Generation of electrical power through solar technology involves the conversion of energy in the sun’s radiation into electricity. The sun emits electromagnetic radiation which contains energy in the form of photons. Solar panels harvest this energy and convert it to electricity though a phenomenon referred to as the photovoltaic effect. A solar panel is made up interconnected solar cells, which are in turn fabricated from millions of light sensitive p-n junction diodes. The diodes are made from doped semiconductor materials such as crystalline silicon. Doping silicon with an impurity such as phosphorous introduces charge carries referred to as electrons and holes. When a dopant material introduces excess electrons into the semiconductor, the free electrons act as the charge carriers and are referred to as the majority charge carriers. Conversely, when a dopant takes up all electrons and creates a deficit of electrons, the holes become the majority charge carriers. Exposure of the photovoltaic diode to sunlight causes the charge carriers to jump from one side of the p-n junction to the other thereby creating an electric current. This is a paper on solar energy and its efficiency and benefits.
Energy generated by photovoltaic solar panels can be used for domestic applications or fed to the national grid depending on the type of system used for power generation. There are two types of solar systems, rooftop solar and ground-mounted utility-scale solar. Rooftop solar consists of an array of solar panels mounted on the roof and the power produced is used to power electrical appliances in the house such as fridges and televisions. Also, surplus power can be fed to the grid through an agreement with the grid operator known as power purchase agreement (PPA). This phenomenon is known as net metering whereby a meter logs the power that flows either into the house or is fed to the grid. The grid operator then compensates solar system owner for the units of power fed to the grid according to the feed-in-tariff agreed between the two parties. On the other hand, utility-grid solar plants consist of thousands of interconnected panels mounted on the ground. All the power from such plants is fed to the grid, and the grid operator compensates the project developers for every unit of power generated.
Challenges facing solar energy and their solutions
Solar energy technology is maturing as a method of main stream energy generation. In the Unites States, the installed solar capacity has increased seventeen times since 2008 from 1.2 gigawatts (GW) to the current 20 (GW). The Department of Energy in the United States estimates that this is enough energy to power 4 million homes (par. 1). According to the Solar Energy Industry Association, the growth in solar energy has been encouraged by the decreasing prices of solar panels (par. 3). In earlier years, solar panels were prohibitively expensive and as a result, many would-be buyers shied away from solar energy. However, the cost of solar panels have shot down within the recent few years and by 2014, solar panels cost 50% less of their former prices three years earlier as shown in figure 1 below.
Figure 1: A comparison between the installed capacity of solar and the prices of solar panels between 2005 and 2014. Source: Solar Energy Industries Association.
Apart from the high cost of solar panels, another factor that has derailed the uptake of solar energy is the low conversion efficiency of solar panels. As a result, the low efficiency leads to low energy density in solar as compared to other methods of energy generation such as hydropower and nuclear energy. The most efficient solar panels on the market today has a maximum efficiency of about 20% while the most common and affordable panels have an efficiency range of 11% to 15%. A panel with 20% conversion efficiency converts only 20% of the radiation energy to electricity while the rest is converted to heat or reflected away (Institute for Energy Research par.5). The low efficiency of solar panels necessitates the use of a large number of panels for ample power to be generated. As a result, large spaces are required to mount the solar panels which limits access to solar energy for people with limited or no rooftop spaces.
Benefits of solar energy
Solar energy is beneficial to both the environment and the economy. For example, solar is a renewable form of energy with zero greenhouse emissions. Also, solar energy replaces fossil fuels thereby reducing the amount of emissions generated by such fuels (Department of Energy par.3). The burning of fossil fuels such as diesel and natural gas in vehicles and thermal power plants leads to emission of gases such as carbon dioxide, carbon monoxide, methane, and nitrogen oxides among others. These gases accumulate in the atmosphere and make the air toxic. Also, the gases form a blanket around the earth which trap the reflected radiation from the earth and prevent it from leaving the atmosphere, a phenomenon known as the greenhouse effect. The greenhouse gases leads to the rise of global temperatures which is feared to have detrimental effects on the environment such as changing of weather patterns and melting of polar ice. The proliferation of solar energy can alleviate pollution and global warming caused by the greenhouse gases.
Solar is beneficial to the economy because it created jobs for people working in the solar industry. Since 2013, solar energy jobs have increased by about 22%, which is higher than the national job growth rate by a factor of ten. Currently, there are about 175,000 workers working in the solar industry in the United States (Department of Energy par.4). Also, in the last twelve months, one of every new 78 jobs created in North America was in the solar industry.
Conclusion
Solar is a renewable form of energy as energy from the sun is inexhaustible. Photovoltaic solar panels are used to harvest the electromagnetic radiation from the sun. In earlier years, uptake of solar energy was limited due to the high prices and low efficiency of solar panels. However, the prices of solar panels have fallen drastically in recent years. Also, the efficiency of solar panels is continuously improving. As a result, the solar industry is expected to experience increased growth in the next few years.
Works Cited
“Solar” Institute for Energy Research. n.p., n.d. Web. 8 February 2016.
“Solar Energy in the United States.” Department of Energy. Department of Energy, n.d. Web. 8 February 2016.
“Solar Industry Breaks 20 GW Barrier - Grows 34% Over 2013” Solar Energy Industry Association. n.p., n.d. Web. 8 February 2016.
