Methods Of Electricity Production Engineering Essay
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Electricity plays a major part in our society today. It is used in our hospitals, in our banks, in our homes, and in our cars. No matter what we do, we couldn't live without it. But all this electricity doesn't just appear at when we need it, we must create it. All over the world, there is millions of electricity generating stations. Some of these are small, others huge. Some of the stations run on the power of fire and steam, while others run on the power of the wind or falling water. Some even use the power of the sun alone to generate electricity. But with so many different ways to produce electricity, how do we know which ways are the most efficient and the most environmentally effective?
Electromagnetic induction is a phenomenon that occurs when a magnetic field intersects a piece of metal, most commonly a piece of wire, which can be affected by magnets. The most common method to induce is to create a magnetic field in such a way that the field intersects a coil of wire. This can be done in multiple ways, although the main two ways are to either pass a magnet through the center of a coil of wire, or to move a coil of wire in a magnetic field. However, if both the coil of wire and the magnet are both stationary, no electric current will be produced. The circuit must also be closed for a current to flow. The most efficient way to produce a current is to rotate a coil in a magnetic field. There is three ways that the amount of power generated by electromagnetic magnetic induction can be increased:
Increasing the strength of the magnetic field.
Increasing the amount of turns in the coil that is being affected by the magnetic field.
Increasing the speed at which the magnetic field intersects the coil.
In most power stations however, the generators used spin the magnets, or in most cases, electromagnets, around the wire. This enables a greater amount of coils to be used without the need to rotate a greater mass. The stations use turbines to rotate the magnets or coils.
To rotate the turbines, a power source is needed. There are four main power sources that are used:
Coal burning power stations use coal that has been mined out of the earth. This coal is burnt to create heat. The heat makes water evaporate into steam. As the steam rises, it hits rotors which spin the turbines.
Nuclear reactors work in somewhat the same way as a coal burning power station. These power stations use the power of a nuclear reaction to create the heat needed to boil the water that then turns to steam, which then turns the turbines. When the water is heated however, it becomes radioactive. This means that the water must be kept in a separate chamber to the water that will turn to steam. The radioactive water heats the clean water by means of conduction.
Wind farms, as they are commonly called, use the power of the wind to rotate massive rotor blades. These rotor blades turn a shaft that is connected to a generator, thus producing electricity.
The most common of power stations that utilize gravity are called hydro power stations. These use falling water to turn the turbines at the base of a mountain. As the water comes down the mountain, it is pulled by the force of gravity, making it travel at high speeds, which turns the turbines faster, which makes more electricity.
Another power source that is used to create electricity is the energy produced from the Sun. Solar panels collect solar radiation from the sun and actively converts that energy to electricity. Solar panels are comprised of several individual solar cells. These solar cells function similarly to large semiconductors and utilize a large-area junction diode. When the solar cells are exposed to sunlight, the junction diodes convert the energy from sunlight into usable electrical energy. The energy generated from photons striking the surface of the solar panel allows electrons to be knocked out of their orbits and released, and electric fields in the solar cells pull these free electrons in a directional current, from which metal contacts in the solar cell can generate electricity. The conversion of sunlight to usable electrical energy is called the Photovoltaic Effect.
After the electricity has been generated, it needs to be transmitted around the country. When electricity passes through a wire, some of the energy is lost as heat energy. In small devices, this is generally ignored because the wires are short enough for the energy that is lost as heat to be quite minimal. When the length of the wire increases, the amount of energy that is lost as heat also increases. This can be a problem when the wires are spanning thousands of kilometers. The reason for the lost of energy as heat is because of the current. This means that current is proportional to heat lost. Since this is the case, if the current is dropped to almost zero, then the energy lost as heat will also drop to almost zero.
This can be done with the use of transformers. Transformers work on the law of magnetic induction. This is done by passing a magnetic field through a primary coil of wire. The magnetic field produced by the current can be used to create a current in a secondary coil. If there is twice the amount of coils in the secondary coil as there is in the primary coil. The current will be halved and vice versa. When the current is lowered, the process is transformed is referred to as a step-up transformer, and when the current is doubled, it is a step-down transformer.
When the current is changed, the voltage is also changed. This is because current is inversely proportion to the voltage. This means if the current is halved, the voltage is doubled. This means when a step-up transformer halves the current, it doubles the voltage. To get the current as low as possible, the current must be brought up to around two hundred and twenty thousand volts.
Aim: To research the amount of energy three different types of power plants produce and compare their environmental impacts.
Three main power plants from within the state of Queensland were chosen to be examined. The plants chosen were; Tarong coal burning power plant, Wivenhoe hydroelectric power station, and the Hillcrest Christian College solar panel power plant.
Research on these specific power plants was completed by using in-class and as homework.
When all the needed research was acquired, the data was examined and a conclusion was drawn on which plant provided the most power, which plant was the most environmentally friendly, and which plant had the least intensity+.
Three sets of data have been collected:
Tarong Power Station*#
Wivenhoe Power Station*#^
Hillcrest Power Plant
+: Pounds of CO2 emitted per megawatt-hour of electricity produced.
*: The data collected also was coupled with a projected output for the next decade
^: The power station plans on a future upgrade that will produce carbon pollution
#: Average decade output
This data was put in the corresponding tables for comparison.
By looking at the data above it two main points can be made:
When the Tarong and Wivenhoe power stations are compared, it can be observed that the Tarong coal burning station produces a far larger amount of energy. It must be kept in mind that the Tarong station is a far larger station when compared to either of the other to stations examined, with the Tarong station having a maximum power output of over 1400MW, where as the Wivenhoe station has a maximum power output of only 500MW, and the Hillcrest plant's power output depends on the intensity of the sunlight it receives. Even if the maximum output for the Wivenhoe station was over three times the size, putting the maximum output to 1500MW, theoretically, it would still be producing less energy than the Tarong station. It would also be highly unfeasible to achieve the same energy output with the Hillcrest plant as the maximum power output would have to be increased by at least sixteen million times. This puts the Tarong coal burning station as the most economically effective power station out of the three.
At the current date, both the Wivenhoe station and the Hillcrest plant are producing no carbon emissions at all, where as the Tarong station is producing a very high amount of CO2. This puts the Wivenhoe station and the Hillcrest plant on equal ground in this aspect. In the future however, the Wivenhoe station is planning on installing upgrades to their station which, presumably, will force the plant to start giving off CO2 emissions. Up until these upgrades are made, the two stations are on the same level with CO2 emissions, but as soon as the upgrades are made, the Hillcrest solar power plant will be the most environmentally effective out of the three stations researched.
Even though all the power stations that were examined are the few main ways that energy is generated in our current society, there are many other ways that the energy that we use gets generated. These consist of power stations that use means of; Biomass energy, wind energy, nuclear energy, tidal energy, combustion energy. These ways are examined in more depth below:
Biomass energy uses the biodegradable waste products of our everyday lives, such as plant waste or animal matter, to create either a thermal or chemical conversion. During these conversions, the matter undergoes chemical reactions that produce either heat or other chemicals that can be used in other items. This method of "green energy" is very environmentally friendly as it takes the form of what typically happens in our natural world, decomposition for example.
The use of giant propellers to catch the force of the wind and use that force to turn a generator is the way wind turbines work. In theory the idea of using the power of something as ambient and as reliable as the wind is one of the most environmentally friendly methods to create electricity that is around. This is because there is no byproducts of any sort and the wind that is used can never be depleted. The major problem with using this as an energy source is the strength of wind needed to spin the propellers. This is because although there is wind everywhere in our world, the strength of this wind, on the most part, is not always strong enough to rotate the propellers due to their immense weight.
Nuclear energy is one of the most dangerous forms of generating energy that we have in our current society. When it is harnessed properly and efficiently, it is also one of our most effective ways of producing energy. The basic concept of a nuclear reactor is similar to that of a coal burning station, to create heat to make steam to turn turbines. One major downfall with these power stations is the waste the produce. This waste is not CO2, but is radioactive waste that, if dispersed of correctly, would provide our society with a clean and efficient way to generate power, although this is not the case in the present time. Until there is a way to dispose of the nuclear waste efficiently, nuclear power will not become our primary source of power.
Tidal energy is a form of hydro power that converts the energy of the tides into a useable form of energy. Although this method is not widely used, it has great potential for the future of power generation. This is because the tides are far more predictable than the wind and solar energy. Tides are so predictable in fact; that we can tell exactly what they will be doing in two hundred years. The principle behind tidal power is the same as that of wind power. Underwater propellers are used to capture the energy of the flowing water, which is then converted to power by large turbines.
This form of energy is just as clean as wind energy, but also has the additional benefit of not creating a poor spectacle as most of the generator is hidden underwater, instead of out in the open.
Also called mechanical energy, this is the act of using natural gasses or conventional fuels to power a combustion engine which then is used to rotate a turbine. This method is most commonly seen in small or backup generators that are made for private or commercial use. Two side effects of this type of energy is the noise that is made during combustion, and the byproduct of CO2. On the most part, these generators are used mainly in the form of small, portable types. This is because the forces that would need to be dealt with on a large scale generator are quite large and can be potentially hazardous.
When all the data is examined, hydroelectric power stations proved to be not only the most environmentally safe, equal with solar power, producing zero CO2 emissions, but it also was able to decent a fair amount of power. Even though the coal burning power station produced a lot more power, almost an eightfold on what hydro station produced, the hydro station produced zero percent of the emissions that the coal burning station did. In this respect, if the hydro station was to be increased to eight times its current size, theoretically, our society would be provided with more energy than the coal burning station produced, along with no emissions or byproducts. In contrast, the solar power plant also gave off no emissions, although the amount power produced was quite unsubstantial in comparison. As discussed earlier, the solar power plant would have to create eighteen times the amount of energy that it currently is producing to be a contender in power generation, but doing this would mean that the size of area needed would be on the same scale of increase. This is feasible in terms of installing solar panels on every roof in our major cities for example, although the costs of doing such a thing would be far greater than that of upgrading the hydro power plant.
It is recommended that the use of hydroelectric power stations is continued and their usage is increased. This is not only a one of the more environmentally friendly types of renewable energy, but it is also one of the more reliable according to the research completed. This method does not produce byproducts of any kind and does not make waste of any of the resources used in the production of power that is generated.
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