Nam Ngum 1 is one of Laos’s oldest and most strategically significant hydropower facilities, and its expansion has been central to EDL’s efforts to strengthen domestic energy security. In line with targets set under Laos’s 7th National Socio-Economic Plan, EDL and its generation subsidiary EDL-Gen identified the addition of a sixth generating unit at Nam Ngum 1 as a priority measure to reduce the growing gap between domestic power demand and supply, and to reduce over-reliance on independent power producers. The civil works scope for Unit No. 6 comprised construction of a new upstream intake structure at a rated head of 40 metres with roller gate, installation of a new 5.5-metre diameter penstock through the existing dam body, expansion of the powerhouse to accommodate a new Francis turbine-generator with a rated output of 40,900 kW and an umbrella-type generator rated at 50,000 kVA, ancillary plant installations, and expansion of the downstream tailrace. The project also included development of a new tool (software) in order to formulate the reservoir operation rule curves for efficient operation of hydropower dams across the Nam Ngum River Basin (NNRB) reflecting current condition of NNRB. The total construction works value was US$38.9 million.

LCG participated in joint venture with Nippon Koei Co. Ltd. and Electric Power Development Co. Ltd. (Japan) to deliver a full suite of consulting services spanning the project lifecycle. The team reviewed the existing feasibility study; conducted additional site investigations for detailed design including geotechnical investigations, topographic and hydrographic surveys, and concrete coring of the existing dam face; prepared detailed engineering designs for construction; developed tender documentation including construction drawings and technical specifications; assisted with the tender process and contract award; and provided full construction supervision through to completion — including management of on-site design variations arising from unforeseen ground conditions, assisted the project in development of reservoir operation rule curves in a part of hydrological analysis including data collection, rainfall analysis, estimation of long-term runoff (inflow data).

The successful addition of No. 6 turbine increased Nam Ngum 1’s installed generating capacity, contributing directly to EDL’s ability to meet growing domestic electricity demand with reliable, state-owned generation. By maximizing the productive capacity of an existing dam and reservoir rather than developing a new facility, the project represented a cost-effective and low-impact approach to closing Laos’s power supply gap. The development of river basin-wide reservoir operation rule curves further enhanced the long-term optimization of hydropower resources across the Nam Ngum catchment — a lasting contribution to national energy planning.