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Hydroelectricity : A Process Which Is Made By Generators And Pushed By Movement Of Water...Find Out!

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Hydroelectricity

Electricity is the presence and flow of electric charge (electrons) in one direction. Using electricity we can transfer energy in ways that allow us to do common chores. Its best-known form is the flow of electrons through conductors such as copper wires.

The word "electricity" is sometimes used to mean "electrical energy". They are not the same thing: electricity is a transmission medium for electrical energy, like sea water is a transmission medium for wave energy. An item which allows electricity to move through it is called a conductor. Copper wires and other metal items are good conductors, allowing electricity to move through them and transmit electrical energy. Plastic is a bad conductor, also called an insulator, which does not allow much electricity to move through it so will stop transmission of electrical energy.

How is Electricity Produced?

Coal plays a vital role in electricity generation worldwide. Coal-fuelled power plants currently fuel 38% of global electricity and, in some countries, coal fuels a higher percentage of electricity. Steam coal, also known as thermal coal, is used in power stations to generate electricity. Coal is first milled to a fine powder, which increases the surface area and allows it to burn more quickly. In these pulverised coal combustion (PCC) systems, the powdered coal is blown into the combustion chamber of a boiler where it is burnt at high temperature. The hot gases and heat energy produced converts water ? in tubes lining the boiler ? into steam.

The high pressure steam is passed into a turbine containing thousands of propeller-like blades. The steam pushes these blades causing the turbine shaft to rotate at high speed. A generator is mounted at one end of the turbine shaft and consists of carefully wound wire coils. Electricity is generated when these are rapidly rotated in a strong magnetic field. After passing through the turbine, the steam is condensed and returned to the boiler to be heated once again.

The electricity generated is transformed into the higher voltages (up to 400,000 volts) used for economic, efficient transmission via power line grids. When it nears the point of consumption, such as our homes, the electricity is transformed down to the safer 100-250 voltage systems used in the domestic market.

Disadvantages of Coal-Fired Power Plants:

While coal has the potential to be a tremendous source of energy, it does have several drawbacks. The major disadvantage of coal is its negative impact on the environment. Coal-burning energy plants are a major source of air pollution and greenhouse gas emissions. In addition to carbon monoxide and heavy metals like mercury, the use of coal releases sulfur dioxide, a harmful substance linked to acid rain.

The extraction process can be detrimental to the environment as well as workers. Mining coal destroys habitats and has other negative effects on the environment like water pollution from the runoff. Coal mining also causes a large number of injuries and deaths each year. Fires in connected mine shafts are difficult to locate and extinguish. The combustion and the hollowed-out earth that destabilize the ground make some areas uninhabitable, which forces people to relocate.

There are also some other significant disadvantages of coal fired plants including Greenhouse Gas (GHG) Emissions, mining destruction, generation of millions of tons of waste, and emission of harmful substances.

1. Greenhouse gas emissions. It cannot be denied that coal leaves behind harmful byproducts upon combustion. These byproducts cause a lot of pollution and contribute to global warming. The increased carbon emissions brought about by coal fired plants has led to further global warming which results in climate changes.

2. Mining destruction. Mining of coal not only results in the destruction of habitat and scenery, but it also displaces humans as well. In many countries where coal is actively mined, many people are displaced in huge numbers due to the pitting of the earth brought about by underground mining. Places near coal mines are unsafe for human habitation as the land could cave in at anytime.

3. Generation of millions of tons of waste. Millions of tons of waste products which can no longer be reused are generated from coal fired plants. Aside from the fact that these waste products contribute to waste disposal problems, these also contain harmful substances.

4. Emission of harmful substances. Thermal plants like coal fired plants emit harmful substances to the environment. These include mercury, sulfur dioxide, carbon monoxide, mercury, selenium, and arsenic. These harmful substances not only cause acid rain but also are very harmful to humans as well.

We see a lot of disadvantages of electricity produced by coal as the gas which is released after coal is burned is very harmful. So now people starting producing electricity by water which is known as Hydropower or Hydroelectricity

Hydropower

Hydropower, or hydro energy , is a form of renewable energy that uses the water stored in dams, as well as flowing in rivers to create electricity in hydropower plants. The falling water rotates the blades of a turbine, which then spins a generator that converts the mechanical energy of the spinning turbine into electrical energy. Hydroelectric power is a significant component of electricity production worldwide.

Hydroelectric power for the Nation

Although most energy in the United States is produced by fossil-fuel and nuclear power plants, hydroelectricity is still important to the Nation. Nowadays, huge power generators are placed inside dams. Water flowing through the dams spin turbine blades (made from metal instead of leaves) which are connected to generators. Power is produced and is sent to homes and businesses.

World Distribution of Hydropower

Hydropower is the most important and widely-used renewable source of energy.

Hydropower represents about 17% (International Energy Agency) of total electricity production.

China is the largest producer of hydroelectricity, followed by Canada, Brazil, and the United States (Source: Energy Information Administration).

Approximately two-thirds of the economically feasible potential remains to be developed. Untapped hydro resources are still abundant in Latin America, Central Africa, India and China.

Producing electricity using hydroelectric power has some advantages over other power-producing methods. Let's do a quick comparison:

Advantages to Hydroelectric Power

? Fuel is not burned so there is minimal pollution

? Water to run the power plant is provided free by nature

? Hydropower plays a major role in reducing greenhouse gas emissions

? Relatively low operations and maintenance costs

? The technology is reliable and proven over time

? It's renewable - rainfall renews the water in the reservoir, so the fuel is almost always there

Hydropower and the Environment

Hydropower is non-polluting, but does have environmental impacts.

Hydropower does not pollute the water or the air. However, hydropower facilities can have large environmental impacts by changing the environment and affecting land use, homes, and natural habitats in the dam area.

Most hydroelectric power plants have a dam and a reservoir. These structures may obstruct fish migration and affect their populations. Operating a hydroelectric power plant may also change the water temperature and the river's flow. These changes may harm native plants and animals in the river and on land. Reservoirs may cover people's homes, important natural areas, agricultural land, and archaeological sites. So, building dams can require relocating people. Methane, a strong greenhouse gas, may also form in some reservoirs and be emitted to the atmosphere.

Typical Hydroelectric Power Plant

Hydroelectric energy is produced by the force of falling water. The capacity to produce this energy is dependent on both the available flow and the height from which it falls. Building up behind a high dam, water accumulates potential energy. This is transformed into mechanical energy when the water rushes down the sluice and strikes the rotary blades of turbine. The turbine's rotation spins electromagnets which generate current in stationary coils of wire. Finally, the current is put through a transformer where the voltage is increased for long distance transmission over power lines. Falling water produces hydroelectric power. The theory is to build a dam on a large river that has a large drop in elevation (there are not many hydroelectric plants in Kansas or Florida). The dam stores lots of water behind it in the reservoir. Near the bottom of the dam wall there is the water intake. Gravity causes it to fall through the penstock inside the dam. At the end of the penstock there is a turbine propeller, which is turned by the moving water. The shaft from the turbine goes up into the generator, which produces the power. Power lines are connected to the generator that carry electricity to your home and mine. The water continues past the propeller through the tailrace into the river past the dam.

Hydroelectric Power In India

India is the 7th largest producer of hydroelectric power in the world. As of 30 April 2017, India's installed utility-scale hydroelectric capacity was 44,594 MW, or 13.5% of its total utility power generation capacity. Additional smaller hydroelectric power units with a total capacity of 4,380 MW (1.3% of its total utility power generation capacity) have been installed. India's hydroelectric power potential is estimated at 148,700 MW at 60% load factor. In the fiscal year 2016-17, the total hydroelectric power generated in India was 122.31 TWh (excluding small hydro) with an average capacity factor of 33%.

The hydro-electric power plants at Darjeeling and Shivanasamudra were established in 1898 and 1902, respectively. They were among the first in Asia and India has been a dominant player in global hydroelectric power development. India also imports surplus hydroelectric power from Bhutan.

Small hydropower, defined to be generated at facilities with nameplate capacities up to 25 MW, comes under the ambit of the Ministry of New and Renewable energy (MNRE); whilst large hydro, defined as above 25 MW, comes under the ambit of Ministry of Power.

Pumped Storage Units

India has transformed from an electricity deficit state to an electricity surplus state. Peak load shortages can be met making use of pumped storage schemes which store surplus power to meet peak load demands. The pumped storage schemes also contribute secondary, seasonal power at no additional cost when rivers are flooded with excess water. India has already established nearly 4,800 MW pumped storage capacity with the installation of hydropower plants. Pumped storage units can also be used as pumping stations to supply river water for upland irrigation, industrial needs, and drinking water. In a tropical country like India, abundant water for agriculture is needed due to a very high annual evaporation rate. The amount of water necessary to meet this demand can be harnessed from India's rivers via pumped storage units. Food security in India is improved with water security which in turn is possible from the energy security to supply the power needed for the pumped storage schemes.

More and more solar power generation is becoming available at a cheaper cost and it has advantages in terms of environmental impact. Solar power can meet daytime and night time energy demands with the help of pumped storage units.

Many of the existing hydro power stations on the west-flowing rivers located in the Western Ghats of Kerala and Karnataka are to be expanded to include pumped storage units in an effort to solve the water deficit of east-flowing rivers like the Kaveri, Krishna, etc.



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