Solar Energy
Solar Energy
Generalities
The sun is the only star of our solar system located at its center. The earth and other planets orbit the sun. Ernergy from the sun in the form of solar radiation supports almost all life on earth via photosyntesis and drives the earth's climate and weather.
Sunligth is the main source of energy to the surface of the earth that can be harnessed via variety of natural and synthetic process. The most important is photosynthesis, used by plants to capture the energy of solar radiation and convert it to chemical form. Basically, all the forms of energy in the world as we know it are solar in origin. Oil, coal, natural gas, and wood were originally produced by photysyntetic processes, followed by complex chemical reactions in eich decaying vegetation was subject to very high temperatures and pressures over a long period time. Even the energy of solar wind and tie has a solar origin, sonce they are caused by differences in termperature in various regions of earth. (Soteris A., 2014:1).
Process of convertion and usages
The energy form the sun is utilized directly in two ways. The first is the thermal route in wich devices are used to collect the sun's energy in the form of heat. this thermal energy is either used straightway for aplication such as water heating, space heating drying, etc.or converted into electricity through energy conversion cycles.
Figure 1. Long-term solar energy storage
Photovoltaic (PV) devices generate electricity directly from sunlight via an electronic process that occurs naturally in certain types of material, called semiconductors. Electrons in these materials are freed by solar energy and can be induced to travel through an electrical circuit, powering electrical devices or sending electricity to the grid.
PV devices can be used to power anything from small electronics such as calculators and road signs up to homes and large commercial businesses.
Figure 2. Photovoltaic decives.
Advantages
The greatest advantage of solar energy compare with other forms of energy is that it is clean and can be supplied without enviromental pollution.Also, solar energy is a very large, inexhaustible source of energy.
The power from the sun intercepted by the earth is approximetaly 1.8*10^11 MW (Sukhatme J., 2018), wich is many thousands of time larger than the present comsuption rate on the earth of all commercial energy sources. In principle, solar energy could supply all the present and future energy needs of the world on a continuing basis, thus making it one of the most promising of the unconventional energy sources.
In addtion to its size, solar energy has two factor in its favour. First unlike fossil fuels and nuclear power, it is an enviromentally clean source of energy. Second, it is free and avaible in adequate quantities in almost all habitable parts of the world.
Disvantages
Therea a many problems associated with the use of solar enrgy. The main problem is that it is a dilute source of energy. Even in the hottest regions on earth, the solar radiation flux available rearerly exceeds 1 Kw/m^2 and the total radiation over a day is at best about 7 KWh/m^2 (Sukhatme J, 2018). These are low values from the point of view of technological utilisation. Consequently, large collecting areas are required in may applications and these result in excessive cost.
A second problem associated with the use of solar energy is that its availability varies widely with time. The variation in availability occurs daily because of the day-night cycle and, also, seasonally because of the earth's orbit around the sun. In adittion, variations occur at a specific lcation because of the local weather conditions. Consequently, the energy collected when the sun is shining mus be stored for use during periods when it is not avaible. The need for storage also adds significantly to the costs of any system, Thus, the real challenge in utilising solar energy as an energy alternative is of an economic nature.
Current situation in Guatemala
This energy has been growing for some decades due to the logical advantage of taking advantage of the energy provided by the sun. However, it is still expensive.
Acording to IRENA in Guatemala from 2010 to 2018 the generation of solar energy goes from 0.8 GWh to almost 220 GWh increasing substantially in 2015.
As we seen in Figure 3, Figure 4 shows the same trend or turning point in the generation of electricity using solar energy as a source. This significant change corresponds to the period 2014-2015, in which a substantial increase in the generation of electrical energy from the sun could be observed. Another important aspect of this production model is that Guatemala only generates electricity from solar energy by means of photovoltaic panels. In other more developed countries, solar energy is also used for heat production, in order to reduce the consumption of electricity in heating systems and water heaters. However, the important change in the model of electricity production from renewable energy such as solar energy should not be underestimated.
The stations in operation in Guatemala are:
- SIBO Photovoltaic Solar Power Plant (effective power 5 MW)
- 50 MW Photovoltaic Plant Project (Horus I) (effective power 50 MW)
- Horus II (effective power 30 MW)
- La Avellana Solar Farm (effective power 1 MW)
- Taxisco Solar Farm (1.5 MW)
- El Jobo Solar Farm (1 MW)
- Pedro de Alvarado Solar Farm (1.5 MW)
- Buena Vista Solar Farm (1.5 MW)
Sources:
International Renewable Energy Agency. (s. f.). Renewable Energy Sources. IRENA. Consulted September 27th, 2020. https://www.irena.org/
S. P. Sukhatme & J. K. Nayak. (2018). Solar Energy (4th Edition). McGraw Hill Education. India
Soteris A. Kalogirou. (2014). Solar Energy Engineering Processes and Systems (2nd Edition). Academic Press. Oxford, England.
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