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Fourth phase of Koyna hydroelectric project nears completion

The fourth phase of the Koyna hydroelectric power station, considered the lifeline of Maharashtra, will be completed by June 1998. In the fourth phase, four Indian-make generators will be set up to increase the power station's supply capacity by 250 megawatts.

Constructed at Pophali in the Konkan region, the Koyna station uses the water of a reservoir in the Sahyadri mountain range. Due to a limited supply of water in the reservoir, the same water will be used in the fourth phase by digging tunnels through the Sahyadri range.

The first phase of the project has four generators of 65 mw capacity each, the second phase four generators of 75 mw at Pophali, and in the third phase, four generators of 90 mw capacity of Kolkewadi which uses the same water for power production.

In the fourth phase, a tunnel was dug out from the Koyna dam in the upper reaches of Kolkewadi mountain and four generators of 250 mw capacity has been installed there. Numerous tunnels have been constructed across the Pophali-Koyna stretch of the Sahyadris, taking advantage of the hard rocks found in the region.

The fourth phase, which will cost Rs 12 billion, is to provide adequate supply of electricity for peak-hour demand. Technically, it is not possible for the Enron and Tata Power, which use fuel to generate electricity, to increase or decrease their supply as per demand. However, hydroelectro power stations can be used to meet peak load demand as they can produce power within a short span of four to five minutes using the flow of water failing from a high attitude.

It is for its ability to meet peak hour demand that the Koyna project fourth phase assumes importance. The cost of power from Koyna will also be cheaper. However, hydroelectric power projects have long gestation periods compared to fuel-based projects. Incidentally, the Tata stations plan to augment their capacity to 1920 mw after June 1998.

The most innovative aspect of this project includes the installation of a switchyard inside a tunnel. The earlier switchyards were located above the tunnels over a large surface area. This has helped save the land covering the project along with easing maintenance.

The project has not caused any displacement or pollution. The wheels of Koyna power project -- without any downsides -- will start turning when water at a speed of 65 metres per second, falling from an altitude of 650 metres, will turn the turbines of the four generators with a capacity of 250 mw.