Building a Power Station for Solar Energy - Article Example

Building a Power Station for Solar Energy ID: Declaration I declare that all information given in this paper is for research purposes only and Data has been collected from various sources as mentioned in the attached reference list. Abstract As development of technology to generate clean electricity from non-conventional alternative energy resources is gathering rapid momentum across the globe, electricity from solar power has emerged as a good and viable alternative to thermal power. While photovoltaic (PV) and solar thermal power are the two types of solar power generation processes, photovoltaic based solar power generation is being considered the better alternative. The cost of electricity generated by using PV solar panels has witnessed substantial decrease from 1950s. Technological development and continuous research efforts to find cheaper and more viable source materials for PV cells has been one of the major factors responsible for this decrease. This paper discusses about the process involved in generating electricity through arrays of PV cells, as well as the use of thermal technology to utilize solar energy for electricity generation. As there are different types of PV cells used in solar power generation process, a discussion on these follows next along with the description of available types of solar power plants. The discussion on design involved in building these two different solar power stations follows this. Discussion on cost and parameters affecting the prices of PV cells and other components comes next. Detailed discussion on the global solar power capacities generated during last 5 to 10 years follows the above, while highlighting the increasing global trend to generate electricity form solar energy. The attached annexure 1 & 2 display diagrams and tables concerning various topics and subtopics as discussed in the main paper. Key words: Solar power, Photovoltaic cells, power panels, solar thermal power, electricity generation Table of Contents Introduction………………………………………………………Page 4 Solar power generation process………………………………....Page 4 Working of PV panels and solar cells………………………….. Page 5 Types of solar power plants…... ……………………………..... Page 6 Photovoltaic solar power plant…………………………… Page 7 Solar plant generating thermal power……………………... Page 7 Concentrating solar power plant……………………………Page 8 Types of photovoltaic panels to generate solar power…………..Page 8 Wafer photovoltaic panels………………………………….Page 8 Thin film photovoltaic panels………………………………Page 8 Building a solar energy power station…………………………... Page 9 Steps to build a photovoltaic solar power station………… Page 10 Solar thermal power plant………………………………… Page 10 Solar power cost…………………………………………………... Page 11 Increasing trend in solar power generation …………………….. Page 13 World’s largest PV solar power plants…………………………... Page 15 List of tables (Annexure -2) Table #1: Solar technologies at a glance Table #2: Evolution of global annual installations, 2000 t0 2013 Table #3: Evolution of global cumulative installed capacity 2000 to 2013 (MW) Table #4: Net power generation capacities Table #5: Ten largest PV solar power plants List of figure (Annexure-1) Figure #1: Solar generation scheme Figure #2: PV panels Figure #3: Solar panels Figure #4: Solar power station Figure #5: Solar thermal power plant Figure #6: Photovoltaic solar resources in USA Introduction The global concerns, about increasing environmental pollution and green house effect, have resulted in active search for clean and green alternative energy resources. As thermal power plants are mostly responsible for maximum exhaust of carbon dioxide into the atmosphere, across the world, solar power provides an economically viable solution to generate clean electricity. Accordingly, solar power generation is picking up rapidly as countries all over the world realize the importance of generating financially feasible power from solar energy. Building of large capacity solar power plants across Europe, Asia and America, during the last 5 to 10 years, indicates the seriousness to combat the air pollution hazards, globally. The use of a solar power plant in an active manner involves direct conversion of sun’s energy into electricity that can normally run household appliances such as lighting bulbs, fans, water coolers and other gadgets. However, this type of power generation requires the construction of buildings and houses in such a manner, which will ensure their maximum exposure to sunlight. Solar power generation process Figure-1 in the annexure-1 displays a simple process of generating electricity from solar energy. The use of photovoltaic cells involves arranging them in a grid, called a PV panel. This panel is made from silicon-based material, which is covered by two electrical contacts on both sides. Accordingly, these panels capture the solar energy between the two electric points. However, capturing more energy requires maximum exposure of panels to the direct sunlight. Hence, a south facing roof with proper slope is ideal for this process. The cover glass serves as a protection for the semiconductor silicon PV cell against wind and other natural elements. The antireflective coating provided on this material ensures complete absorption of sunlight without dithering it away is different directions. The absorbed sunlight frees the electrons from atoms of the semiconductor. As semiconductor has a positive and negative charge at two sides, the electrons flow in one direction. This generates an electric current. The front and back contacts capture this electric current to form an electric circuit, as shown in the figure. However, the current thus generated is the ‘Direct Current’ (DC) and it needs conversion into ‘Alternating Current’ (AC) before using in the houses and offices. Hence, an inverter is part of the generating unit, which converts DC into AC. As displayed in the figure, the building fuse box receives the inverted AC electricity for onward transmission to the household items, which can run on this power. There is a metering box meant to keep a track on the amount of power that the PV panels are generating by using solar energy. This also helps the owner in receiving any subsidy payments that are applicable for installing solar power plants. In addition, owners can look for getting a bonus payment towards the units, which are generated but not consumed. The units thus saved are passed to the power grid that is responsible for supplying electricity to the region.(How Electricity, nd) Working of PV panels and solar cells As shown in the figure-3 of appendix-1 attached to this paper, solar cells are various silicon cells that are housed in a solar power panel. These cells in the power panel absorb the solar energy, while the panel ensures the generation of electricity from the solar energy. The generation process applies the photovoltaic effect for converting solar power into electricity through these power panels. Hence, they remain one of the significant components of any solar power generating plant. It is essential to install these panels on a clean surface, at a place that has the maximum exposure to sunrays, throughout the day and during all seasons of the year. The solar power panels are not expensive and these panels do not require any major expense towards maintenance. However, installation and starting charges must be taken into account when preparing financial feasibility report for building a solar power plant. The saving in electricity charges by using solar power can very well compensate the initial cost of installing these power panels. The photovoltaic cells that are part of the solar power panels ensure the conversion of solar energy into DC electric power. As each solar cell can generate certain amount of power, the cell shown in the figure is able to generate 0.5 V of electric power. There are normally 36 solar cells in a power panel and one 12V panel is ale to generate around 170V of electric power through these 36 cells. There is likelihood of voltage reduction during the charging of solar power panel. The demand for the electric power being high, it is always economically feasible to install huge number of these panels, required for getting the higher power output. In addition, the high voltage output also means less wiring from the power panels to batteries, for transferring the electricity generated by the system. Batteries are responsible to tore the DC power.(How Solar, nd) Types of Solar power plants The following paragraphs give details about three different types of power generating plants, being constructed currently around the globe. Photovoltaic solar power plant In this type of solar power plant, the photovoltaic cells are responsible for capturing the energy received from sunrays and subsequently converting this energy into electric power. As this conversion process does not involve use of any chemicals or carbon-based product, the electricity generated through this power plant is clean and free from any pollutants. In addition, installing grids comprising of photovoltaic cells in the premises of a building ensures maximum possible energy output, required to run the household electrical devices in the building. Solar plant generating thermal power The requirement of many European countries to consume large quantities of hot water, especially during winter months, has necessitated the need for finding innovative methods of generating thermal power that can heat the water in boilers, without causing any pollution to atmosphere through injurious exhaust fumes. Accordingly, solar thermal energy generating plants use solar heaters to heat water that find use in any household to run the heating system, while heating water in the boilers. Thermal cells, installed for this purpose, are responsible for capturing the solar energy and then converting it into thermal energy. The heat generated by this process finds use in discharging many household chores such as drying clothes or cooking. In addition, this energy can be used to heat water in the swimming pools as well as for bathing purposes. The heating system inside the homes and commercial buildings would require medium temperature setting as they make use of this solar thermal energy. Heat energy output at high temperatures, from this process plant, is useful for generating electricity that can run other daily-use household devices in offices and homes. Figure-2 in the enclosed annexure-1 displays an image of a building with solar thermal cells. Concentrating solar power plant This power generating plant has lenses and mirrors installed in addition to the photovoltaic cells, which help in capturing maximum energy from sun. These mirrors direct the sunlight towards the photovoltaic cells, as they convert the energy from sunrays into heat energy. As the solar energy concentration increases with the use of specific lenses and mirrors, they help in getting maximum possible sunlight. However, they involve huge financial commitments for installation and maintenance of these mirrors. Hence, only big commercial enterprises go for this type of solar power generating plant (Types, nd) Types of photovoltaic panels to generate solar power As photovoltaic cells mainly use of semi-conducting material, silicon, for solar power generation, some other materials such as copper indium, gallium, selenide and cadmium telluride are also used in these panels. However, there are different types of PV cells as described below. Wafer Photovoltaic panels The process of making wafer photovoltaic starts with cutting wafer slices from silicon-based ingots. The wafers are then connected electrically with each other. The wafers thus connected are packaged to form a module, while these modules are further joined together to form an array. Currently, the conversion efficiency of these modules, for getting electricity from solar energy, is around 20 percent. However, with improvement in the process, the conversion rate will increase in the coming years. Thin film photovoltaic panels This technology involves use of very thin layers of silicon semiconductor material, with thickness in microns, for making the PV cells. The advantage of thin film cells includes their ability to absorb more solar energy. However, they require more space to produce the specified amount of electricity than the traditional PV cells. In addition, thin film PV cells are less efficient in converting solar power into electricity, as they can convert 6 to 11 percent of solar energy against the wafer PV cells, which can convert 15 to 20 percent of solar energy into electricity.(Solar power, nd) The figure-6 given in the attached annexure-1 shows the map of photovoltaic solar resources across USA. The map gives the yearly average of solar radiation available in different zones for absorption by photovoltaic cells, as they are tilted towards sunlight for getting the maximum solar rays. While the photovoltaic cells described above are currently used for solar power generation, research studies are continuing for development of low cost photovoltaic cells, using new materials that could result in improvement in conversion efficiency. These research efforts include making PV cells from non-earth materials such as organic solar cells that can replace use of rare earth materials such as gallium, tellurium and indium. At present, thin film PV modules require these materials. The wide use of mirrors and lenses along with new improved PV cells can also increase the absorption rate of solar rays by them. In addition, carbon nano-tubes can prove to be a better alternative for the PV cells, as latest nano-technologies find their application in solar power generation. Efforts are continuing in finding low cost solutions to solar power generating processes through bioengineering and other improvements in the manufacturing process.(Solar power, nd) Building a solar energy power station Electricity from sunlight can be produced by utilizing two different processes, namely photovoltaic electricity and solar thermal electricity. Steps to build a photovoltaic solar power station The figure-4 in attached annexure-1 displays the working of solar power plant as sunlight is converted into electricity for consumption in homes, using photovoltaic cells. The steps involved in the power generation of such a solar power plant are detailed briefly below: The arrays of solar panels receive light directly from sun. The next step involves generation of electricity through the PV panels. This process is described in detail in the preceding paragraphs. The direct current received in this manner is transferred to alternating current, for which an inverter is installed near the system. As there is a need to transmit this electricity, over a distance, for reaching the desired building, a proper transmission cabling system is erected for this purpose, as shown in the figure. However, often the generated electricity is transmitted via the local cables. The transmission lines have the required transformers for transmitting the electricity in a safe manner. Once, the generated electricity reaches the desired destination, the transformers boost the voltage to ensure that it matches the required voltage and current specifications. Thereafter, the local transmission lines carry this electricity for distribution to homes and offices through the specified electric utilities. Solar thermal power plant The complete production process chart of this power plant is given in the figure-5 of attached annexure-1. The first step includes installation of solar collectors, which collect the energy directly from sun. Next step involves utilization of this energy for heating the synthetic oil, which is also called therminol. It is essential to erect piping on the solar collectors for heating this oil as it passes through these pipes. Next step involves the installation of a solar super heater, which utilizes the heat of hot synthetic oil as pipes containing it pass through the water stored in the super-heater. The process results in creation of steam from the heated water of super-heater. In addition, a supplementary natural gas boiler is also installed for heating the water during cloudy days, which is done through the burning process of natural gas. Next step involves erection of a turbine meant for generating electricity, as the piped steam as well as natural gas, thus formed, goes to the turbine. A cooling tower built on site serves the purpose of providing cooling water circulation through a condenser. The turbine runs the generator for producing electricity, while electric power thus generated goes to the transformer to change the electric voltage as per the requirement of transmission lines. Another voltage booster may be required at the receiver’s end before this electricity goes to the consuming households through local transmission lines. (Solar, nd) Solar power cost While the trend for harnessing solar energy to generate electricity is increasing with each passing year, solar power generated amounted to 0.5 percent of the total electricity generation across the world, in the year 2011. This was 0.2 percent of the total electricity generated in USA, during the same year. The total power generated through solar energy usage increased at the rate of 40 percent from 1,5 GW in the year 2000 to 69.8 GW in 2011, across the world. This indicates the fast growth of solar power generation during the last decade, while the trend is continuing at a fast pace. One of the main reasons for this fast growth is the declining cost for installation and maintenance of solar power plants. According to available facts, the costs for installing solar photovoltaic-based power plants along with the cost towards required equipment and building the electric grid connection declined from $7.5 per Watt in 2009 to $4.44 per watt in the year 2012. This cost reduction was most apparent in the year 2011, with 17.4 percent drop. The factors responsible for cost declines include, increased scale efficiency, vertical integration of the production process and higher production of polysillicon, which is the main material for making PV modules. The drop in cost of solar power is visible when considering the fact that $300 per watt was the initial cost when solar power electricity generation started production in 1950. In contrast, the solar thermal power also called, concentrating solar power (CSP) cost decline could not keep pace with drop in cost of power production through PV cells. This has resulted in conversion of CSP plants to PV technology from the year 2011. Setting of projects such as Tessera Solar and Solar Millennium is an example in this direction. While the CSP plants accounted for almost eight times to PV modules solar plants in 2008, the trend changed slowly during the following years. The generation capacity for PV solar was 1.6 times that of CSP in 2011. While the cost of production may be higher for CSP, it has certain advantages such as its capability to integrate with fossil fuel driven conventional turbines and the capability of CSP to store more power. As PV modules amount to almost half of the total cost of the complete system, the improvement in other components of the system can present an opportunity towards further cost decline in coming years. However, many challenges remain, concerning the solar power generation in coming years. These include achieving cost reduction towards installation of the solar panels and reduction in cost of non-panel equipment. In addition, the power storage issues along with grid integration problems are posing challenges to the expansion of solar power plants in near future.(Solar power, nd) Although solar power is deemed expensive when compared to conventional power, there are indications that it might become cheaper in many regions of the world, especially where there is abundance of sunlight. The falling prices of silicon and government subsidies available in most of the countries would result in further drop in solar power cost. The forecasted assumptions suggest that solar power share in electricity consumption will be around 14 percent in US alone, while gaining substantially in other countries. This would translate into less air pollution as carbon dioxide emissions will reduce drastically, when people opt for solar energy generated electricity. (Solar power, nd) Table #1 given in Annexure-2 shows the data related to cost and capacity installation for solar power plants, as of early 2012. Increasing trend in solar power generation The year 2013 witnessed an addition of almost 37.007 megawatts of solar power across the globe taking the total installed capacity utilization to 136,697 megawatts, which meant an increase of around 35 percent during the year. With initiation of processes to generate solar power, Europe had dominated the scenario for almost one decade until 2013. However, China vigorously started installing photovoltaic-based solar power stations during the last couple of years. Chart #2 in the attached appendix-2 displays the yearly data of global solar power capacity generation from the year 2000 to 2013. The chart clearly shows the dominance of solar power generation by Europe and America until 2012-13 and thereafter China took over with heavy capacity installations across the country. Chart #3 in the appendix-2 displays the data related to accumulated global solar power installed capacities across the world, from the year 2000 to 2013. The dominance of Europe can be seen in this chart as it contributed to over 70 percent of global solar power installation in 2011, while it still dominated the scenario with around 59 percent contribution in the following two years. However, even with the addition of new installation of 10 GW solar power capacity, the European continent held only 28 percent of total worldwide installations during 2013. As is evident from the chart # 4 given in appendix-2, Europe has been keen in using non-conventional energy resources to generate power and PV-based solar power is the second largest utilization of such resources, in terms of capacity generation, while wind power takes a narrow lead over the solar power. Electricity demand in Europe being higher during the day, solar power from PV panels comes handy due to the abundance of sunlight at that time. Accordingly, solar power contribution in Europe during the peak time is almost 6 percent while it is 3 percent of the total power consumption. However, there is evidence of slow down in solar power generation and utilization since 2012-13. Many reasons are responsible for this, while austerity measures taken by many European countries pose the major challenge to solar power capacity expansion. According to EPIA sources, the slowdown has also resulted in loosing the confidence of investors for putting up new PV based solar power plants, as the demand has decreased drastically in many countries. For example, Italy experienced a decrease in market demand, up to 70 percent, for solar power, while Germany witnessed the decrease in demand to the tune of almost 57 percent, in the year 2013 as compared to the previous year. According to EPIA reports for the year 2013, China was leading in solar power generation with around 11.3 GW available to the electricity grid of the country. Japan followed China with around 6.9 GW capacity generation and USA was at the third place with capacity generation of 4.8 GW.(Shahan, 2014) World’s largest PV solar power plants As given in the table #5 of annexure-2, Ukraine is the number one with the largest installed solar power capacity of 100 MW under the name of ‘Purovo’. ‘Active Solar’ developed the plant, which was connected to the national grid in 2011. Solar power plant at Canada with the name of ‘Sarnia’ comes at number 2 with 92 MW installed capacity. Enbridge owns the plant; while ‘First Solar’ developed it. This plant was connected to the grid in 2010. Montalto di Castro is the name of the solar plant, installed in Italy, which comes at number three. Built by ‘sunpower’ this plant has the capacity of 84 MW. The plant was connected to grid in the year 2011. Germany has a solar power plant under the name of ‘Finstrwalde’, with 83 MW capacity, which is the fourth largest solar power plant in the world. Developed and owned by ‘Q-cells’, this plant was connected to grid in 2010. Ukraine has another solar plant that is the fifth largest in the world, by the name of ‘Ohotnikovo’, developed and owned by ‘Active solar’ with capacity of 80 MW. It was connected to grid in 2011. Senftenberg II & III is another solar power plant in Germany that comes at number six with 78 MW installed capacity, developed by ‘Saferay’. This plant was connected to grid in 2011. Lieberose is yet another German solar power plant, developed by ‘Juwi solar’, with a capacity of 71 MW, which comes at number seven. This pant was connected to grid during 2009 to 2011. Solar plant under the name of ‘Rovigo’ in Italy comes at number eight, with 70 MW installed capacity, developed by ‘SunEdison’ and owned by ‘First Reserve’. This plant was connected to grid in 2011. Olmedila de Alarcon is the Spanish solar power plant that comes at number nine, with the installed capacity of 60 MW, developed and owned by ‘Nobesol Levante’. The plant was connected to grid in 2008. The tenth largest solar power plant has the name as ‘Boulder City (Copper Mountain)’. ‘First Solar’ developed this plant with the installed capacity of 55 MW, while ‘Sempra Generation’ owns it. The plant was connected to grid in 2010. (Top 10, nd) Conclusion Generation of electricity from solar energy is bound to be the theme of power production for the next couple of decades. While projects involving solar power plants have come up during last 5 to 10 years in Europe and America, there is a need for setting up these plants in other regions such as Asia and Africa, where abundant sunlight is available. Tropical regions of Australia can tap solar energy efficiently. Building of solar power station will become easier and simpler in coming years, due to continuing efforts to develop cheap sources of PV material that can replace or supplement silicon. Works-Cited (References) How electricity is generated through solar power , (nd), edf energy Retrieved May 05, 2015, from https://www.edfenergy.com/energyfuture/solar-generation How Solar Power Panels Work, (nd). Conserve energy future, Retrieved April 25, 2015, from http://www.conserve-energy-future.com/HowSolarPowerPanelsWork.php Shahan. Z, (2014) World Solar Power capacity Increased 35 % in 2013, cleantechnica.com, Retrieved April 25, 2015, from: http://cleantechnica.com/2014/04/13/world-solar-power-capacity-increased-35-2013-charts/ Solar- How Solar Plants Work, (nd), Next Era Generation Resorces, Retrieved April 25, 2015, from: http://www.nexteraenergyresources.com/what/solar_works.shtml Solar Power-Quick Facts, (nd),. 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