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Green technology – energyBog'liq 34. FS-Green-TechnologyGreen technology – energy
It is not just efficiency alone that advocates the use of green technology in the energy sector. Reduced costs,
decreased environmental impacts, grid security and reliability are further benefits. Thus, new technologies
should be carefully integrated into the system to complement existing infrastructure.
Solar
Currently, there are two main technologies for generating electricity using solar energy: photovoltaic (PV) and
concentrated solar power (CSP). PV technology directly converts sunlight into electricity. CSP technology
collects solar thermal energy by using mirrors to reflect and concentrate sunlight to produce heat or steam and
convert it into electricity via a power generator.
PV technology can be further divided into two categories: crystalline silicon and thin-film module. Crystalline
silicon was the first PV technology to be commercialized and still accounts for most of the global production.
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Thin-film technology is generally less efficient than crystalline silicon but is also less expensive to manufacture.
Due to the low-cost advantage, thin-film technology has been adopted in emerging economies and develop
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ing countries.
The PV industry’s power plants are relatively easy to operate because the PV panels have no moving parts, thus
requiring less maintenance than CSP power plants. But due to the low conversion efficiency of the photovoltaic
cells, a large land area is needed for a high volume of electricity generation. On the plus side, the scalability of
the PV module enables rooftop-mounted applications, which represents a big potential application area as well
as a viable source for distributed electricity generation.
There are four types of CSP systems: linear concentrator, dish/engine, power tower and thermal storage. The
concept for producing electricity is basically the same for all of them. They differ in their solar concentration con
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figuration, tracking system, heat storage and efficiency. Smaller CSP systems can be used in distributed
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generation applications to produce power on-site. But unlike the PV technology, the CSP systems are not easily
scalable and are generally used in utility-scale applications. The heat generated from the CSP can be stored, so
the produced electricity does not fluctuate as widely as with the PV system, thus it possesses an advantage in
providing reliable power to utilities. Because CSP power plants commonly use steam to generate electricity and
are water cooled, the availability of water resources can pose a constriction for their application.
The high cost and low-conversion efficiency are the main barriers to the wide use of solar power systems. Costs
per unit of electricity generated from solar elements have remained relatively high in comparison to other
renewable energy sources.
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Fortunately, the manufacturing costs for the PV system decrease as the market for
the technology expands. Moreover, the current research on increasing the efficiencies of both PV and CSP tech
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nologies aims to make the generating of solar power even more cost competitive.
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