Small Hydro Power (SHP) in India
A. Historical Background and Potential
India has a rich history of harnessing hydropower that spans over 120 years. The development of hydropower in India is marked by two historic milestones:
- First Project (1897): A small hydro project with a capacity of 130 kW was commissioned in the hills of Darjeeling, West Bengal.
- Second Project (1902): The Sivasamudram project (4500 kW) was established in the Mysore district of Karnataka, primarily to supply electricity to the Kolar Gold Mines.
Following these early successes, numerous small hydro projects were set up in hilly areas across the country. By the time of Independence (1947), India had a total installed power capacity of 1362 MW, out of which 508 MW came from hydropower projects (mostly small and medium-sized).
Today, the Ministry of New and Renewable Energy (MNRE) estimates that the total potential for Small Hydro Power in India is a massive 20 GW (20,000 MW).
B. Administrative Mandate
It is important to understand how the Government of India divides the responsibility for hydroelectricity:
- Ministry of Power: Responsible for Large Hydro Projects (capacity strictly greater than 25 MW).
- Ministry of New and Renewable Energy (MNRE): Responsible for Small Hydro Power (SHP) projects (capacity up to 25 MW).
C. Types of Small Hydro Projects
Small hydro projects are generally categorized into two types based on their geographical location and water flow mechanics:
1. Small Hydro Projects on Hill Streams (Run-of-the-River)
- Geography: Built on small mountain streams that have very steep slopes.
- Mechanics: These are usually Run-of-the-River schemes. They do not require a massive dam or a large stagnant reservoir. Instead, a small structure simply diverts a portion of the naturally flowing river water into a carefully designed conductor system.
- Components: The diverted water passes through a head regulator, travels down a power channel, goes through a desilting basin (to remove mud and rocks), and then drops rapidly through a pipe (penstock) into the powerhouse to turn the turbine. Finally, a “tail race” channel returns the water safely back to the original stream.
2. Small Hydro Projects on Canal Falls / Dam Toes
- Geography: Built on existing irrigation canals in the plains or right at the bottom (toe) of an existing dam.
- Mechanics: Irrigation canals carry massive amounts of water (high discharge) but at low heights (low heads). Wherever there is a natural drop or “fall” along the canal’s route, a small power plant can be constructed. A bypass channel is dug adjacent to the fall, the powerhouse is built on this bypass, and the water is then seamlessly rejoined to the main irrigation canal.
