Nam Theun 1
Nam Theun 1 Hydropower Project (NT1 Project) is located on the Nam Kading River , approximately 33 km upstream of its confluence with Mekhong River , in central Lao PDR, Borikhamxai Province . The Nam Theun 1 dam and power station together is termed NT1 Project. NT1 Project consists of a 2-central arch-gravity dam constructed of roller compacted concrete (RCC) with a power house at the toe of the dam. The total install capacity is 523 MW which can generate energy of more than 2000 Gwh/year and will be evacuated through 500kv transmission line to collector substation (Nabong Sub- station) and then to EGAT system.
PROJECT STATUS in short
• MOU signed in May 2004.
• Project Development Agreement signed in November 2004.
• The technical feasibility study had been carried out in 2004 and completed in the end of that year. Environment Impact Assessment (EIA) was completed and approved by Science Technology and Environment Agency (STEA) of the Government of Lao PDR in 2005. The NT1 Social Action Plan and Environment Management Plan are expected to be completed in early 2007.
• Tariff MOU with EGAT signed on 18 th December 2006.
Main hydrological datd |
|
River system |
Nam Theun , Nam Kading |
Catchments area |
14,070 km 2 ,at the dam site |
Annual basin rainfall |
2,300 to 2,600 mm |
Annual reference evapo-transpiration |
1,400mm |
Mean river discharge (current situation) |
572 m 3 /s |
Mean annual discharge (current situation) |
18,000 x 10 6 m 3 |
Mean river discharge*) |
263 m 3 /s |
Mean annual discharge*) |
8,290 x10 6 m 3 |
*) value considers the effect of the upstream Nam Theun 2 HPP in operation, Theun Hinboun extension and NT3 |
|
Reservoir and water levels |
|
Type |
Storage |
Water levels: |
|
Full supply level (FSL) |
292 masl |
Minimum operation level (MOL) |
250 masl |
Crest level (HWL-design-flood) |
297 masl |
Maximum flood level (PMF) |
298.8 masl |
Reservoir |
|
Surface area at elevation 292masl |
80.7 km2 |
Surface area at elevation 300 masl |
112.3 km2 |
Volume at elevation 290 masl |
2,772 x 10 6 m 3 |
Volume at elevation 250 masl |
900 x10 6 m 3 |
Active storage (el.292 – 250 masl.) |
1,872 x10 6 m 3 |
Power generation |
|
Gross head |
|
Net head |
|
Maximum |
146.5m |
Rated |
134.0m |
Installed capacity |
523 MW |
Dam |
|
Type |
RCC arch- gravity dam with crest spillway |
Crest elevation |
297.00 masl |
River bed elevation |
125masl |
Deepest foundation elevation |
120masl |
Maximum height |
177m |
Crest length |
762m average (incl. spillway) |
Transmission Line |
|
Nominal voltage-export |
500kV |
Type |
Overhead double circuit line |
Length |
180 km to Lao-Thai Border via Nabong |