Solar Energy Use in Africa - Essay Example

? Solar energy use in Africa number Solar energy use in Africa Most of the human activities since time in memorial have beenpowered (energized) by non-renewable sources of energy. The non-renewable sources of energies that have been used by mankind since time in memorial include: nuclear sources of energy and fossil fuels among others (Richards 2010). In addition to being non-renewable, these sources of energies have been associated with environmental degradations and problems (House-Soremekun & Falola 2011). For example, according to Richards (2010) fossil fuels have been associated with air pollutions and global warming. These sources of energy, particularly oil, have also been associated with water pollution as well as destruction of marine life and diversity through oil spills in oceans, seas, rivers and lakes among others. Even most of the existing renewable sources energies such as geothermal, wind and hydroelectric have been extremely expensive to install. In addition, these sources of energies are normally extremely affected by changes in weather conditions. Also, their abundance as compared to that of the solar energy is limited. Due to the problems associated with the available sources energies such as fossil fuels, nuclear, wind, hydroelectric and geothermal, the use of solar energy is becoming popular in most parts of the world, particularly in China and Africa (House-Soremekun & Falola 2011). The solar energy seems to the source of energy that is more sustainable as compared to other sources of energy (Richards 2010). This paper, therefore, aims at discussing the use of solar energy in Africa and basics of this source of energy. Africa receives more solar radiation than any other continent in the world, thereby making it the continent with the greatest potential than any other continent in the world. Sun shine in Arica is virtually uninterrupted, and one of the most abundant energy resources in the continent. However, this precious source of power has not been fully exploited in the continent for number years. Despite the abundance of this energy resource, it is estimated that about 2 billion individuals (people) in world (most of them from Africa) either struggle or fail to meet their daily energy requirements due to scarcity of supply of energy (Richards 2010). Even though there has been reluctance in the harvesting of solar energy in Africa, the situation seemed to have change to day since a number of organizations in Africa as well as African governments have been turning their attention towards renewable and sustainable sources of energy. Amongst the renewable sources of energy that have been greatly focused by the African countries is solar energy. Africa as continent has made number of milestone towards harvesting solar energy. For example, the headquarters of United Nations Environmental Program (UNEP) based in Nairobi (Kenya) is fully powered by solar energy (House-Soremekun & Falola 2011). Further according to House-Soremekun & Falola (2011), South Africa and Ghana are also planning to build amongst the biggest solar power plants in the world. Solar energy is also known as the radiant light, and it is referred to as heat energy from the sun (Richards 2010). This energy can be converted by different transducers to produce different sources of energy. For example, solar energy can be converted directly to electric energy by use of solar cells (also known as Photovoltaic). This particularly important for small scale energy requirements such as for watches and calculators. The solar energy can also be directly used to heat water for both domestic and industrial use. In addition, solar energy can be used to produce large amounts of solar energy through the use of solar radiation concentrators such as parabolic troughs. We have discussed how solar energy is converted into electric energy or used as heat energy to heat water among others (Hantula 2010). The question that might probably be lingering in the mind of the reader is how this precious energy is formed in the sun. The sun has an intense gravitational force. At the core of the sun this gravitational force creates enormous pressure since everything is pushed towards it (Richards 2010). This pressure is so high that it forces hydrogen atoms to come together; this reaction is known as nuclear fusion. When two atoms of hydrogen are forced together in this reaction, helium-4 is formed; energy is also formed in this nuclear reaction. It is important to mention that this nuclear reaction takes place in three steps. The resulting atoms of helium-4 when compared atoms of hydrogen that started the reaction, they are less in mass. Therefore according relativity theory of Einstein (E=mc?), the difference in what is converted into solar energy. This solar energy is then emitted in different light forms (energy) namely: X-rays, infrared, radio-waves, microwaves and ultraviolet light among others (Richards 2010). The conversion of hydrogen atoms into helium-4 contributes to approximately eighty five (85 per cent) of the total energy produced by the sun (Richards 2010). The solar energy output from the sun has been constant since time in memorial. However, though negligible, there are some variations in output of this form of energy; the variation is estimated to be about 0.2 percent (GSU 2011). The graph 1 in the appendix shows solar energy out since 1975 up to 2007. Now that solar energy has been produced by the sun, the question that might arise from is how is it extracted and used by humans. Solar energy can be extracted using three main methods, and these methods normally depend on the use the extracted solar energy will be put (Richards 2010). First, solar energy can be extracted by use solar cells (photovoltaic cells). The main idea behind the extraction of solar energy in the production of electric energy via the photovoltaic cells is that solar energy (radiation) mobilizes electrons on the surface a semiconductor material such as silicon, thereby initiating the flow of electric current (FSCE 2007). Typically a photovoltaic cell made of silicon as the semiconductor materials has two layers one thin and the other thick (Hantula 2010). The thin layer, which is made of phosphorus-doped silicon, is usually placed on top of the thick layer (made of silicon which is doped with boron). This arrangement creates an electric field at the top of the cell. When the electric field is stricken by the sun’s radiations, electrons flow through the circuit, thereby enhancing electric current flow. The process and the arrangement of solar cell are as shown in figure 1 in the appendix of this paper. When several photovoltaic cells are arranged and interconnected to together they form a solar panel (also known as photovoltaic panel or solar model) (Hantula 2010). These photovoltaic cells are usually connected or arranged in series in order to produce the desired amount of voltage. They can also be arranged in parallel in order to the desired electric current. Most of the solar panels are made of crystalline silicon cells which are based on wafer. Some solar panels are made of thin-film cells which may be based on silicon or cadmium telluride. In order to enhance rigidity of solar panels, they are usually reinforced using structural members. They can be reinforced on either the top or bottom. The cells of a solar panel are also protected against moistures and mechanical damages. Now that we know how solar panels work, what is the relationship between dimensions of solar panels and the total electrical power output? Normally the large the area a solar panel covers, the more efficient the solar panel (the more power it produces) (Hantula 2010). It is for reason that solar panels are rated in terms power/squire meter (power per unit area of a solar panel). This solar panel rating is known as solar irradiant. Averagely, modern solar panels (photovoltaic modules) are designed to produce between 8 and 10 watts (9 watts on average) of energy per the square foot of the area of the solar panel. This is expressed as shown in the equation below: For example, a solar panel that measures 25 feet by 20 feet will produce solar energy whose value is as calculated below: Area of the solar panel, Power output, The produced solar energy can be stored in batteries for use when solar energy (radiation) is out of reach, particularly at night (Hantula 2010). The energy produced in form can also be directly used to power light electronics such as calculators, watches, solar bulbs, Televisions and radios among others. Just as any other source of energy, solar energy has merits and demerits. One of the demerits of using solar panels as source of energy is that these equipment need relatively large spaces in which they would be installed, therefore, lack of sufficient space normally limit their installation (Hantula 2010). Secondly, if these panels are to be installed on the roofs of buildings and structures, additional reinforcements may be required in order to sustain the weight that would be added by the solar panels. Otherwise, the safety of houses or structures in which these panels have been stalled may be compromised. Another disadvantage of solar panels as source of electricity is that if they are used as standard by sources energy, additional electrical installations may be required. This process may be complicated, particularly for electrician in charge of rewiring the structures in which the solar panel would be used as backup power. Another disadvantage of solar panels as sources of electricity is that they can be extracted at night, or the amount extracted during overcast days may little to sustain the requirements. This demerit has, however, been offset by the availability of solar batteries which can the solar power and be used during night times or times when the amount of solar energy available is small. The advantages of using solar panels as sources electricity by far offset their disadvantages. First, Solar panels do not have moving parts, therefore, do not easily breakdown. This means that they require minimal maintenance, therefore, they can work for long periods of time without giving them attention or focusing on them (Hantula 2010). Secondly, solar panels do not cause environmental degradations like nuclear energy and fossil fuels. Another advantage of solar panel is that this device can last for long periods of time with minimal running costs. If large scale electrical energy is required from the sun, the solar energy can be collected by use large parabolic or specially arranged mirrors (Hantula 2010). The collected energy is directed or concentrated into tower in which water is heated to produce steam. The steam energy is then used to drive turbines which in turn produce electric energy. Figure 2 in the appendix shows a typical process of converting solar energy into steam energy and finally to electrical energy. Thirdly, solar energy can be collected by use of solar collectors. These solar collectors can be used to heat as well as supply homes with hot water (Hantula 2010). The process is as shown in the figure 3 in the appendix. Is all energy produced by the sun reach the earth? This might be a question that lingers in the mind of the reader. The planet earth receives approximately 174 X 1015 watts of solar energy. Of this, about seventy percent (70%) reaches the surface of the earth and is absorbed by land, clouds and oceans (Richards 2010). This is the energy whose portion has been used to enhance human life. The rest of the solar energy is reflected back into the space. The solar energy that is absorbed by the land, clouds (atmosphere) and oceans normally raises their temperatures. The solar energy is amongst the most sustainable sources of energy in Africa, in fact compared to other renewable sources of energy such wind and hydro (water) sources of energy, it seems that it is more sustainable and cost effective. Also, being that it does not pose any danger to environment like other sources of energy such as fossil fuel and nuclear energy, it should be adopted (particularly in Africa where access to other sources of energy is limited) as the main source of energy. This will not only save the planet earth from frequent degradation but also save people from costs associated with energy consumption. References FSCE., 2007. How PV Cell Work. [online] Available at: Florida Solar Energy Center: http://www.fsec.ucf.edu/en/consumer/solar_electricity/basics/how_pv_cells_work.htm [Accessed February 25, 2013] GSU., 2011. Correlation of global temperature with solar activity. [online] Available at: Georgia State University: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/solact.html [Accessed February 25, 2013] Hantula, R., 2010. How Do Solar Panels Work? New York: Infobase Publishing. House-Soremekun, B., & Falola, T., 2011. Globalization and Sustainable Development in Africa. New York: University Rochester Press. Richards, J., 2010. Solar Energy. New York: Marshall Cavendish. VDO., 2012. Production of electricity from solar energy. [online] Available at: Visual Dictionary Online: http://visual.merriam-webster.com/energy/solar-energy/production-electricity-from-solar-energy.php [Accessed February 25, 2013] VDO., 2012. Solar houseclick to hear. [online] Available at: Visual Dictionary Online: http://visual.merriam-webster.com/energy/solar-energy/solar-house/solar-house.php [Accessed February 25, 2013] Appendix Graph 1: Solar energy out since 1975 (from: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/solact.html) Figure 1: a photovoltaic cell (from: http://www.fsec.ucf.edu/en/consumer/solar_electricity/basics/how_pv_cells_work.htm) Figure 2: Use of heliostats (specially arranged mirrors) to concentrate solar heat (from: http://visual.merriam-webster.com/energy/solar-energy/production-electricity-from-solar-energy.php) Figure 3: The use of solar collectors to collect solar energy and used to heat water for home (from: http://visual.merriam-webster.com/energy/solar-energy/solar-house/solar-house.php) Read More