Tunneling-Hydro-Power

Dr D. G. Kadkade, Chief Adviser, Jaiprakash Associates Ltd, Noida

Introduction

Production of hydro power by use of water from rivers fed by snow melting upto the plains are tapped for production of hydro power by making diversion structures and a cascade of river water for using the head of water obtained from the difference in head between riverbed slope and water conductor system. By this system a static head upto 1000 metres has been used for production of hydro power. There are not many projects in power sector which have storages of water for producing hydro power throughout the year and round the clock. These involve big submergence of villages and forests. Therefore only few projects like Bhakra Nangal, Ram Ganga, Tehri, Rihand, Koyna, Srisailam, Nagarjuna and few more have been constructed as reservoir projects for generation of hydro power with substantial irrigation benefits.

The slope of the riverbed at higher altitudes is high and therefore even with low discharge substantial power can be generated. Based on this philosophy, the projects built by use of 'run of the river' are Baspa (300 MW), Vishnuprayag (400 MW) and Karcham Wangtoo (1000 MW) etc. After a hydro power project is commissioned, there is hardly any cost for maintenance and operation. From this point of view, they become economical.

Conservative approach that is now followed 'not to displace local population' and also controversial land acquisition have become problematic. Attempts are being made by the authorities in Central and State governments to make land acquisition with the consent of Panchayats and also doling out some benefits like school, hospital, temple and other facilities to woo the population affected by submergence. Government of India is trying to promote Land Acquisition Policy which is acceptable to the displaced population. For this purpose, the local population is allowed to put up their views in a public hearing before the project is okayed for clearance by the concerned authorities. The technology on underground excavation is developed in the world in a very big way. In order to acquaint the audience with present technology, details are presented hereunder.

NBM&CW June 2013