A controlled explosion will take place at the Koyna reservoir on Wednesday in a procedure known as lake tapping to ensure that power-generating turbines operate uninterrupted at a higher speed. The event will help the power-deficient state continue its efforts to plug a demand-supply gap in peak hours by at least 1,000 MW.
For lake tapping, an intake tunnel is dug under the water source. Then, a controlled blast is used to throw open a rock plug at the mouth of the tunnel and create a surge of water to operate the turbines.
Wednesday's tapping will help the Stage IV of the Koyna to operate its turbines at a higher rate even when the reservoir's water level goes down. DN Modak, chief engineer (civil-hydro projects), said that lake tapping would allow uninterrupted operations even if the water level in the dam falls below 630 metres. It will also ensure that three other dams down the river get ample water.
The Koyna dam is situated in the Sahyadri mountain range, about 300 km south-east of Mumbai. Koyna hydro-electricity (hydel) power project started operating in stages between 1962 and 1967.
Unlike thermal units, which take 12-24 hours to attain full capacity, hydel projects start generation at maximum level within minutes. That way, Koyna, with its 1,920 MW capacity, has bailed out the state over the past eight summers.
Chief minister Prithviraj Chavan, his deputy Ajit Pawar, who heads energy department, and water resources minister Sunil Tatkare will trigger the blast on April 25.
The only other time lake tapping was performed at the Koyna was thirteen years ago, in March 1999, when the state government successfully used the procedure — a first-of-its-kind in Asia — for Stage IV.