energy from water
TRANSCRIPT
Energy from waterHydropower
By:
Abnet mengesha
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Outline
Objectives of the project
Introduction
What is energy?
Types of energy
What is renewable energies?
Water energy
Does water contain energy?
Can energy be generated through water?
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Outline(con’t)
What is hydroelectric power?
How is energy generated in a hydroelectric power plant?
How A Hydropower plant works?
Advantages of hydroelectric power
Disadvantages of hydroelectric power
Summary
Discussion and conclusion
References
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Objectives of the project
• The main objectives of this project are:
To know as water has energy.
To differentiate d/t types of energies.
To know the d/ce b/n renewable and nonrenewable energy
To know how energy is produced from water.
To know the advantages and disadvantages of hydropower.
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Introduction
• Present day water and energy systems are interdependent. Water is used in all phases of energy production and electricity generation. Energy is required to extract, convey, and deliver water of appropriate quality for diverse human uses, and then again to treat wastewaters prior to their return to the environment.
•We use many different sources to meet our energy needs. All sources have advantages and disadvantages. Some are cheap; others are expensive. Some contribute to global warming; others are pollution-free. Some are limited in their supplies; others are abundant. Some are always available; others are only available some of the time.
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Introduction (con’t)
• Renewable energy sources include biomass, geothermal energy, hydropower, solar energy, and wind energy. They are called renewable because they are replenished in a short time. Day after day, the sun shines, the wind blows, the rivers flow, and plants grow.
• We can harness this renewable energy to do work for us. We use renewable energy sources mainly to make electricity. Here our project focus is on hydroelectric power or energy from water.
• Hydroelectric power is electricity generated by hydropower. Hydropower is harnessed through the gravitational force of falling or flowing water. On a worldwide standpoint, it is the most widely used form of renewable energy. Hydropower has been used for centuries by humans. The electricity is typically created when the water is passed over large mechanical turbines, the water pressure forces the turbines to turn, the mechanical energy created is then converted into electricity.
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What is energy?
• Energy is the capacity to do work and transfer heat. Work is performed when an object or substance is moved over some distance. Energy is needed to carry out processes, such as boiling water or burning candles. Energy is also the heat that flows from a hot object or substance to a cold one, when they come in contact. A clear example of this is the fact that water heats up when you put in a water boiler device.
• Energy has many forms, such as light, heat, electricity, chemical energy (stored in chemical bonds) and mechanical energy (moving matter, such as flowing water).
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Types of energy
• All energy forms are divided up between two main kinds of energy. The first main kind of energy is kinetic energy, the energy of motion and action. Heat is a total of kinetic energy of atoms, ions or molecules. When these chemical compounds are in motion due to kinetic energy they will warm up.
• The second main kind of energy is potential energy, energy that is stored and potentially available for use. Before potential energy can be used it is transferred into kinetic energy. An example of an object containing merely potential energy is a dice that you hold in your hand. When you throw the dice the potential energy is transferred into kinetic energy and this will cause the movement.
• Energy sources are also classified into two groups—renewable and nonrenewable.
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What is renewable energies?
• Renewable energy sources include biomass, geothermal energy, hydropower, solar energy, and wind energy. They are called renewable because they are replenished in a short time. Day after day, the sun shines, the wind blows, the rivers flow, and plants grow.
• We can harness this renewable energy to do work for us. We use renewable energy sources mainly to make electricity. Here our project focus is on hydroelectric power or energy from water.
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Water energy
• Water, like many substances, contains two kinds of energy. The first kind of energy is called kinetic energy. This is energy that is used during the execution of processes, such as movement. Because of kinetic energy water can flow and waves can exist.
• But water can also contain potential energy. This is energy that is stored in the water. Stored, but not used. This energy can become useful when water starts to flow. It will be transferred to kinetic energy and this will cause movement.
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Can energy be generated through water?
• When water flows or falls, energy can be generated. The generation of energy through water is usually carried out in large water power plants, with a number of process steps and the use of several devices, such as turbines and generators. The energy in water can be used to produce electricity.
• The energy from moving water can be used to create electricity in several different ways. For example: A hydroelectric dam captures energy from the movement of a river. Dam operators control the flow of water and the amount of electricity produced.
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What is hydroelectric power?
• Hydroelectric power is electricity that is supplied by generating energy from falling or streaming water. Hydroelectric power is a so-called renewable energy source. This means that the source, which provides the energy, can be renewed. This is because, unlike non-renewable energy sources such as crude oil, we will not run out of water fully. It can be renewed after we have used it for energy generation.
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Hydropower plant
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How is energy generated in a hydroelectric power plant?
• A hydroelectric power plant consists of a high dam that is built across a large river to create a reservoir, and a station where the process of energy conversion to electricity takes place.
• 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.
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Con’t
• The turbine converts the energy of falling water into mechanical energy to drive the generator. It turns a shaft, which rotates a number of magnets in the generator. When the magnets pass copper coils a magnetic field is created, which aids the production of electricity. Step-up transformers will than increase the voltage of the electricity, to levels needed for the journey to communities. 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. This is entirely not harmful, because no pollutants are added to the water while it flows through the hydropower plant.
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Hydropower generation process
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Hydroelectric dam in cross section
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How A Hydropower plant works?
• Dam: controls the flow of water and creates a reservoir of water above for energy use when needed
• Penstock: pipe channeling water from the dam to the turbines
• Turbines: large blades attached to a cylinder that move when the water pushes against it
• Generator: parts connected to the turbines that create the electricity by moving large magnets
• Inductor: changes the form of electricity to one that can be used
• Transmission Lines: transport energy to places that need it
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Advantages
•Once a dam is constructed, electricity can be produced at a constant rate.
•If electricity is not needed, the sluice gates can be shut, stopping electricity generation. The water can be saved for use another time when electricity demand is high.
• Dams are designed to last many decades and so can contribute to the generation of electricity for many years / decades.
•The lake that forms behind the dam can be used for water sports and leisure / pleasure activities. Often large dams become tourist attractions in their own right.
•The lake's water can be used for irrigation purposes.
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Con’t
• The buildup of water in the lake means that energy can be stored until needed, when the water is released to produce electricity.
• When in use, electricity produced by dam systems do not produce greenhouse gases. They do not pollute the atmosphere.
• Hydropower has a moderate to high amount of useful energy
• Fairly low operating and maintenance costs.
• In general, renewable, green, reliable, flexible and safe.
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Disadvantages
• Dams are extremely expensive to build and must be built to a very high standard.
• The high cost of dam construction means that they must operate for many decades to become profitable.
• The flooding of large areas of land means that the natural environment is destroyed.
• People living in villages and towns that are in the valley to be flooded, must move out. This means that they lose their farms and businesses. In some countries, people are forcibly removed so that hydro-power schemes can go ahead.
• The building of large dams can cause serious geological damage.
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Cont’
• Dams built blocking the progress of a river in one country usually means that the water supply from the same river in the following country is out of their control. This can lead to serious problems between neighboring countries.
• A hydroelectric power plant takes up a lot of space and this may cause animal habitats to go lost.
• Large-scale projects can threaten recreational activities and disrupt the flows of rivers.
• Due to the presence of dams and reservoirs, fish may not be able to swim to sea and aquatic life may decrease in the area of the hydroelectric power plant.
• In general, environmental consequence, expensive, droughts and limited reservoirs.
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Summary
• Energy and water are two interdependent things.
• We needs many sources of energy to meet our day to day activities. And every energy source has its own advantages and disadvantages.
• Energy is the ability to do work and transfer heat.
• Generally, energy is classified in two main classes, as kinetic and potential energy. Kinetic energy related with motion of body and the potential energy related to the position and shape of the source.
• Energy also divided into two as renewable and nonrenewable. Renewable energy that has naturally replenished sources and nonrenewable energy has the source that is not naturally replenished.
• Hydro energy is a form of renewable energy that uses water stored in dams and flowing in rivers to create electricity.
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Summary
• Hydropower is one of renewable energy that produced from water, by converting the potential energy of water into electrical energy. It is electricity
• Water as other substances contain two types of water, kinetics and potential energies.
• As the turbine spins, it turns a metal shaft connected an electric generator, which is basically a motor that produces electricity. In the case of a hydroelectric dam, it's flowing water that's used as the power source to turn the turbine.
• Hydroelectric power is electricity that is supplied by generating energy from falling or streaming water.
• In general, the hydropower energy, has advantages like, renewable, green, reliable, flexible and safe.
• In general, has disadvantages like, environmental consequence, expensive, droughts and limited reservoirs.
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Discussion and conclusion
• We use many different sources to meet our energy needs. All sources have advantages and disadvantages. Some are cheap; others are expensive. Some contribute to global warming; others are pollution-free. Some are limited in their supplies; others are abundant. Some are always available; others are only available some of the time.
• As seen above, water is the renewable source of energy, implies that we can produce large amount of energy that needed for our all activities. This is because the water energy is renewable (not limited), green (has not emit greenhouse gases), reliable, flexible and safe. And water that is stored in the dam used for other many purposes, like irrigation, fishing, and recreational activities. Even if it has lots of advantages it also has disadvantages, like high cost of dam construction, take larger area, and displace habitats from their original placement.
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References:
• http://www.worldwaterweek.org/wpcontent/uploads/2014/08/2014_WWW_Report_web-2.pdf
• http://www.lenntech.com/water-energy-faq.htm
• http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/eng4431
• https://www.google.com/search?q=energy+from+wate
• http://www.slideshare.net/srgirlsdk/hydro-power-ppt
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Thank you
The end
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