Theun-Hinboun Dam Hydropower Info by Hobo Maps - Go to Hydropower Projects Page - - - Home

The first hydropower plant of the Theun Hinboun Power Company (THPC) is located in both Bolikhamxay and Kammouane Provinces in Lao PDR with commercial operation started in 1998 under a 30-year BOT “build–operate–transfer” agreement with option for a 10 year extension. After the concession period the plant reverts to the Lao government.

The Project is located about 100 km upstream from where the Nam Kading (river) joins the Mekong near Pak Kading.

Theun Hinboun Power Company is owned by Electricité du Laos (EDL GEN) as the 60% major shareholder with the remaining shares evenly distributed between Norwegian Statkraft SF and GMS Lao Company Limited.

Direct shareholder investment in this project represented about 30% of total project cost while the remaining 70% was raised from international private banks.

The run-of-river project has a capacity of 220 MW and can generate up to 1,100 GWh per year, 95% of which is to be purchased by Electricity Generating Authority of Thailand (EGAT).

A weir style dam holds back water in a head pond on the Nam Theun (river). Two underground tunnels carry water from the head pond down to a power station located in Na Hin town far below.

Theun-Hinboun original weir and head pond images below at coordinates 18°15'39.6"N 104°33'43.2"E (18.261, 104.562):

Images for Theun-Hinboun Expansion dam on Nam Gnouang below at coordinates 18°17'45.6"N 104°38'09.6"E (18.296, 104.636):

Satellite image below shows both dams - original weir and expansion dam:

Satellite image below shows Na Hin town and powerhouse:

The initial project is a 220 MW trans-basin water diversion project that cost $260 million to construct.

Asian Development Bank (ADB) loaned $60 million to implement this first joint-venture hydropower project between govt. of Laos and foreign investors. The project is the first non-recourse financed public-private partnership project in Lao PDR.

The Theun Hinboun hydropower project is considered a commercial success and yielded good dividends and royalties over the first decade.

Theun-Hinboun Powerhouse images below at coordinates - 18°12'36.6"N 104°32'19.6"E (18.210176, 104.538788):

Expansion Project 2012: After a decade of operation it was decided to expand the project to a new total capacity of 500 MW by constructing a dam on the Nam Gnouang (river) which is a tributary river to the existing project. A total of 440 MW is be sold to EGAT and the remaining 60 MW sold to Electricité du Lao (EDL).

The new Nam Gnouang dam, 20 kilometers upstream from the existing Theun-Hinboun Weir Dam, created the new Nam Gnouang Reservoir for storage and to regulate river flows into the rather small Theun-Hinboun headpond. The expansion also included a 900-meter long penstock and new transmission line to Thailand beside the existing line.

The Nam Gnouang Dam structure is 480 meters wide and 65 meters high and has five gates that are opened only to discharge water to avoid flood events. The net head is only 47 meters. In normal operation the dam channels almost all water through the Nam Gnouang Powerhouse (expansion) which generates up to 60 MW of electricity. This expansion project output is not for export but for domestic supply to Electricité du Laos (EDL).

Both of the Expansion Project new powerhouses were commissioned in late 2012 and the project was inaugurated in January 2013.

Images for Nam Gnouang reservoir and intake structure below:

From the Nam Gnouang Powerhouse the water flows into the Nam Theun (river) and into the existing head pond at the original Theun-Hinboun Weir/Dam. A new intake and tunnel system channels water to an expanded Theun-Hinboun Powerhouse 240 meters in elevation below in Na Hin town in the Khounkham valley.

There a new 220 MW Francis Unit turbine operates alongside the existing two 110-MW turbines. These give Theun Hinboun Power Company an export capacity of 440 MW which is sold to Thailand through two 230 kV transmission lines. The total combined generating capacity is now 500 MW with much of the water from the new Nam Gnouang reservoir used to generate power twice.

The water released from the Na Hin powerhouse flows to a spillway and into a regulating reservoir before final release into the Nam Hai (river), a tributary of Nam Hinboun which flows into the Mekong.

Theun-Hinboun Hydropower Project layout in image below after the expansion project:

Theun-Hinboun Layout below:

Images below show upgrade of facilities project adding an additional 20 MW capacity:

Powerhouse interior image below:

Theun-Hinboun Control Room 1 image below:

Three different styles of generators and a rotor at Theun-Hinboun shown below:

Image below is view over powerhouse eastward towards Kong Lor Cave area.

Theun-Hinboun Switchyard 1 image below:

Theun-Hinboun Switchyard 2 image below:

Location map below shows Theun-Hinboun Projects at the top in gray and pink ovals:

See our map of Nam Theun Basin and Nam Hinboun Basin water drainage and catchment areas HERE

Cooperative Muratori & Cementisti C.M.C di Ravenna & Right Tunneling were contractors involved in the expansion project. Ttunnel-boring machine breakthrough image below after nine months of boring 6.9 meter diameter tunnel from intake pond to powerhouse.

Theun-Hinboun tunnel diagram below:

Nam Gnouang reservoir total storage capacity is about 2,900 million cubic meters while effective active capacity in chart below is 2,262 million cubic meters.

440 MW of Theun-Hinboun's output is for export to Thailand by the route shown in map below: See enlarged version HERE.

Theun Hinboun Expansion reservoir image below as of Oct. 2022 at end of rainy season:

Theun-Hinboun can be pronounced like "Tehn hin boon".