Introduction
The modern world relies on vast amounts of power to operate. Electricity is utilized for many domestic and industrial purposes, making it a core part of modern life. Breeze (2005) suggests that the modern world “is a result of the discovery and exploitation of electricity” (p.10). New appliances that require electricity are being developed, and industrial growth is creating a higher demand for power. While new and existing power sources are being exploited to supply electricity, the demand for electricity is increasing at a higher rate.
As a result, governments and the power generation industry are constantly looking for feasible power production resources to exploit. Power generation has become an important area for the development of society. This paper will set out to define power generation and then proceed to discuss some of the most important electricity generation technologies. The paper will highlight the major advantages and disadvantages associated with these major sources of power.
Power Generation
The power generation industry has experienced great growth in the twentieth century. By definition, power generation is the “process of creating electricity from other forms of energy” (Jonsdottir, 2013, p.80). It is necessary to convert the energy from its original form to electricity. Only then can the various appliances created to use electricity as the power source utilize it. Industries also rely on power in the electrical form to operate.
Power generation is, therefore, important for the development of society. A wide variety of sources can be exploited to generate electricity. Power can be generated from renewable and non-renewable resources. Renewable sources of energy can be renewed continuously in a natural way.
Non-renewable sources cannot be regained naturally, and once they are used, they become depleted. In recent decades, efforts have been made to increase the energy output from renewable energy resources while reducing the use of non-renewable sources (Jonsdottir, 2013)
The power generation industry tries to obtain energy in the most efficient way. However, it is not possible to harness all the energy produced from a specific source. The laws of physics dictate that some energy will be lost during the generation process (Tagare, 2011). In scenarios where a turbine is used to generate electricity, energy is lost due to friction and heat.
Power System
A power system is a well-developed network for the supply and transmission of electricity from the point of generation to the end consumer. The system links the production plant to domestic consumers or industries (Sivanagaraju, 2010). Power often has to be transmitted through long-distance since power generation sites are often located away from residential and commercial areas.
High voltages are used to reduce the transmission losses experienced and therefore, improve the efficiency of the system (Sivanagaraju, 2010). A country needs to make a huge investment in the infrastructure for its power supply system. Components such as high voltage lines, step up transformers and step down transformers need to be included in the power supply system.
The power system of a country relies on several power sources. Through power generation, energy is converted from sources such as wind and water into electricity (Tagare, 2011). The electricity is then fed into the grid and supplied to the consumers. Large-scale power is often created by turning a large turbine using a variety of techniques. Some of these techniques are discussed below.
Hydropower Source
Hydropower is one of the oldest sources of electricity. Breeze (2005) reveals that hydropower entered the power generation scene at an early stage in the development of the electricity industry. This source is clean, economically feasible, and renewable. Hydropower works on the concept that water streaming down from higher to lower levels consists of potential energy in itself because of its altitude (Wagner & Mathur, 2011). This energy is converted into kinetic energy while flowing downhill.
Hydropower plants can be categorized according to the source of water. One type of hydropower plant is the river power plant. This type of plant generates electricity using the natural flow and elevation drop of a river. The power plant is fed directly by a river, or a diversion canal can be built to feed the power plant. A short penstock or dam might be built to direct the water through the turbines (Breeze, 2005). In this system, the natural flow of the river remains relatively unaltered since most or all of the water is allowed to flow downstream after it passes through the turbines.
Another type of hydropower plants is the storage power plant which entails an extensive impoundment of water at the power plant or the reservoir upstream. Water is stored during high-flow periods, and it is used to augment the flow during low-flow periods (Wagner & Mathur, 2011).
As a result, the plant can generate a relatively constant supply of energy all year round. There exist pump storage facilities which involve the pumping of water from a lower reservoir to a higher one. The water is pumped during off-peak hours, and they ensure that there is enough water in the more upper reservoir during the peak period.
Ocean waves can also be harnessed to produce electricity. Oceanic power plants have also been developed to make use of the energy contained in tides. These tidal power plants have turbines positioned to utilize the kinetic energy of water during high tides and low tides. Cleveland (2009) reveals that tidal power plants are hard to implement since it is not possible to build a dam to provide water for turning the turbines during low tides.
Merits of Hydropower
A major advantage of hydropower is that it is obtained from water, which is a renewable source of energy. Generating this form of power does not require the use of scarce fuel reserves. In addition to this, hydropower is clean power. In the generation of this power, there is no air pollution or radioactive waste problem to be dealt with. Since water does not produce any greenhouse gas, hydropower does not contribute to global warming.
Another significant advantage of hydropower is that is has a higher efficiency compared to other power sources that utilize thermal energy. Wagner and Mathur (2011) document that hydropower has an efficiency of over 90%, while thermal energy has an efficiency of only 45%. The high efficiency of hydropower is because the water is used to directly turn the turbines that generate electricity.
Hydropower represents approximately 25% of the total electrical energy generated worldwide. However, there is a huge hydropower potential existing in the world. Cleveland (2009) states that if all the feasible hydropower potential is exploited, this power source could contribute over 50% of the total energy needed by the world.
Demerits of Hydropower
In spite of its significant advantages, there are some limitations associated with hydropower. To begin with, hydropower relies on fast water currents that are often found in hilly areas. Extra investments, therefore, have to be made for installing long transmission lines from these remote areas to the urban areas where the electricity is needed. Large hydropower plants require the creation of large dams to store the water needed for power generation.
These dams may cause earthquakes due to the heavy concentrated load on the earth (Chiras, 2004). In addition to this, the large dams are a hazard during heavy rains since the water levels in the dam rise to unsafe levels. If the dams are damaged, they create devastating floods in the downstream side.
Even though hydropower is a clear alternative to power produced through fossil fuels, the ecological impact of hydropower can be significant. Cleveland (2009) explains that the dams and reservoirs required by most hydroelectric power facilities significantly alter the aquatic habitat and the species present. A dam can hinder migrating fish species since the waterway is blocked. The dams also cause water quality problems such as dissolved gas bubble disease.
Wind Power source
Wind power technology is another old form of energy generation. Thousands of years ago, the Egyptians used wind energy to operate windmills for grain processing. It is possible to tap wind energy to generate electricity. The components that makeup wind power systems are propeller blades, rotors, and support towers.
The propeller blade is the part of the system that is driven by the wind and made to rotate at various speeds depending on wind speed. Simon (2007) reveals that some propeller blades are designed such that they are capable of generating significant amounts of electricity even in light winds. These blades are constructed from strong, lightweight materials such as fiberglass and maintained at an optimum pitch.
The rotor is the central feature of the blade assembly. It controls the blade pitch allowing the wind power user to adjust pitch depending on wind speed and direction. The rotor assembly also contains a system of gears that mechanically increase the rotation speed of the electrical generator. Simon (2007) reveals that the system of gears can achieve high rotation speeds within the generator unit, creating electricity.
The last part of the wind power system is the tower. Wind energy towers are important in the energy generation process since they influence the ability of the propeller blade to capture wind energy. The height of the tower is often determined by the length of the propeller blades and the size of the rotor assembly (Cleveland, 2009). The height of the tower is set such that the wind power system will receive optimum wind speed.
Many wind turbines are needed to produce a significant amount of power. Simon (2007) documents that “increasing the number of turbines in a single location does not necessarily improve the ability of wind systems to meet peak load demand” (p.143). On the contrary, accumulating many wind turbines in a particular site hurts energy generation.
As the wind turns the propellers in the wind power system, its energy is reduced, leading to reduced energy levels for subsequent turbines. Greater geographical diversity in wind turbine sitting will, therefore, lead to better energy production levels. In addition to this, multiple wind energy production sites take advantage of the variation that exists in wind speeds over a large geographical area.
Merits of Wind Energy
Wind energy offers several significant advantages. To begin with, wind resources are available on every continent. This is in contrast to other forms of energy such as fossil fuels which are only available in certain parts of the world. Chiras asserts that “tapping the globe’s windiest spots could provide 13 times the electricity now produced worldwide” (354).
Researchers estimate that the wind available in the States of North Dakota, South Dakota, and Texas is enough to supply all the electrical demands of the United States (Chiras, 354). Exploiting wind energy makes use of only a small amount of land. In a typical wind farm, only 10% of the land will be used for building the turbines and the relevant infrastructure.
The rest of the land can be used for farming activity. In addition to this, wind power generation plants are safe to operate. Due to the wide availability of wind and the cost-effectiveness of wind power generation, the wind is becoming the fastest growing source of energy in the world.
Demerits of Wind Power
A significant disadvantage of wind power is that its efficiency cannot be guaranteed. While wind power appears to be a good source of free energy, it is impossible to control or accurately determine its occurrence. Various natural occurrences such as rainfall and cloud cover can affect the speed and direction of wind received on a wind farm.
This presents a major challenge since consistency and reliability must be guaranteed if wind power is to be used to provide electricity to the industries and households (Chiras, 2004). Wind turbines produce a lot of noise, which makes them a major source of noise disturbances. The propellers make noise as they rotate constantly, and the rotors contribute to additional noise generation. The noise produced by wind turbines makes it undesirable to set up wind farms near areas where there are human settlements.
Nuclear Power Source
Nuclear power is generated from the process of producing heat from nuclear reactions. This heat is then exploited to produce electricity. Nuclear power generation was developed following the advances made in the nuclear weapons industry. After the successful implementation of the atomic bomb, scientists started to look for ways to harness nuclear power for civilian applications. They hoped to be able to exploit the vast amount of energy produced by nuclear reactions for productive purposes.
Nuclear power generation is achieved through fission or fusion reactions. Modern power stations have been able to exploit the fission process to produce electricity (McKinney & Schoch, 2012). Nuclear fission entails the splitting of radioactive isotopes of heavy elements such as uranium and plutonium. The atoms are divided into two or more smaller nuclei that repel each other and travel at high speeds colliding with other atoms. This creates a chain reaction, and great energy is obtained.
Nuclear power plants require huge amounts of energy to begin the atom splitting process. The power plants make use of a machine that is capable of discharging neutrons at atoms at a high velocity. The plant also has a reactor which has the nuclear fuel at its core. Control rods made of a material that readily absorbs neutrons regulate the rate of reaction at the core (Hore-Lacy, 2011).
These control rods regulate the rate of reaction, therefore, ensuring that the chain reaction does not go on in an uncontrolled manner. If the chain reaction is allowed to go uncontrolled, it will result in a nuclear meltdown.
When in operation, the reactor produces tremendous amounts of heat energy. The nuclear power plant uses water to cool the core by taking away some of the heat. The nuclear power plant has water in a primary and secondary loop. The primary loop is the tube that circulates nearer to the core (Lyon, 2011).
The water from this loop is in direct contact with the core as it cools it. The primary core absorbs the reactor core’s heat energy and therefore, becomes superheated. The secondary loop also contains water, but it is not in direct contact with the primary loop. Instead, a heat exchanger is used to take the heat from the primary loop and transfer it to the secondary loop. The heat turns the water in the secondary loop into steam, and this is used to turn turbines. The turbines generate electricity that is fed into the main grid.
Merits of Nuclear Power
Nuclear power can satisfy the growing global electricity demands. Hore-Lacy (2011) reveals that the global electricity usage is going to double within 20 years. Conventional forms of power generations will be unable to provide this enormous energy supply. Renewable power sources such as wind and solar cannot be relied on to provide continuous, reliable energy. Nuclear energy is the only feasible solution with the potential for providing continuous energy for decades to come.
Nuclear power also assists in the reduction of the negative environmental impacts caused by fossil-fuel operated power generation plants. Nuclear power plants also increase the energy independence of a country. Once the power plant has been built, the country can generate its power. This increases the energy security of a country since it does not have to rely on the energy resources of other countries.
Demerits of Nuclear Power
The nuclear power source is non-renewable meaning that it will run out at some point in the future. While nuclear fuel is available in significant quantities, it is predicted to run out in about 100 years (Loyn, 2011). Once the supplies of nuclear fuel are over, it will not be possible to operate nuclear power plants. In addition to this demerit, nuclear power plants produce toxic waste substances. If this radioactive waste is not disposed of carefully, it can cause major harm to the environment.
Boiler and Turbine system development at Power station
Thermal electricity power generation is the main source of electricity in the world today. While a variety of fossil fuels are used to generate heat, coal is the main fuel used to heat the boilers and generate steam. Coal is preferred since it is relatively cheap and widely available in various locations all over the world.
Boilers have been used to generate electricity for more than a century. In the initial states, coal-fired power stations were used (Breeze, 2005). The basic principle used was to burn coal in the air and use the heat generated to heat water. The water then turns to steam, and this steam is used to drive turbines. The rotation of the turbine drives a generator, therefore, creating electricity.
The traditional coal-fired power plant is made up of a furnace boiler and a steam turbine generator. The coal is put into the furnace where it burns, producing heat energy. There is a water system running across the furnace, and this system absorbs the heat released from the coal.
The steam is directed into a turbine engine, and it turns the blades of the turbine, therefore, generating electricity. The basic traditional boilers led to significant environmental damage as coal was burnt into the atmosphere (Breeze, 2005). Modern boilers are therefore made with environmental concerns in mind.
Modern boilers are also designed to be highly efficient. One point taken into consideration is that the efficiency of a boiler increases with an increase in steam pressure and temperature.
Modern boilers are therefore made to withstand high temperatures and pressures. Breeze (2005) documents that while early boilers were made of iron, “modern boilers are made of special steels that can resist the high temperature and pressure conditions encountered in the power plant” (p.154). This makes the modern boiler and turbine system more efficient in operation.
Conclusion
Power generation is integral for the sustenance of the modern society. This paper set out to discuss various sources of power and explain how they work. The paper began by acknowledging that electricity has become an integral part of the modern world. It then proceeded to define power generation and power systems. Governments and power companies have to seek many viable options to cater to the growing electricity demands.
The paper revealed that power generation assists in the conversion of energy from various forms into electricity. It then discussed the main sources of power, which are: hydropower, wind power, and nuclear power. It has noted that these sources can supply a great amount of electricity into the grid.
These energy sources are attractive since they can be exploited in numerous locations all over the world. Technological advances have made it possible for power generation companies to derive a significant amount of power from these sources. Utilizing these power resources will provide the needed energy to satisfying the growing global demand for electricity.
References
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