[Physics Class Notes] on Hydroelectricity and Hydropower Plant Pdf for Exam

Conventional sources of energy are the energy that is naturally available in nature. They are present in a minimal amount in the world, and will one day perish if it is not sustainably used. Natural gas, coal, oil, thermal power plants, hydroelectricity, and hydropower plants are some of the examples of conventional sources of energy. Among these sources, hydroelectricity is considered to be clean and an efficient source of energy for long term use.

 

The most significant disadvantage of conventional sources of energy is that they tend to pollute the environment. They are also very limited and finite in terms of quantity available for extraction. The only exception is hydroelectricity. India has a high potential to produce electricity with hydropower plants. Only 15% of the total open source is being used right now. Therefore, you need to get a proper grasp on what is hydroelectricity and on what is hydropower plant.

 

Hydroelectricity

Let’s start by answering the question of what is hydroelectricity. When electrical current is generated from the kinetic energy of flowing water, we call it hydroelectricity. It could be a water turbine driven electric generator in a dam, a generator driven by a water wheel in a water stream, or even an air-driven electric generator in which air is compressed to drive the generator by the action of ocean waves.

 

Advantages of Hydroelectricity:

• It is a clean and non-polluting source of energy.

• No fuel is required. Water is the source of energy, and it does not consume water.

• Dams are constructed near rivers. As the water level rises, the kinetic energy of water gets changed to potential energy.

 

Disadvantages of Hydroelectricity:

 

Uses of Hydroelectricity:

 

Hydropower Plant

Let’s try to understand what is hydropower plant. When water is at a height, it has potential energy stored in it. When this water flows down, its potential energy is first converted to kinetic energy and then to mechanical energy with the help of turbines. With the use of a generator, the mechanical energy is transformed into electrical energy. Hydropower is essential only next to thermal power. Hydropower plants meet nearly 20% of the total power of the world.

 

Advantages of Hydropower Plants:

• Rainwater is stored in the dam. Thus, it is considered to be a renewable source of energy.

• The construction of dams helps in providing irrigation of the local farmers; it also helps in controlling floods.

• This method of electricity generation does not produce any pollution.

• Their operational cost is very low.

 

The Disadvantage of Hydropower Plants:

• Hydropower plants require high capital with a low rate of return.

• Dams can only be built at specific locations.

• A Large area of agriculture is submerged underwater.

 

Uses of Hydropower Plants:

• Since the generation of electricity in hydropower plants is very quick, they can provide essential back-up power during major electricity outages.

• Hydropower is used to control flood, help in irrigation, and water supply.

• Hydropower plays a major role in reducing greenhouse gas emissions.

 

Working Principle of Hydropower Plant

Now that you have a thorough understanding of what is hydroelectricity, and on what is hydropower plant, we will soon see how is hydroelectricity produced in the plants. We use the gravitational force of the water to produce electricity. 

 

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The first thing that we need is a high-rise dam to stop the flow of water and accumulate it in one place. When all the water is gathered, a lot of potential energy is stored in the water. Next, the sluice gates are opened up, and the water is made to flow with high pressure. When water flows, the potential energy gets converted into kinetic energy. When the running water hits the blades of a turbine, the kinetic energy of the water is converted into mechanical energy. This turbine is in turn connected to a generator. As the turbine rotates rapidly, the generator generates electricity in the powerhouse. The used water will flow out into the river, and the water level in the dam decreases. This level will increase once again with the help of natural rainwater. Therefore, it is a natural resource that will never get exhausted.

 

World Distribution of Hydropower

The most crucial and widely used renewable source of energy is hydroelectricity which is produced in hydropower plants. Hydropower plants meet only 20% of the total power of the world. When it comes to the production of hydroelectricity, China is the largest producer, followed by the United States, Brazil, and Canada. Around 66% of the economically feasible hydropower is yet to be tapped. Untapped resources are still present in Central Africa, China, India, and Latin America.

• Hydropower remains the dominant electricity source across North and Central America.

• South America was the second-fastest-growing region, adding 4,855 MW in installed hydropower capacity in 2018.

• Hydropower is increasingly recognised in Europe for its flexible services to maintain secure, affordable and sustainable energy supply

• East Asia and the Pacific again saw the highest annual increase in hydropower installed capacity in 2018.