Basic Concepts Of Electrical Power Generation

The fundamental principles of electricity generation were discovered during the 1820s and early 1830s by the British scientist Michael Faraday. His basic method is still used today. That is electricity is generated by the movement of a loop of wire, or disc of copper between the poles of a magnet. For electric utilities, it is the first process in the delivery of electricity to consumers.

Power generation consists of technologies used for electricity production from various energy sources.
These energy sources include renewable energy and nonrenewable energy. Renewable energy are those energy flows that occur naturally and repeatedly in the environment can be exploit for human benefit including power generation. The ultimate sources of most of these energies are the sun, gravity, and the earth’s rotation. Non renewable energy sources are those which are obtained from static stores of energy that remain bound unless released by human interaction. These include nuclear fuels and fossil fuels, coal, oil and natural gas etc.

Electricity

Electricity is considered to be a secondary source of energy, as it is not produced as readymade. Its generation needs some primary source of energy includes wind, sunlight, coal, natural gas, nuclear fission reactions, and hydropower. Electricity can be defined as a form of energy that is produced as a result of the flow of electrons from positive and negative points within a conductor. Electricity is both a basic part of nature and one of the most widely used forms of energy.

Basic Methods To Generate Electricity

Here are some fundamental ways to produce electricity.

Generation Of Electricity Through Rubbing

When two different materials are rubbed together, there is a transfer of electrons from one material to the other material. When one object is rubbed against another, static electricity can be created. This is because the rubbing creates a negative charge that is carried by electrons. The electrons can build up to produce static electricity. Static electricity is generated by friction between two insulating materials. When the materials are rubbed together, electrons are removed from atoms within the materials, giving rise to a static electric charge. For example,  when you rub a balloon on your head it causes opposite static charges to build up both on your hair and the balloon. Consequently, when you pull the balloon slowly away from your head, you can see these two opposite static charges attracting one another and making your hair stand up. Similarly, When a glass rod is rubbed with silk, electrons from the glass rod are transferred to silk. This is because the electrons are less tightly bound in glass than in silk. Thus, glass becomes positively charged due to loss of electrons and silk becomes negatively charged due to gain of electrons.

Generation Of Electricity Through chemical Action

Chemical reaction was the very first accurate and usable process devised to generate electrical energy. Luigi Galvani first discovered the process and published his results in 1792. In 1800, Alessandro Volta constructed the voltaic pile, the first battery, based on Galvani’s findings. The battery consists of an electrolyte (which can be liquid, solid, or semi-solid), a positive electrode, and a negative electrode. One of the electrodes produces electrons, and the other electrode receives them. When these electrodes are connected to a circuit an electric current is generated. There are two types of batteries. Voltaic/Primary batteries and Secondary batteries. Voltaic are the batteries in which chemical energy cannot be turned into its original form as it once converted into electrical energy. Secondary batteries are the batteries in which chemical energy can change back into its original form by passing an electric current through it in the opposite direction to the normal operation of the battery.

Generation Of Electricity Through Sunlight

The energy we get from the sun is called solar energy. Solar energy is a renewable energy because it will never end as long as the sun remains. It is also pollution-free because there are no harmful gases, chemicals, and fly ash produced. To convert sun’s energy into electric energy a semiconductor metal sheets are needed. They are called photovoltaic cells. These cells are coated with a transparent glass that allows radiation to pass through and minimizes heat loss, and have one or more layers of a semiconductor material. In the absence of light, the system does not generate energy. When sunlight hits the plate, the cell begins to function. The photons of sunlight interact with the available electrons and increase their energy levels. In this way energy is generated.  The result obtained can be improved using an inverter, which is responsible for transforming this energy into alternating current (ac), which is what we use in our homes. A photovoltaic cell can produce electricity even in low sunlight so there is no cut in energy even during rainy or cloudy day. Photovoltaic solar energy will be the cheapest source of electricity in the world.

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Generation Of Electricity Through Heat

Electricity generated through heat are called thermal electricity. To generate this type of energy thermal heat pumps are used. They are used to transmit heat to the earth depending on weather you want to heat or cool the environment. We can get steam in many ways, such as by burning coal, oil, gas, urban waste, or taking advantage of a large amount of heat generated by nuclear fission reactions. One of the exact technique to produce steam is to inject liquid water into earth’s interior area to increase its temperature. As a result of this liquid water is transformed into steam and returns to the power plant full of energy which is ready to generate electricity. The electricity produced in this way can be used depends on the characteristics of each source.

• High-temperature resources (over 150°C) are used to generate light.
• Below 100ºC they are used to supply electricity to heating/air conditioning systems.
•  Very low temperatures (less than 30ºC) its use goes directly for hot water.

Generation Of Electricity Through Pressure

Energy can neither be created nor destroyed, but it can transform from one form to another. Yes pressure can be transformed into electrical energy. Pressure as a form of potential energy can be used to run a turbine. Turbine can drive an electric generator. In turn, an electrical energy is produced in this process. In large ships electricity is generated  by exerting pressure on underground water and it is used as an alternative to main system.

Generation Of Electricity Through Magnetism

By observing how could a magnetic needle deflect electric current a Danish physicist, Hans Christian Oersted in 1819 discovers a connection between electricity and magnetism which was developed by a French scientist André Marie Ampère. After that  in 1831, the British scientist Michael Faraday discovered that the movement of a magnet in the vicinity of a cable induces an electric current in it. It was the opposite of that found by Oersted. But both discoveries was ground breaking. The complete blend of the theories of magnetism and electricity happened with the prediction of electromagnetic waves. It was predicted by British physicist James Clerk Maxwell. He predicted the existence of electromagnetic waves  and identified light as an electromagnetic phenomenon.

The spinning of the electrons around the nucleus of an atom forms a tiny magnetic field. The electrons in most objects rotate in random directions, and their magnetic forces cancel each other. As we all know the properties of magnet, that is if we put a north pole and south pole together in a magnetic field they will attract each other like protons and electrons. This property of magnets are used to form electricity.

Most electricity comes from generators that use magnetic fields to create electricity. These generators are made up of coils of wire that are either rotated through magnetic fields or are stationary around a shaft with rotating magnets. Electric magnets are iron or steel wound with wire. When electricity passes through the wire, the metal becomes magnetic and creates a magnetic field. The coils of wire of the generators are conductors, and when the electrons in the wires are exposed to changing magnetic fields, they move, creating an electric current in the wires. The wires are connected together, and the electricity eventually leaves the power station and goes on to power homes and factories.

Electricity and magnetism are closely related: power lines generate a magnetic field and rotating magnets in a generator produce electricity. But the phenomenon is actually much more complicated, because the electrical and magnetic properties of certain materials are also coupled with each other. The electrical properties of some materials can be influenced by magnetic fields, and vice versa. This is known as the ‘magnetoelectric effect’, and it plays an important role in various technological applications.

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Generation Of Electricity Through Water

Hydropower, or hydroelectric power, is a renewable source of energy that generates power by using a dam or diversion structure to alter the natural flow of a river or other body of water. It relies on the endless, constantly recharging system of the water cycle to produce electricity. There are different types of hydropower facilities, as they are all controlled by the kinetic energy of flowing water as it moves downstream. Hydropower utilizes turbines and generators to convert that kinetic energy into electricity, which is then fed into the electrical network to power homes, businesses, and industries. As hydropower uses water to form electricity, usually plants are placed near water source. The energy obtained from the moving water depends on the volume of water and change in elevation from one point to another. The greater the flow and the higher the elevation, the more the electricity that can be generated.

Generation Of Electricity Through Wind

 One of the cleanest ways of generating electricity is Wind Power. Wind use wind turbines to make electricity. Wind turns the propeller-like blades of a turbine around a rotor, which spins a generator, which creates electricity. A wind turbine turns wind energy into electricity using the aerodynamic force from the rotor blades, which work like an airplane wing or helicopter rotor blade. When wind flows across the blade, the air pressure on one side of the blade decreases. The difference in air pressure across the two sides of the blade forms both lift and drag. The force of the lift is stronger than the drag which causes the rotor to spin. The rotor connects to the generator, either directly or through a shaft and a series of gears that speed up the rotation and allow for a physically smaller generator. This translation of aerodynamic force to rotation of a generator creates electricity. There are two basic types of wind turbines. Horizontal axis turbines and Vertical axis turbines. Wind turbines can be built on land or offshore in large waterbodies like oceans and lakes. 

Power Generation System

Power generation systems are simply the combination of a potential or stored energy converter providing kinetic energy, which, in turn, creates electric power for use in motors, lighting, heating, and other conveniences of modern life.

There are three major classification of power generation system. They are:

• Thermal power generation.
• Nuclear power generation.
•  Hydro-electric power generation.

Thermal Power Generation

Steam power generation is a power generation method utilizing the expansion power of steam. Hot and high-pressure steam is generated from heat by burning heavy crude oil, LNG (liquefied natural gas), coal, etc. This steam is used to rotate the impeller in a turbine and activates a generator connected to the turbine to generate electricity. Steam power generation uses thermal energy with a relatively low temperature (600°C or lower).

Nuclear Power Generation

Nuclear generation is the only source of electricity that can produce a constant supply of power. A nuclear reactor produces electricity in much the same way other power plants do. The chain reaction produces the energy, which turns water into steam. The pressure of the steam turns a generator, which produces electricity.  In a nuclear energy plant, heat is produced from splitting atoms – a process called nuclear fission.

• Nuclear reactor creates heat that is used to make steam
• The steam turns a turbine connected to an electromagnet, called a generator
• The generator produces electricity

Hydro-Electric Power Generation

Hydropower plants capture the energy of falling water to generate electricity. A turbine converts the kinetic energy of falling water into mechanical energy. Then a generator converts the mechanical energy from the turbine into electrical energy. There are three types of hydroelectric power plants: They are:

• Run of the river power plants – withdraw water from the river based on the available water flow, which depends on environmental conditions, and run it through the turbines.
• Power plants with reservoir – regulates the amount of water going through the turbines and producing electrical energy year-round, independently of the water flow in the river.
• Power plants with pumped storage – power plants with two reservoirs at different elevations, which are operated when there is an extra demand of electrical energy. Water in the upper reservoir goes through the turbine and flows into the lower reservoir, and is later pumped back up to the upper reservoir at the time of day when there is not such a high demand of energy.

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