Water energy:

Water is a renewable source. Stored water has within itself potential energy this potential energy changes from one form of energy to another as kinetic energy which in turn changes into electric energy thus power is generated from water. This is how the energy that water has on its own is being utilized by the living beings.

Water is an essential component for every human being. In one form or other water plays a major role in everyone’s day to day activities.

How water energy works

The energy produced by the sun is the solar energy; this enhances the hydrologic cycle that provides water. The water or the moisture in the atmosphere reaches the earth surface as precipitation. From which a portion gets evaporated and a major portion percolates the soil or it forms as a surface runoff. The other source of water is the melting snow and rain. The water from them gets stored in the lakes, ponds, dams or ocean. Evaporation occurs continuously in these areas.

The water that reached deep inside the ground becomes surface water which can move up to the surface of the soil during drought periods and reaches the atmosphere as vapor. Then the cycle continues. So water is a renewable source of energy.


 

 

Water Power:

As stated above energy is not created new it is just the transformation of one form of energy to another. Let’s check how this energy transformation happens in case of producing electricity.

Water has potential energy on its own so for converting this into kinetic energy the water has to be in motion. Moving water carries kinetic energy and when this water flows through the blades of the turbine, it changes the kinetic energy into mechanical energy. This is further converted into electrical energy when the turbine rotates the generator rotor. From there electricity gets distributed.

Let’s now know how the water is used in power plants to generate electricity. In a hydroelectric power plant the following steps are involved in the process.

 

How water energy works : Intake

Intake: the dam opens its in way through which the water flows into the penstock (it is a gate or an intake structure that controls the flow of water) that directs the water towards the turbine. The pressure gets build as the water moves.

How water energy works : Rotation of the Turbine

Rotation of the Turbine: the turbine (it is a rotator mechanical device that is used in extraction of energy from moving fluids and converts it into useful work) that has vertical propeller blades set along the shaft that are linked to the generator. As the water flows through the blades the turbine rotates along its axis. This rotation converts the kinetic energy of the moving water into mechanical energy.

How water energy works : Electricity Generation

Electricity Generation: the turbines rotate and this correspondingly causes the magnets to rotate around the conductors which are in turn placed inside the generators producing the alternating current.

How water energy works : Conversion of energy

Conversion of energy:  the alternating current get s converted into voltage inside the generator with the help of the transformer. The voltage thus generated can be stored and used for further purpose.

How water energy works : Distribution of voltage

Distribution of voltage: the plants are attached to power lines that carry the varying voltage to the destinations for different use.

How water energy works : Outflow

Outflow: the water is then collected and made to reach the reservoirs again to continue the process.

How water energy works

Maximum Energy production depends on the volume of water and the height from which it flows. As the height increases the potential energy produced also increases resulting in increased power production. The distance between the turbine blades and the water surface is called as “Head” which is used as one of the measurement terms in determining the plant’s production capacity.

Based on the generating capacity of the plants they can be classified as follows

    • Small

    • Micro

    • Pico

How water energy works : Small Hydro Plant

The power plant which has the capacity to generate up to 10 MW is called as small hydro plant and this differs from country to country. From 2005 – 2008 this production grew. The capacity of small hydro plants may be up to 30 MW in china. Their storage capacity is also low and their impact to the environment is also low.


 

How water energy works : Micro hydro plant

The power plants that produce electricity up to 100 KW come under this category. This provides power to individual houses or to a very small community. This plays as an alternative to solar power in winter.

 

List of the largest hydroelectric power plants in the world.

SI.NO

DAM

COUNTRY

SOURCE

CAPACITY (KW)

ANNUAL Production (TW-HOUR)

1

Three Gorges Dam

People's Republic of China

Yangtze

22,500

98.5

2

Itaipu Dam

Brazil, Paraguay

Parana

14,000

98.3

3

Guri

Venezuela

Caroni

8,850

53.41

4

Tucurui

Brazil

Tocantins

8,370

41.43

5

Grand Coulee

United States

Columbia

6,809

20

6

Longtan Dam

People's Republic of China

Hongshui

6,426

18.7

7

Krasnoyarsk

Russia

Yenisei

6,000

20.4

8

Robert-Bourassa

Canada

La Grande

5,616

26.5

9

Churchill Falls

Canada

Churchill

5,428

35

10

Bratsk

Russia

Angara

4,500

22.6

 

Steam energy

 

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