| Nam Ngiep 1 Main Reservoir | |
|---|---|
| Reservoir surface area | 66.9 square kilometres at normal level |
| Effective storage capacity | 1.2 billion cubic metres |
| Catchment area | 3,700 square kilometres |
| Average annual inflow | 4.7 billion cubic metres or 148.4 m3/s |
| Nam Ngiep 1 Main Dam | |
| Type | Roller-Compacted Concrete Gravity Dam |
| Crest height | 167 metres |
| Crest length | 530 metres |
| Spillway Discharge Capacity (4 x radial gates) | 5,210 cubic metres per second |
| Penstock Tunnel Length | 185 metres |
| Penstock Tunnel Diameter | 5.2 metres |
| Nam Ngiep 1 Main Powerhouse | |
| Turbine and generator | 2 Francis Units |
| Effective head | 130.9 metres |
| Rated output | 272 megawatts |
| Annual power generation | 1,546 gigawatt hours |
| Transmission line | 230 kilovolt line, 125 km to Nabong Substation |
| Nam Ngiep 1 Re-Regulation Reservoir | |
| Reservoir surface area | 1.27 square kilometres at normal level |
| Effective storage capacity | 4,600,000 cubic metres |
| Catchment area | 3,725 square kilometres |
| Nam Ngiep 1 Re-Regulation Dam | |
| Type | Concrete Gravity Dam |
| Crest height | 20 metres |
| Crest length | 90 metres |
| Discharge Capacity (fixed wheel gate) | 5,210 cubic metres per second |
| Nam Ngiep 1 Re-Regulation Powerhouse | |
| Turbine and generator | 1 Bulb Unit |
| Effective head | 12.7 metres |
| Rated output | 18 megawatts |
| Annual power generation | 105 gigawatt hours |
| Transmission line | 115 kilovolt line, 40 km to Pakxan Substation |