Lingza - Ministry of Power

1.0 INTRODUCTION
CHAPTER-I
EXECUTIVE SUMMARY
1
Preliminary Feasibility Report
Lingza HE Project (3 x 40 MW)
The Lingza Hydroelectric Project located in North Sikkim district of Sikkim envisages
utilization of the waters of the river Ringpi a tributary of river Rangyong for power
generation on a run of river type development, harnessing a head of about 746m.
The project with a proposed installation of 120MW (3 x 40MW) would afford an annual
energy generation of 477.51 GWh in a 90% dependable year. The tariff from the project
at present day cost would be Rs2.62 per KWh(levellised).
The diversion site is located at Latitude 27º36’ North, Longitude 88º27’20” East. The
dam site is approachable from Mangan-Lingza road by a footpath of 5km. The dam site is
at a distance of about 7km from Lingza and about 24km from Mangan, the head quarter
of North Sikkim district. The nearest railhead is at New Jalpaiguri and airport at
Bagdogra.
1.1 GENERAL PROJECT FEATURES
The Lingza HE Project envisages construction of :
• a 75 m high concrete Dam across river Ringpi to provide a live storage of
1.71mcum. with FRL at 1850m and MDDL at 1830m;
• two intakes and two desilting chambers of size 95m(L)x5m(W)x7.5m(H) to
remove silt particles of size 0.2mm and above;
• a 4km long , 3.3m diameter head race tunnel terminating in a surge shaft;
• a 40m high, 10m dia surge shaft;
• 900m long, 2m dia one pressure shaft;
• an underground power house having an installation of 3 Pelton turbine generating
units of 40 MW each operating under a net head of 736m; and