Nam Theun 2 Hydropower Project

Canadian Consulting Engineering Award

Design for robust, functional and environmentally responsible operation

Nam Theun 2 (NT2) is a 1,074 MW hydroelectric dam on the Nam Theun River in Laos. It is the most important project in a long-term collaborative effort between Laos and Thailand to develop up to 3,000 MW of hydropower energy in Laos, mainly for export to Thailand. Électricité de France, the lead proponent for NT2, envisioned the project would provide “inexpensive electricity to drive human development”. KCB undertook the NT2 design in accordance with this vision and adhered to the principle of providing robust, functional facilities capable of safe, environmentally responsible operation.

We are proud of the technical design that was accomplished on this challenging project and of the direct benefits to the people of Laos and Thailand.

Challenges

  • High capacity diversion system needed due to river’s large flood events
  • Balancing construction logistics, stakeholder concerns and environmental issues
  • Design water passage for large combination of head and flow
  • Compliance with local architecture/aesthetic design elements
  • Safety challenges related to unexploded land mines

Solutions

  • Innovative and economic flood handling method designed. We recommended using small diversion tunnel and roller-compacted concrete (RCC) construction for main dam and cofferdams
  • Largest pressure-diameter bifurcations ever designed and constructed
  • Skilled Lao stone masons employed to carefully cut, sculpt and hand-place riprap in canal and drainage works
  • Worked closely with contractor to understand construction material availability issues and economics of sourcing and re-using construction materials
  • Aggregate materials sourced and crushed at local quarry, rather than hauling materials from long distances or river deposits
  • Excavated materials from project site re-used for roads and flood protection

Successes

  • RCC construction allowed overtopping during wet season while keeping structures intact; only de-watering and clean-up needed before resuming construction
  • Bifurcation design established precedent in hydro industry for use of selected steel types and thicknesses
  • Over 8,000 workers at peak of construction; 80% were Lao. Project construction generated indirect jobs for small community businesses
  • Inclusion of Lao culture/aesthetics in architectural design of powerhouse
  • Poverty Reduction Fund implemented by Laos and World Bank with direct funding from NT2 energy revenues
  • New housing and community buildings with electricity provided to 6500 people in project area
  • Local population now has access to inexpensive electricity and have a resource for export
  • The project’s benefits spread beyond Laos to Thailand where the power exported from NT2 can power about 3 million Thai homes