Tehri Dam . Operator . THDC Limited, uttrakhand

Koyna Hydroelectric project .
operator : MAHAGENCO , Maharashtra
state power generation Co Ltd

The way hydel power score over thermal :

Hydro electric & Thermal power generation are the two prominent conventional generation modes, widely used for the generation of electric power. Comparison between the two is as below:

1. Environmental

i. Hydro power Generation is comparatively environmental friendly. The emission from the immediate process of power generation is nil, whereas Thermal power units are notorious for their emissions. Major pollutants from thermal generation will be suspended particulate matter (solid Fuel), Sulphur Oxides (all fuels prominently for Solid & liquid), Nitrogen Oxides (for all combustion process), Ash generation in case of Solid Fuels, Heavy metals etc.

ii. Since the power generation is utilising only water at ambient temperature, thermal effects to environment is nil.

iii. Disposal of waste is one of the most unresolved environmental issues. In India, most of the power plants operate with High ash coal in the range of 30-40%.

iv. Hydro power is considered as clean energy whereas thermal energy is dirty, in the point of view of environment.

v. Interruption and regulation in the river flow can affect the environmental conditions in the downstream.

2. Process Complexity

i. Process of Hydro Power Generation is simple. It has only very less auxiliary equipment in the process cycle,, as compared to thermal power plants.

ii. Power required to generate power (Auxiliary power Consumption) is marginal, around 0.5 % of generated power, whereas high capacity power plants consume around 7-8 % of Power.

iii. Power generation increasing / decreasing rates (ramp rates) are instantaneous for Hydropower plant. Thermal power plants takes much more time, especially Coal power plants take around day, when started from cold condition. (Initial start-up or start up after the temperature of critical equipment has reduced substantially.

3. Safety

i. Chances of accidents from the process are very low. As the process is simple with few number of equipment (compared to thermal & Nuclear Generation) are in the process cycle. A thermal plant uses steam / combustion gases at very high temperature & pressure. Most of the high capacity thermal power plants uses Steam from 530-565 Degree Celsius!

ii. Since no combustive material is used for the process, the accidents due to uncontrolled combustion are eliminated. (Equipment fire during operation and electrical fire is common for all power generation modes.)

4. Economy :

i. Construction cost of Hydro Power plant is high as compared to thermal power plant. Since the operating costs are marginal, Generation cost of Power in Hydro power plant ends up in less unit cost, as compared to thermal power generation.

ii. Availability of water is nature dependent and source is considered as renewable. The availability & price of thermal fuels like Coal, Liquid Fuels , natural gas etc are market dependant

5. Limitations

i. Unit Generation capacity becomes limitation, in relation to Storage capacity of dams. Unit sizes of 700-770 MW are available with huge reservoirs like Three Gorges Dam in Yangtze River, Itapúa Dam in Brazil –Paraguay Border etc. Normal capacity of units is in the range of 100-250 MW.

ii. Dam Require huge water storage area. This will result in the destruction of Avast Eco system. Green House Gas generation from the decay is argued to be higher than the Carbon emission from the coal based power plants.

iii. Storage area of Hydro Dams is very large. The displacement of communities due to the construction of dams are huge

Different hydel-power projects in India:

1. Bhakra Nangal Dam:
- Located on the Satluj River in Himachal Pradesh.
- One of the largest hydel-power projects in India.
- Consists of two dams: Bhakra Dam and Nangal Dam.
- Generates about 1,325 MW of electricity.

2. Tehri Dam:
- Located on the Bhagirathi River in Uttarakhand.
- One of the tallest dams in the world.
- Generates about 1,000 MW of electricity.
- Also serves as a multipurpose project for irrigation, drinking water supply, and flood control.

3. Sardar Sarovar Dam:
- Located on the Narmada River in Gujarat.
- One of the largest dams in India.
- Generates about 1,450 MW of electricity.
- Provides water for irrigation and drinking purposes.

4. Koyna Dam:
- Located on the Koyna River in Maharashtra.
- Generates about 1,920 MW of electricity.
- Known for its underground power station.

5. Nathpa Jhakri Dam:
- Located on the Satluj River in Himachal Pradesh.
- One of the largest underground power stations in India.
- Generates about 1,500 MW of electricity.

Hydel power vs. thermal power:

1. Renewable and Environment-Friendly:
- Hydel power is generated using flowing water, which is a renewable source of energy.
- It does not emit greenhouse gases or pollutants like thermal power, making it environmentally friendly.

2. Cost-effective and Reliable:
- Hydel power has a lower cost of production compared to thermal power.
- Once the hydel-power projects are built, the operational costs are relatively low.
- Hydel power plants also have a longer lifespan compared to thermal power plants.

3. Water Management and Irrigation:
- Hydel power projects often involve the construction of dams, which can help in water management and irrigation.
- These dams can store water during the monsoon season and release it during dry periods, ensuring a continuous water supply for agriculture.

4. Reduced Dependence on Fossil Fuels:
- Hydel power reduces the dependence on fossil fuels like coal and oil, which are limited and contribute to air pollution and climate change.
- It helps in diversifying the energy mix and reducing the carbon footprint of the country.

In conclusion, hydel-power projects in India have several advantages over thermal power. They are renewable, cost-effective, reliable, and environmentally friendly. Additionally, hydel power provides benefits like water management, irrigation, and reduced dependence on fossil fuels. These factors make hydel power a sustainable and desirable source of energy for India's growing energy needs.