Hydro energy
Hydro energy is the electricity generated by harnessing the power of flowing or falling water. It is one of the oldest, most proven, and highly reliable sources of renewable energy in the world. Because India has a vast network of perennial rivers (especially in the Himalayas), hydro power plays a massive role in the country’s energy security.
How It Works:
The generation of hydroelectricity relies on a very simple conversion of energy:
- Storage: Water is stored at a great height in a large artificial lake or reservoir behind a massive dam. At this height, the water holds a huge amount of Potential Energy.
- The Flow: The water is allowed to flow downwards through massive, sloped pipes called penstocks. As it rushes down, the potential energy is converted into highly powerful Kinetic Energy.
- Power Generation: At the bottom of the penstock, the forceful water strikes the heavy blades of a turbine, making it spin rapidly. The turbine is connected to an electric generator. The spinning motion generates electricity, which is then sent to the power grid.
Key Components of a Hydro Power Plant
- Catchment Area: The geographical area from which rain and melting snow drain into the river and reservoir.
- Dam & Reservoir: A massive wall built across a river to hold back water, creating an artificial lake (reservoir) to store water and build up “head” (height).
- Penstock: A thick steel or concrete pipe that carries water from the reservoir down to the turbine under high pressure.
- Surge Tank: A small safety tank built along the penstock to absorb sudden pressure changes (water hammer) if the water valves are closed suddenly.
- Turbine: The mechanical wheel with blades. (Common types include Pelton, Francis, and Kaplan turbines, depending on water pressure).
- Generator: The machine that converts the mechanical rotation of the turbine into electrical current.
Classification of Hydro Power Projects in India
In India, hydroelectric power projects are primarily classified based on their installed power generation capacity. This classification helps the government effectively manage policies, subsidies, and environmental regulations.
Broadly, hydro power projects are divided into two main segments: Small Hydro and Large Hydro.
1. Small Hydro Power (SHP) Projects
In India, any hydro project with a station capacity of up to 25 Megawatts (MW) is officially categorized as a Small Hydro Power (SHP) project. These projects are highly beneficial because they usually do not require massive dams, thereby minimizing environmental damage and human displacement.
The SHP segment is further sub-divided into three specific categories:
- Micro Hydro: Projects with a capacity of up to 100 Kilowatts (KW).
- Mini Hydro: Projects with a capacity ranging from 101 KW to 2 MW.
- Small Hydro: Projects with a capacity ranging from 2 MW to 25 MW.
2. Large Hydro Projects (LHP):
Projects with a capacity above 25 MW.
- Important Note: Historically, LHPs were not counted under “Renewable Energy” due to their environmental impact. However, in March 2019, the Government of India officially declared all Large Hydro Projects as Renewable Energy Sources to help meet India’s global climate targets.
