Hydropower

What is Hydropower

Hydro is a Greek word, which means water. Hydro electricity is the conversion of the mechanical energy in flowing water into electricity. Hydro electricity is generated when the force of falling water from dams, rivers or waterfalls is used to turn turbines, which then drives generators that produce electricity. The energy produced is directed to a substation, where transformers "step up" the voltage before its transmission to the electricity grid.

Process of energy generation in Hydroelectric Power Plant

The first step in the generation of energy in a hydropower plant is the collection of run-off of seasonal rain and snow in lakes, streams and rivers, during the hydrological cycle. The run-off flows to dams downstream. The water falls through a dam, into the hydropower plant and turns a large wheel called a turbine. The turbine converts the energy of falling water into mechanical energy to drive the generator After this process has taken place electricity is transferred to the communities through transmission lines and the water is released back into the lakes, streams or rivers.

Classification of Hydro Projects based on Installed Capacity

Hydro power projects are generally categorized in two segments i.e. small and large hydro. In India, hydro projects up to 25 MW station capacities have been categorized as Small Hydro Power (SHP) projects.

• Micro: upto 100 KW
• Mini: 101KW to 2 MW
• Small: 2 MW to 25 MW
• Mega: Hydro projects with installed capacity >= 500 MW
• Thermal Projects with installed capacity >=1500 MW

While Ministry of Power, Government of India is responsible for large hydro projects, the mandate for the subject small hydro power (up to 25 MW) is given to Ministry of New and Renewable Energy.

Advantages of hydropower

• Hydropower is a renewable source of energy because it uses and not consumes the water for generation of electricity, and the hydropower leaves this vital resource available for other uses.
• It is a renewable source of energy with no consumables involved; there is very little recurring cost and hence no high long term expenditure. It is cheaper as compared to electricity generated from coal and gas fired plants. It also reduces the financial losses due to frequency fluctuations and it is more reliable as it is inflation free due to not usage of fossil fuel.
• Hydropower stations are preferred solution for meeting peak loads in grids due to its unique capabilities of quick starting and closing.
• The operational needs of hydro & thermal stations are complimentary and the balanced mix helps in optimal utilization of the capacity. Seasonal load curves of regional grids match with the pattern of hydro power generation. During summer/monsoon season when the generation at hydro power plants is high, the load factor of the system is high due to heavy agricultural load. During winter, the thermal stations operating at base load and hydro stations working as peak load stations will take care of weather beating loads.

Challenges related to hydropower

• The hydropower generation is highly capital-intensive mode of electricity generation.
• Due to the fact that hydropower projects are primarily located in hilly areas, where forest cover is comparatively better than plain areas, diversion of forest land is sometimes unavoidable.
• Submergence of land, thereby loss of flora and fauna and large scale displacement, due to the hydropower projects

Hydropower potential in India

The hydropower potential of India is around 1,45,000 MW and at 60% load factor, it can meet the demand of around 85, 000 MW. The estimated potential for power generation from Small hydropower projects is about 20,000 MW.

Source: Ministry of Power

Related Resources

1. List of Equipment Manufacturers of Small Hydro Power Turbine
2. Best Practices in Operation & Maintenance of Hydro Power stations