Shimla: Battle hardened Satluj Jal Vidyut Nigam Ltd (SJVNL) has drawn up plans to execute the country’s first twin tunnel hydro-power project as designs layouts emerge and the public sector generating company readies to invite civil works contract bids for the 775 MW Luhri project.
To be executed upstream of the NTPC’s Kol Dam project on Satluj river, the Himachal government awarded the Luhri project to SJVNL in October 2008 for which a detailed project report was under preparation since December 2004.
The geology in the area is weak and having a single head race tunnel for the Luhri project is not suitable, Avinash Kumar project head told My Himachal News. Instead the design team went about and have drawn up a twin tunnel plan, a first of its kind in India for harnessing the rivers energy, he added.
Having overcome many obstacles in commissioning the 1500 MW Natpha Jhakri project, the experienced pool of hydro engineers with SJVNL are confident of commissioning the Luhri project by 2017.
The project involves about 100 Kms of tunnelling thorough weak Himalayan geology to excavate two 38.14 kilometers long head race tunnels with a 9 meter diameter on the inside.
These tunnels would be 29 meters apart so that they are able to endure the pressure of water flowing through them without there be any danger of either one collapsing, said Kumar.
The Nigam has crafted out four civil works packages, consisting of Dam construction, two packages for head race tunnelling and the fourth one comprising of surge shaft and power house excavation.
Many construction firms are keen to bid for the contracts and have responded to the expression of interest (EOI) advertised, said the project head.
The run of the river project is to be dammed near Nirath village (about 100 Km from Shimla) and the power house is to come up at Marola village on Sunni-Sainj road.
Eight adits for excavation of head race tunnel have been proposed. Water would enter into a 5m dia 173.5m long pressure shaft which will feed 4 Francis turbines in a underground power house. The gross head of 221m would enable to generate 775MW of power.
The project is estimated to cost Rs. 4795 crore at December 2006 price level. The cost of per MW of installed capacity works out to Rs 6.19 crore which translates into Rs 2.53 per unit cost of power at levellised tariff. Starting out in 2010, the project is expected to be commissioned by 2017 and is expected to generate an annual revenue of Rs 800 crores.
For executing the project, a special purpose vehicle is to be constituted with 49 percent equity of Himachal government and 51 % central government share. Other than equity, the state would be entitled to 12 % free power and 1 percent of power cost would be spent for local area development, a SJVNL spokesman stated.
Other than operating the country’s largest hydropower project, SJVNL is in an advanced stage of exectuing the 412 MW Rampur project which will utilize the tail water of the 1500 MW Natpha Jhakri project. The Rampur project is scheduled to be commissioned by January 2012.