The Project’s location is extremely favorable for a large-scale, world-class hydroelectric power facility. The natural geography of the Nakai Plateau and the surrounding area is unique in that it allows a hydroelectric project with a significant head of water without a corresponding requirement for a high dam.

Accordingly, the Project is designed to make optimum use of this unique topographical situation. It is a trans-basin scheme composed of various features located in three provinces of central Laos (primarily in Khammouane province, with some features located in Bolikhamsay and Savannakhet provinces). Bordering the future reservoir and plateau area, the catchment area is mostly covered with pristine primary forest and comprises part of the Nakai-Nam Theun National Biodiversity Conservation Area (“NBCA”). This 4,013 km2 area of outstanding natural beauty and global importance has been the subject of extensive studies and will be entirely protected thanks to partial funding to be provided by the Project.

The Project is to be built on the Nam Theun River, a tributary of the Mekong. Its key features include:
a 39m high concrete gravity dam with integrated spillway;
a 450 km2 reservoir (at Full Supply Level) and active storage of 3,530 million m3;
a catchment area of 4,013 km2;
an average net head of water of 348 m;
a powerhouse comprising 4 x 250 MW Francis turbines (for supply of power to EGAT) and 2 x 43 MW Pelton turbines (for supply of power to EDL) generating a total of 6,000 GWh per year;
a 78 km long double circuit 125 kV transmission line to Thakhek;
a 138 km long double circuit 500 kV transmission line to the Thai border; and
a 160 km long double circuit 500 kV transmission line from the Thai border to Roi Et (to be built and funded by EGAT).