The utilization of solar energy as an alternative energy to overcome crisis energy, especially oil, happened since 1970s get a quite big attention from various countries all over the world.
Why Solar Power?
The advantages of solar energy include
- its nonpolluting nature;
- it is nondepletable,
- reliable, and
- free fuel.
The disadvantages of solar energy are that
- the solar energy concentration is very dilute, so collectors with large surface area are needed.
- In addition, solar radiation is neither constant nor continuous for terrestrial applications (i.e., low capacity factor).
- The solar energy received depends on latitude, season, time-of-day, and atmospheric conditions.
How it works ?
There are three processes for converting solar energy
- heliochemical: the photosynthesis process
- heliothermal: heating of a secondary fluid (solar thermal)
- helioelectrical: photovoltaics (solar cells)
There are three general categories of solar-energy collection systems:
- direct conversion of sun rays to electricity with solar cells (photovoltaics),
- flat-plate systems producing low-temperature (<150°F) thermal energy for heating and cooling of buildings; the thermal energy generated in the collector is usually removed by either air or an ethylene glycol-water solution, and
- concentrating solar collection systems that produce high-temperature thermal energy for the generation of electricity
Read more: SOLAR (http://holbert.faculty.asu.edu/eee463/SOLAR.HTML )
Photovoltaic Solar Power Plant:
Picture – Solar Photovoltaic Power Plant Diagram [Source: Tennessee Valley Authority (TVA)].
Photovoltaic Solar Power Plant (PLTS) consist of,
- Solar Cell Modules (DC Generators)
- Inverter and Transformer
Light or ray of solar could be converted into electricity by using solar cell technology or photovoltaic.
Solar photovoltaic (solar cell) is a direct conversion of the sun’s electromagnetic radiation to electricity, and is not limited by Carnot cycle efficiency considerations. Photovoltaic (PV) cells employ a solid-state diode structure with a large area on a silicon wafer. The surface layer is very thin and transparent so that light can reach the junction region of the silicon sandwich. In that region the photons are absorbed, releasing charges from their atomic bonds. These charges migrate to the terminals, raising the potential. A single cell has an open circuit the voltage of approximately 0.6-1.0 volts and a short circuit current of a few mA. In order to increase both current and voltage, the individual cells are placed into (solar) arrays where cells may be connected in series to raise the voltage and current output can be raised by parallel connection of cells.
The main component of Solar Power Plant (PLTS) system by using photovoltaic technology is solar cell.
Currently there are many solar cell-making technologies. The current commercial conventional solar cell uses wafer silicon crystalline technology with a quite complex and expensive production process.
Generally, the making of conventional solar cell is initiated by the process of silica purifying to produce silica solar grade (ingot), continued with the cutting of silica to be wafer silica.
Next, the wafer silica is processed becoming solar cell, and then the solar cells are managed becoming a solar module.
The last stage is integrating the solar module by BOS (Balance of System) becoming PLTS system. BOS is a supporting component used in PLTS system such as inverter, battery control system, and others.
Thermal Solar Power Plant:
Picture – Solar One Power Plant [Source: The Geo-Images Project].
Solar thermal is the use of a vapor power cycle that requires the concentration of solar energy to reach high temperatures and reasonable thermal efficiency.
Thermal Solar Power Plant consist of,
- Heliostat & Control System
- Solar Receiver (Boiler)
- Turbine (Elecricity Generator) powered by steam
Picture – Solar concentrated power plants – how it works (Source: http://www.alstom.com)
Solar thermal, energy concentration devices include parabolic mirrors and arrays of focused mirrors (heliostats). [Note that concentrating lens such as Fresnel lens have been used for solar cells.] The solar concentrator is most expensive component in a solar thermal installation representing 40-50% of total system cost. A solar thermal power station is highly capital-cost intensive.
Hybrid System (Fossil Fuel Backup)
Picture – Hybrid System (Source http://www.greenrhinoenergy.com)
Though CST plants can operate at their full rated electric power for up to 12 hours a day in clear and sunny locations, most CST plants include a fossil-fuelled backup capability that can be used to supplement the solar output during periods of low solar readiation.
This backup can either be a facility that heats up the heat transfer fluid or an additional, fossil-fuel fired steam boiler.
Power plants in California have been connected to the grid for years, and use up to 25% natural gas in order to cover sunless periods.
Video : “Concentrated solar power solutions at utility scale” (Courtesy of Alstom)
CSP (concentrated solar power) has the potential for large-scale, efficient power generation. http://www.alstom.com/power/renewables/solar-power/
References / Related Links / Read More:
- Cost of Solar Power Still Falling, Falling, Falling (http://www.triplepundit.com/2014/02/25-million-doe-funding-for-low-cost-solar-power/ )
- Kyocera builds massive solar farm, tourist destination (http://www.japantrends.com/tag/technology/ )
- SOLAR , http://holbert.faculty.asu.edu/eee463/SOLAR.HTML
- Solar power, http://www.alstom.com/power/renewables/solar-power/
- Concentrated Solar Thermal Systems , http://www.greenrhinoenergy.com/solar/technologies/cst_systems.php
Picture – Family Solar Power System
- Shandong Zhongjing Solar Energy Co., Ltd., http://zhongjing-cnsdpv.en.made-in-china.com/product-group/SqdQGKwUrmWC/Home-solar-power-supply-system-catalog-1.html