a loan from Norfund and Finnfund development finance companies.

The project operates under a 25 year concession agreement .

Nam Sim Power Company is the project owner. It originally was a joint venture between the French MECAMIDI-Norpower which held a 75 percent share and Lao Electrical Construction and Installation State Enterprise holding a 25 percent share on behalf of the Lao government. Norfund and Finnfund have later taken over the shares from French MECAMIDI-Norpower and now own 75% of the project.

Project data charts below:

Main contractors at Contract signing: MECAMIDI SA, a company incorporated under the laws of France and General Lung Lo Construction Company - Ministry of National Defense (Vietnam).

Investor: Nam Sim Company Limited, a limited liability company incorporated under the laws of Lao PDR.

Groundbreaking Ceremony held in 2013 at start of construction.

Nam Sim project site image below:

Nam Sim components delivery image below:

The Nam Sim Hydropower project is designed to qualify as a greenhouse-gas-reducing CDM (Clean Development Mechanism) project under the Kyoto Protocol that may result in CO2 emission reduction, as it may displace power generation that otherwise would be based on burning of fossil fuels. Carbon dioxide emission reductions were estimated to be 17,995 tons per year for this project. View or download CDM application document HERE .