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50Таким образом, в данной статье были рассмотрены одни из главных блоков оперативной коммутации тока для системы электропитания ИТЭР.
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APPLYING PHOTOVOLTAIC SYSTEMS: ADVANTAGES AND DISADVANTAGES Sheraliev D.D.
Sheraliev Davronbek Dilshodjohn o 'g 'li - Student, POWER ENGINEERING FACULTY, ELECTRIC ENGINEERING DEPARTMENT, FERGHANA POLYTECHNIC INSTITUTE, FERGHANA, UZBEKISTAN
Abstract: the article under discussion describes applying photovoltaic systems in generating electricity and reveals their advantages and disadvantages. The author of the article discusses the main features of photovoltaic systems among which are relatively long lifetimes, absence of pollution and greenhouse gas emissions.
Keywords: photovoltaics, systems, scale, applications, pollution, greenhouse, manufacturing, increase, reliability, solar, efficiency, protection, pipelines, environment.
Photovoltaics (PV) is the conversion of light into electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry. Photovoltaic systems have long been used in specialized applications, and stand-alone and grid-connected PV systems have been in use since the 1990s. They were first mass-produced in 2000, when German environmentalists and the Eurosolarorganization got government funding for a ten thousand roof program. Advances in technology and increased manufacturing scale have in any case reduced the cost, increased the reliability, and increased the efficiency of photovoltaic installations. Net metering and financial incentives, such as preferential feed-in tariffs for solar-generated electricity, have supported solar PV installations in many countries. More than 100 countries now use solar PV [1, p.p.167-174].
Overall the manufacturing process of creating solar photovoltaics is simple in that it does not require the culmination of many complex or moving parts. Because of the solid state nature of PV systems they often have relatively long lifetimes, anywhere from 10 to 30 years. To increase electrical output of a PV system, the manufacturer must simply add more photovoltaic components and because of this economies of scale are important for manufacturers as costs decrease with increasing output.
Solar PV has specific advantages as an energy source: once installed, its operation generates no pollution and no greenhouse gas emissions, it shows simple scalability in respect of power needs and silicon has large availability in the Earth's crust.
PV systems have the major disadvantage that the power output works best with direct sunlight, so about 10-25% is lost if a tracking system is not used. Dust, clouds, and other obstructions in the atmosphere also diminish the power output. Another important issue is the concentration of the production in the hours corresponding to main insolation, which do not usually match the peaks in demand in human activity cycles. Unless current societal patterns
of consumption and electrical networks adjust to this scenario, electricity still needs to be stored for later use or made up by other power sources, usually hydrocarbons [2, p.p.5-25].
While solar photovoltaic (PV) cells are promising for clean energy production, their deployment is hindered by production costs, material availability, and toxicity. Data required to investigate their impact are sometimes affected by a rather large amount of uncertainty. The values of human labor and water consumption, for example, are not precisely assessed due to the lack of systematic and accurate analyses in the scientific literature.
The 122 PW of sunlight reaching the Earth's surface is plentiful—almost 10,000 times more than the 13 TW equivalent of average power consumed by humans. This abundance leads to the suggestion that it will not be long before solar energy will become the world's primary energy source. Additionally, solar electric generation has the highest power density (global mean of 170 W/m2) among renewable energies.
PV installations can operate for 100 years or even more with little maintenance or intervention after their initial set-up, so after the initial capital cost of building any solar power plant, operating costs are extremely low compared to existing power technologies.
After hydro and wind powers, PV is the third renewable energy source in terms of global capacity. At the end of 2016, worldwide installed PV capacity increased to more than 300 gigawatts (GW), covering approximately two percent of global electricity demand. China, followed by Japan and the United States, is the fastest growing market, while Germany remains the world's largest producer, with solar PV providing seven percent of annual domestic electricity consumption.
Solar power is pollution-free during use, which enables it to cut down on pollution when it is substituted for other energy sources. Compared to fossil and nuclear energy sources, very little research money has been invested in the development of solar cells, so there is considerable room for improvement. Nevertheless, experimental high efficiency solar cells already have efficiencies of over 40% in case of concentrating photovoltaic cells and efficiencies are rapidly rising while mass-production costs are rapidly falling.
Photovoltaic power is also generated during a time of day that is close to peak demand (precedes it) in electricity systems with high use of air conditioning. Since large-scale PV operation requires back-up in the form of spinning reserves, its marginal cost of generation in the middle of the day is typically lowest, but not zero, when PV is generating electricity [3, p.p.148-173].
Solar cells produce direct current electricity from sunlight which can be used to power equipment or to recharge a battery. The first practical application of photovoltaics was to power orbiting satellites and other spacecraft, but today the majority of photovoltaic modules are used for grid connected power generation. In this case an inverter is required to convert the DC to AC. There is a smaller market for off-grid power for remote dwellings, boats, recreational vehicles, electric cars, roadside emergency telephones, remote sensing, and cathodic protection of pipelines.
References
1. Lo Piano, Samuele; Mayumi, Kozo. «Toward an integrated assessment of the performance of photovoltaic power stations for electricity generation». Applied Energy. 186(2). P.p. 167-174.
2. Bushong, Steven. «Advantages and disadvantages of a solar tracker system». Solar Power World, 2016. P.p. 5-25.
3. Jacobson Mark Z. (2009). «Review of Solutions to Global Warming, Air Pollution, and Energy Security». Energy & Environmental Science. 2 (2). P.p. 148-173.
