Xe Pian Xe Namnoy Hydroelectric Power Project

Xe-Pian Xe-Namnoy Power Company's (PNPC) 410MW Xe Pian Xe Namnoy hydroelectric power project is located in the southern region of Lao People's Democratic Republic (Lao PDR).

Project Type

Hydroelectric power project



Installed Capacity


Start of Construction

February 2013


Xe-Pian Xe-Namnoy Power Company’s (PNPC) 410MW Xe Pian Xe Namnoy hydroelectric power project is located in the southern region of Lao People’s Democratic Republic (Lao PDR). When completed, it was estimated that it would have an annual energy generation of approximately 1,860GWh.

However, late on 22 July 2018, workers discovered that one of the three auxiliary dams within the colossal project was damaged and began evacuating people living in nearby villages. The following day, the dam collapsed sending a wall of water into six surrounding villages.

By 25 July, 20 people have been killed by the water, a further 100 are missing and nearly 7,000 people have lost their homes. An estimated 175 billion cubic feet of water was released, from a tributary of the Mekong River.

PNPC is a joint-venture formed in March 2012 by SK Engineering and Construction (SK E&C), Korea Western Power (KOWEPO), Ratchaburi Electricity Generating Holding (RATCH), and Lao Holding State Enterprise (LHSE). SK E&C holds 24% stake in PNPC, LHSE 26%, and RATCH and KOWEPO equally own the remaining share in the project.

The project, which was estimated to cost $1.02bn, was the first build-operate-transfer (BOT) project to be undertaken by the Korean companies in Laos. The leaders of the small nation, hope that hydroelectric power will help the nation develop and grow.

The feasibility study for the hydroelectric project was completed in November 2008. Construction of the project began in February 2013 and commercial operations were expected to begin in late 2018. At the time of collapse, the dam was 90% complete.

Xe Pian Xe Namnoy hydroelectric power plant details

The Xe Pian Xe Namnoy power project is located on the Bolaven plateau, approximately 550km southeast of the capital Vientiane city of Laos. The project was being developed on a 238ha land leased for a period of 32 years.

The project includes the construction of three dams: Houay Makchan Dam, Xe Pian Dam, and Xe-Namnoy Dam along the Mekong River. In addition, the project includes three auxiliary, or saddle dams, such as the Saddle Dam D which failed. It includes a large storage reservoir on the Xe Namnoy River, underground tunnels, shaft waterways, and an open-air powerhouse featuring four generator units (three Francis turbines and one Pelton turbine).

The Xe Namnoy reservoir was designed to be 73m-high and 1,600m-long, and have the capacity to store approximately 1,043 million cubic meters (MCM) of water. Approximately 1,000MCM of water will be collected from Houay Makchan and Xe Pian catchments and stored at the Xe Namnoy reservoir.

The power house, which was located at the base of the valley, would generate power using gravitational force of fall and flowing water from a height of 630m. The water would then of flowed through the tailrace channel and have beendischarged into the Xe Kong River.

PNPC intended to transit the power generated at the Xe Namnoy power house to the Electricity Generating Authority of Thailand (EGAT) through a 230/500kV transmission line and to Electricité du Laos (EdL) through an 115kV transmission line.

Out of the 410MW produced, 370MW was destined for EGAT under a 27-year power purchase agreement signed in November 2012 and the remaining 40MW to EdL.

The Xe Pian Xe Namnoy project is the first major power investment in Laos by South Korean sponsors SKE&C and KOWEPO.

The project achieved financial closure in February 2014 and is financed through 70% debt and 30% equity. Debt financing of approximately $737.5m is provided by a syndicate of Thai financial institutions including Bank of Ayudhya, The Export- Import Bank of Thailand, Krung Thai Bank, and Thanachart Bank.

Contractors involved

SK E&C was awarded the engineering, procurement and construction contract for the construction of the project, while KOWEPCO was awarded the operations and maintenance contract for a period of 27 years. Ratch is responsible for the construction supervision of the project.

Tractebel Engineering was engaged as owner’s engineer for the hydropower plant construction. KTB Advisory, Australia and New Zealand Banking Group, and the Export-Import Bank of Korea are the financial advisors for the project.

SK E&C awarded a civil works sub-contract to Right Tunnelling for the construction of high and low-pressure tunnels.

TEAM GROUP prepared the basic design and tender documents, along with the environmental impact assessment for the project. ATT Consultants were engaged for designing the transmission system model, which will enable the transfer of power to Thailand.

AF Consult was engaged to conduct pre-feasibility and feasibility studies, engineering for basic design and tender documents, environmental and social management aspects, and to provide support services for finalising the concession and power purchase agreements.


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