Koyna Hydroelectric Project

The Koyna Hydroelectric Project is the largest completed hydroelectric power plant in India. It is a complex project with four dams including the largest dam on the Koyna River, Maharashtra hence the name Koyna Hydroelectric Project. The project site is in Satara district near Patan. The village Helwak near the dam was later known as Koynanagar.

The total capacity of the project is 1,960 MW. The project consists of four stages of power generation. All the generators are located in underground powerhouses excavated deep inside the mountains of the Western Ghats. A dam foot powerhouse also contributes to the electricity generation. Due to the project's electricity generating potential the Koyna River is considered as the life line of Maharashtra.

The project takes advantage of the height of Western Ghats. Thus a very large hydraulic head is available over a very short distance.

In the early 20th century, there was a survey of the Koyna River as a potential hydro-electric source. After the First World War, a hydro-electric project on the Koyna river was investigated by the Tata Group. The 1928 financial crisis caused the project to be shelved. After the independence of India, it was taken over by the Government of Maharashtra. In 1951 Koyna Dam division started to look into the project. The project was approved in 1953 and work commenced in early 1954.

The project is composed of four dams with the major contributors being the Koyna Dam and Kolkewadi Dam. The water from Shivasagar reservoir was formed by the Koyna Dam and is used in the 1st, 2nd and 4th stages. This water is drawn from head race tunnels situated below the reservoir. Then it travels through vertical pressure shafts to the underground powerhouses. The discharged water from these stages is collected and stored in Kolkewadi Dam situated near village of Alore. The water is drawn from the of Kolkewadi Dam to an underground power station in the 3rd stage and then discharged to the Arabian Sea.

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