Nam Emoun Dam Hydropower Project info by Hobo Maps - Go to Hydropower Projects Page - - - HOME

Nam Emoun (Emoon or E-Moun) Hydropower Project was also known as Dak E Meule, Dac E Meule, Dakemeule, Houay Emun, Emoon or E-Moun.

The project is located on the Nam Emoun and Houay Het rivers, about 30 kilometers north-east of Sekong town in Sekong province of southern Lao PDR. The project site is near Dok Cham Village in Dak Cheun District about 30 km from the Vietnam border by direct line.

The powerhouse location seen in satellite images below is at coordinates 15°34'27.8"N 106°58'09.8"E (15.574400, 106.969400):

The Nam Emoun Hydropower project started construction in 2019 and was finished in 2024. The reservoirs started impounding in March 2022. The First Spin turbine test was a success in February 2023. The project was completed in late 2023 and in May 2024 the transmission line to Vietnam was completed. Export of output power to Vietnam is now in progress in 2026.

Chaleun Sekong Energy Co., Ltd. (CS Energy) in 2026 is the 100% owner and manager of the project. Vietnam-based Songda 5 Company was a main contractor.

The Houay Het river is a main tributary of the Nam Emoun river which is a main tributary of the Sekong (Xekong) river. The Houay Het river has a rather small catchment area of 254 square km at the diversion dam site and the Nam Emoun river has an even smaller catchment area of 208 square km at the main dam site.

The project has 20.5 km of tunnels dug with tunnel-boring machines (TBM) with final breakthrough in August 2021.The estimated routes of the tunnels with two main diversions are seen in the project layout map below:

Nam Emoun HPP generating capacity is 133 MW from two vertical Pelton turbines with 501 GWh annual output capability.

The project was expected to cost about US$ 235 million.

Nam Emoun hydropower project layout image below rotated with north pointing upward:

Nam Emoun HPP administration area images below at coordinates - 15°30'01.9"N 107°00'16.9"E (15.500528, 107.004694)

Nam Emoun powerhouse area images below:

Nam Emoun penstock images below:

The project has sand removal structures at both the Main Dam and at the Houay Het Diversion Dam as seen in images below. Probably needed due to long tunnels that carry diverted water to the surge tank and powerhouse. We rarely see sand removal structures like these in other Lao hydropower projects.

Nam Emoun Main Dam image below at coordinates - 15°33'19.0"N 107°01'35.0"E (15.555278, 107.02638).

Main Dam site images below include the sand removal structure:

The project includes a Diversion Dam, Main Dam, Waterway Channels, Conveyance Tunnel, Headrace Tunnel, Surge Tank, Vertical Well, Penstock, Powerhouse, Switchyard, Tailrace Channel and a 230 kV transformer station with 53 km of dual circuit high-voltage transmission power lines.

One of the dams features a strong CVC (Compacted Vibrated Concrete) reinforced concrete structure.

Houay Het Diversion Dam images below with sand removal structure at coordinates - 15°26'26.4"N 107°00'58.5"E (15.440667, 107.016250):

Nam Emoun powerhouse interior images below:

Nam Emoun stator installation image below:

Nam Emoun Unit 2 Rotor-Lifting Ceremony image below:

Nam Emoun controls images below:

Nam Emoun Project statistics below: note very small catchment areas and reservoir storage capacities.

The Rated Head below of 397 meters is compared to a Gross Head of 415.9 meters in a later report.

Power Transmission To Vietnam:

The project includes construction of a single circuit high-voltage power transmission line from the project to the Vietnam border. The length of the transmission line from the Nam Emoun Power Station to the Dak Ock Substation in Quang Nam Province of Vietnam is 67 kilometers.

Electricity of Viet Nam (EVN) agreed to purchase the plant's output pursuant to a Power Purchase Agreement (PPA) signed on 4 January 2020.

On 31 March 2022 Electricity of Vietnam Power Project Management Board 2 (EVNPMB 2) organized the signing of Contract "Engineering Procurement and Construction (EPC)" project of Dak Ooc 220 kV switching substation and 220 kV power lines connecting Nam Emoun Hydropower Plant (Laos) to the Vietnamese power grid system. On 28 May 2024 this transmission line was completed and energizeed. Exports of power to Vietnam began in January 2025.

The power transmission project operates according to a bilateral agreement between the Governments of Vietnam and  Lao PDR. The transmission project inside Vietnam is invested by EVN and managed by EVNPMB 2.

Transmission project images inside Laos below:

Nam Emoun Hydropower construction site image below: See powerhouse way down below with red roof.

Maps below show route of 220 kV transmission line to Vietnam.

Original reports had NEM HPP Company Ltd. as the owner and developer of the project with Chaleun Sekong Energy Co., Ltd. (CS Energy) as the major shareholder. Later reports have CS Energy alone as owning and developing the project. Vietnam-based Songda 5 Company was a main contractor.

Project history below from CS Energy website November 2021 plus additions by us in 2023:

  1. Original developer signed a Memorandum of Understanding (MOU) with the Government of Lao PDR.
  2. Project Development Agreement (PDA) was signed in July 2015
  3. CS Energy took over development and construction of the project on 2 June 2017
  4. The Feasibility study of the project was approved in December 2017
  5. Completed the report of Environmental and Social Impact Assessment in November 2017
  6. Completed the Environmental and Social Management and Monitoring Plans in July 2017
  7. Completed the Environmental and Social Management and Monitoring Plans-construction Phase in December 2018
  8. Completed the preparation of biomass removal plans and approved the plans for November 2019
  9. Signed a power purchase agreement (PPA) with the Electricity of Vietnam (EVN) on January 04, 2020
  10. Signed a concession agreement with the Government of Lao PDR on December 25, 2020
  11. In 2013, a preliminary survey was conducted by GXED & CGGC, the original owner of the project, TK Group.
  12. In 2015, the project proposal presentation was submitted by GXED.
  13. In July 2015, the project proposal presentation was inspected by Poyry Energy Ltd
  14. In 2016, the project owner was changed to Chaleun Sekong Co. Ltd.
  15. In April 2019, a project construction consulting contract was signed with ILF Consultant Engineering
  16. In December 2018, Song Da-5 Joint Stock Company signed a contract for civil and hydropower work.
  17. In April 2019, Voith Hydro Shanghai signed a contract for electrical and mechanical installation.
  18. In April 2019, the original design was redesigned by ILF Consultant
  19. Nam Emoun Main Dam reservoir impounding ceremony March 2022
  20. Nam Emoun spin test first Feb. 25, 2023
  21. Completion of work by Songda 5 EPC contractor in September 2023 & handover
  22. On May 28, 2024, Power Project Management Board 2 energized the 220 kV Dak Ooc switching station for connection from Nam Emoun Hydropower Plant (Laos) to the Vietnamese power system.
  23. Exports of power to Vietnam began in January 2025.

Much of the construction at Nam Emoun HPP was done by Vietnamese workers employed by Songda 5 company.

Nam Emoun location on map below at upper-right side:

 

Similar Project Names - In 2023 a new hydropower project was announced with the name Nam Emeun 1 & 2. Sadly, that name is similer to the already-completed Nam Emoun hydropower project. Very confusing with similar names and both projects located in Sekong Province.

Click HERE to see our other web page for this planned Nam Emeun 1 & 2 project that is still in the planning stage in 2026.