Design aspects

You are here: Home>>Introduction>>Nam Theun 2>>Design

The Contested Landscapes of the Nam Theun, Lao PDR
Australian Mekong Resource Centre

Design aspects

The design of 908 MW Nam Theun 2 hydropower project involves an inter-basin transfer scheme, perhaps the most destructive of possible hydro schemes. Nam Theun 2 will divert river flow from the Nam Theun into another river system, the Xe Bang Fai via a discharge channel. The diversion of over 200 cubic meters per second of river flow will reduce downstream flows in the Nam Theun by a corresponding amount. The reduction in river flow is compounded by the downstream Theun Hinboun hydro project, another inter-basin hydro scheme which will further reduce flows in the downstream Nam Theun and Nam Kading resulting

map.gif (43086 bytes)

in severe negative impacts on the river ecology and the people that rely on the river for their sustenance and livelihoods.

   tunnel.jpg (20330 bytes)
    Photo: Andrew Wyatt
    A 700 m long exploratory shaft at the site of the
    Nam Theun 2 power station. The tunnel extends
    horizontally into the base of the Nakay Escarpment.

The choice of an inter-basin scheme was made to take advantage of a 355 m head from the Nakay Plateau to the base of the Nakay Escarpment to generate 908 MW of electricity with a relatively low dam wall of 50m.

Despite the low dam wall, the dam will produce a reservoir of approximately 450 square kilometres because it lies on the relatively flat Nakay Plateau. The reservoir will flood agricultural and forested land, and displace 16 villages consisting of approximately 1000 families.

Source: NTEC
Diagram of the Nam Theun 2 hydropower scheme highlighting the inter-basin transfer to the Xe Bang Fai river and the large hydraulic head available over the Nakay Escarpment