Gangtok, Jan 08: The 510 MW Teesta Stage V Hydroelectric Project of Sikkim is going ahead of schedule, to be commissioned one year in advance on April 2006. The project envisages diversion of water of Teesta River through the twin diversion tunnel to make a concrete gravity dam near Dikchu village of South-North district of Sikkim. It will carry water through a 17 Km long Head Race Tunnel to the village Balutar in East Sikkim. Connecting the power house situated near Sherwani village, is an under ground power house having installed capacity of three 170 MW Turbo Generators. According to General Manager of Teesta Stage V of NHPC S K Mittal, the major contractor Gammon India Ltd and officers and staffs of NHPC, out of 17 Km, completed 10 Km long 9.5 dia Head Race Tunnel construction within 21 months on December 17, 2003, a record progress. He said the project will generate 2573 GWH in 90% dependable year on average.