Upstream side aerial view of the Nam Theun 1 dam and the downstream valley

Nam Theun 1 Hydropower Project, Laos

Providing clean energy through hydropower, Laos is becoming the "Battery of Southeast Asia"

Nestled in the heart of Laos, the Nam Theun 1 Hydropower Project (NT1HPP) is a key component in the country's vision to become the "Battery of Southeast Asia". AFRY has played a pivotal role in the project's success, showcasing unparalleled dedication, securing world speed records in dam construction, and reaching other new achievements in roller compacted concrete (RCC) dam construction by applying unique and innovative ideas.

Aerial view from downstream of the Nam Theun 1 RCC Dam, power plant, and reservoir
Aerial view from downstream of the Nam Theun 1 RCC dam, power plant, and reservoir

Laos is a mountainous country in the centre of the Indochinese peninsula with the Mekong River flowing along the border with Thailand. Due to the geomorphological characteristics with rapids and waterfalls, it is difficult to navigate but at the same time it represents an enormous potential for hydroelectric power generation.

The Government of Laos is implementing a series of hydropower projects to exploit these water resources with the ambition of accelerating economic growth and becoming the "Battery of Southeast Asia". The NT1HPP is one of these significant projects and is located on the Nam Kading River in Bolikhamxay Province, 33 km upstream of the confluence with the Mekong river. The project includes a curved RCC gravity dam with a maximum height of 187 m and has a total installed capacity of 650 MW, of which 520 MW of power is exported to Thailand and 130 MW channeled towards domestic consumption to cope with the increasing energy demand.

The project has been developed by the Nam Theun 1 Power Company (NT1PC) who entered into a 27-year Concession Agreement with the Government of Laos to build and operate the plant. NT1PC also has two Power Purchase Agreements with the Electricity Generating Authority (EGAT) of Thailand, and the State Electricity Company (EdL) in Laos.

In line with their commitment to support environmentally sustainable and socially responsible national development, NT1PC confirmed AFRY as its trusted partner from the initial project development stages right through to the project management and supervision of the works until the commissioning of the hydropower plant.

Project manager standing on river's edge with power dam in background
World record team
"With roles as diverse as our heritages, we forged a team without boundaries and set new world records in dam building."

Kenneth Ross, Senior Project Manager

The AFRY project team was made up of around 60 people, with 14 different nationalities, from six continents across the world. As well as being a very culturally diverse team, our roles were also extremely varied. We had specialists in civil engineering, contracts management, quantity surveying, planning and scheduling, quality control, geology and geotechnics, tunnelling, dams, health & safety, environmental and social matters, etc.

We are proud to have been the trusted partner in this strategic project for Laos and to have completed it on time despite the unprecedented complications due to the pandemic. All this was possible thanks to a team of brave devoted team players.

Kenneth Ross, Senior Project Manager

Did you know?

Benefits for Laos

The NT1HPP project contributes significantly to Laos' economic and energy sustainability transition as well as to the security and stability of the electricity supply of the region. The hydropower project exports 520 MW of electricity to Thailand, and generates 130 MW to cope with the increasing domestic energy needs.

Setting world records in dam building

The AFRY team relentlessly pursued the project with professionalism and devotion even through the global pandemic and the ensuing lockdown. Despite that, the team managed to deliver the project on time and even broke many world records in dam construction, including the following:

  1. Most concrete ever placed in a dam of this type in one month, with a single conveyor delivery line (October 2020: 251,934 m³)
  2. Most concrete ever placed in a dam of this type in one month, with any delivery system (January 2021: 361,333 m³). This made them undisputed World Champions, at every level
  3. Placement of over 200,000 m³ of concrete in a dam of this type for 6 consecutive months
  4. Placement of over 300,000 m³ of concrete in a dam of this type, twice
  5. World’s highest ever temporary stepped spillway on a dam (operated successfully in the 2021 rainy season)
  6. World's steepest placement of concrete on a dam of this type
  7. World's highest concrete lift thickness (9 m).
Nam Theun 1 Dam sideview spillway
Nam Theun 1 Team at power intake with AFRY banner
Nam Theun 1 Team 4
Nam Theun 1 Team 3
Nam Theun 1 Team 3
Nam Theun 1 Team at power intake 3
Nam Theun 1 Team at the office
Nam Theun 1 Team at power intake hats off
Nam Theun 1 Dam sideview spillway
Nam Theun 1 Team at power intake with AFRY banner
Nam Theun 1 Team 4
Nam Theun 1 Team 3
Nam Theun 1 Team 3
Nam Theun 1 Team at power intake 3
Nam Theun 1 Team at the office
Nam Theun 1 Team at power intake hats off


What was AFRY's role in Nam Theun 1? Arrow pointing right

AFRY provided consultancy services to NT1PC, in all phases of the project and with all the required tasks, from early 2013 until 2023, whilst ensuring the successful realisation of the project. Our core services included:

  • Feasibility study
  • Social and Environmental Impact Assessment Study (ESIA)
  • Basic Design
  • Tender Design
  • Preparation of Tender Documents
  • Technical assistance during prequalification, tender evaluation and contract negotiations and until financial closure
  • Detailed design and construction design for the civil contractors
  • Project management
  • Design and construction interface management
  • Contract administration, dispute resolution and claims management
  • Construction supervision of civil structures, erection and commissioning of electro-mechanical and hydro-mechanical equipment, and transmission line works
  • Design review and approval of all project documents prepared by the hydro-mechanical, electro-mechanical and transmission line contractors
  • Health, safety and environment services
  • Project planning
  • Technical advisory services for the purpose of the implementation of the environmental and social mitigation plans
  • Technical support to Lenders, Safety Panels and Government of Laos.
What added value did AFRY bring to the project? Arrow pointing right

AFRY brought speed, innovative thinking, state of the art and thought leading ideas, pioneered new achievements and set world records in dam building, while leading the project to completion on time and on budget after working with NT1PC for 10 years.

The project is undoubtedly sustainable and in line with our corporate values. Our core activities included environmental and social services throughout, performed to the highest international standards.

What were the challenges and results of the project? Arrow pointing right

The biggest challenges were on site during the COVID 19 pandemic. We were a diverse and multicultural team made up of close to 60 ladies and gentlemen, with 14 different nationalities, arriving to work on the NT1HPP from six continents across the world (Asia, Africa, Australia, North America, South America and Europe).

A few of us commenced our journey on this huge project in 2015, and most of us remained until well into 2022. In addition to being a very culturally diverse team, our roles were also extremely varied, from project management through all technical expertise involved in the construction.

All of us were resident in Laos, living at the construction site, and formed a perfect team that became our AFRY “engine”. This AFRY “engine” powered the project into becoming a world record breaking success story, which was a result of our relentless focus, despite living under the restrictions and threats related to COVID-19 for approximately 18 months.

The brave achievements of this team, working together with a performing Civil Works Contractor, made us undisputed dam building world champions, at every level.

Upstream view of Nam Theun 1 Dam spillway

Nam Theun 1 – New achievements for RCC dams

Paper by Kenneth A Ross and Gabriel A Escobar for the 9th International Symposium on Roller Compacted Concrete Dams and Cemented Material Dams