Among the of incoming solar radiation(insolation) at the upper atmosphere, earth receives about 174 petawatts (PW)of the incoming solar radiation. There are 174 Petawatts (PW) ofapproaching sunlight based radiation (insolation) at the upper environment isget by the earth. In this sum, in the scope of 30% is reflected back to spacewhile the rest is consumed by mists, seas and land masses.
At the surface ofearth, range of sun oriented light is generally spread over the noticeable andclose infrared extents with a little part in the close bright. Solar power may have had extraordinary potential,however it was left as a second thought at whatever point fossil powers weremore reasonable and accessible. “Just in the most recent couple of decadeswhen developing vitality requests, expanding ecological issues and decliningfossil fuel assets made us look to option vitality alternatives have wecentered our consideration around really misusing this colossal asset.”For example, the US Department of Energy subsidized the establishment andtesting of more than 3,000 PV frameworks amid the 1973-1974 oil ban. By thelate 1970s, vitality organizations and government offices had put resourcesinto the PV business, and “a gigantic speeding up in module advancementoccurred.” Solar vitality upgrades were again looked for amid the Gulf Warin the 1990s.1 Solar electric power can be madeeither by power plants using the sun’s heat or by photovoltaic (PV)advancement, which changes over light specifically to power utilizing by usingsolar energy.
PV development is more helpful for private usage. Structures touse the glow of the sun particularly can be either active or passive. In activestructures, air or liquid course through sun controlled experts and bringwarmth to where it is used. In passive systems, structures are worked withwindows and warmth engaging surfaces set up to extend sun based warming inwinter. Either innovation is appropriate for residential usages 1. 2.0 Solar Photovoltaic Conversion of sunlight intoelectricity is called as photovoltaic energy.
With the help of a photovoltaiccell, commonly called a solar cell or PV, the solar energy can directly convertinto electrical power. A photovoltaic cell is made up of silicon alloys whichis refer as a non-mechanical device. Sunlight has a composition of protons,or particles of solar energy. Various amounts of energy corresponding to thedifferent wavelengths of the solar spectrum is contain in the protonsfound in the sun radiant. When a photovoltaic cell is strike by theprotons, they may be reflected, pass right through, or be absorbed.
Only theprotons which absorbed the energy will generate the electricity 12.Figure1: Structure of a photovoltaic cell A photovoltaic array’s performanceis dependent upon sunlight. There will a significant effect on the amount ofsolar energy received by a photovoltaic array which might effect by the climateconditions such as clouds and fog, which in turn will affect itsperformance. Recent photovoltaic technology modules having 10% of convertingefficiency. Further research is being conducted to raise this efficiency 12.
A solar photovoltaic technology is one of therenewable technologies, which has a potential to shape a clean, reliable,scalable and affordable electricity system for the future. The earth gets astunning supply of solar energy in the future. Considering this fact, all overthe world governments are encouraging the development and deployment of solarPV technology. A wide range of PV materials are available worldwide. Globally,there are hundreds of companies involved in the manufacturing of PV moduleswith varying efficiencies and limitations. At the same time, installation costsdiffer from system to system and from project to project.
Globally there are more than 350companies from different countries involved in manufacturing of PV cells. Basedon the years of 2014’s review , the major five leading countries identified areChina, Japan, USA, Germany and UK. These five countries altogether accountedfor 80% of photovoltaic installations in 2014. The cumulative global PVcapacity has reached 177 GW by means 1% of world electricity generation is fromPV. In addition, by the end of year 2014, there are 20 countries across theglobe that has passed the benchmark of 1 GW cumulative PV installation. For theyear 2014, it has been noticed that Asia ranks in first place for the secondyear in a row with around 60% of the global PV installations 12. China, one of the biggestcontributors of Asia since decade, installed 10.
6 GW in 2014. USA has installed6.2 GW in 2014 with large-scale and new business models dominating the market.However, Europe has significantly declined from 22 GW of installation per yearin 2011 to around 7 GW in 2014.
Nevertheless, in the year 2014, PV contributes3.5% of the electricity demand in Europe and 7% of the peak electricity demand(International Energy Agency, 2015a). UK by installing 5 GW of PV projects holdsthe first position in European countries for PV installation in the year 2014,followed by Germany (1.9 GW) and France (0.9 GW) 12.Figure2. PV installations in the year 2014 for leading countries 12. From the figure, it clearly showsthat China has extremely rich solar energy resources and its PV industry isgrowing on a faster pace than any other country in the.
Such growth has beenmade possible due to the significant support of government incentives andpolicies. The Renewable Energy Law was planned in 2005by the National People Congress (NPC) and implemented in January 2006. It wasbased on five key mechanisms: (a) Nationaltarget for development of renewable energy: it directs the investment towardsall sources of renewable energies(b) Amandatory connection and purchase policy between grid companies and renewableenergy electricity generator: grid companies need to sign an agreement thatthey will purchase renewable electricity from all renewable electricity generatorsand provides the grid connection services(c) Feedin Tariff (FiT) system and price: FiT prices are fixed and will be paid torenewable electricity generators for each kWh electricity generated (d) Costsharing mechanism: the cost of grid connection and renewable energy generationwill be divided among utilities and end users of electricity by implementing asurcharge on sold electricity (e) Therenewable energy development special funds: based on this funds will beprovided to activities like research and development of renewable energy,setting up pilot projects or renewable resources assessments Japan policies are always in thefavour of the PV technology. It has constantly noticed that either thesepolicies are targeting the deployment of R on PV technology or on theclimate change issue. After the oil crisis in 1973, Japan introduced its firstPV industry support project named as Sunshine Project in 1974 which wasestablished by Ministry of Economy. In 2007, Japan’s Prime Minister launched a newscheme named as Japan’s Cool Earth Initiative (2008) with the aim of reducingthe greenhouse gases by 50% by 2050. It involves the development of latest 21technologies including solar cell technology. One of the plans under thisprogram is to develop low cost solar cell with conversion efficiency up to 40%and generate power at £0.
04/kW (7 Yen/kW) as compared to the current rate of£0.21/kW (40 yen/kW). In July 2012, another scheme called FiT was introduced which resulted more than 20.9GW of PV projects, which were approved by the end of May 2013.12 In the Middle East, Israel endured as the very first market.
While itremains to be shown that this system can be commercially viable, it shows howthe cost decline of PV systems in the past centuries has brought down PVelectricity manufacture costs.4 InEurope, the market sustained to decline, in spite of the growth of the UKmarket that recognized itself as first place in Europe with 2.4 GW in 2014.Germany experienced another market decline to 1.9 GW, with extremely reasonableenticements. France grow of Francewas close to 1 GW and the Italian market, as feed-in tariffs (FiT) marketswere phased-out, it inclined to a rather low level (424 MW).4 The solar photovoltaicadvancement is one such source that can looked upward to as boundless researchis being done and a basic change in execution has been refined.
PV is one ofthe fastest creating ventures worldwide thus as to keep up this improvementrate necessity for new advancements concerning material use and usage, gadgetoutline and generation innovations and likewise new plans to fabricate thegeneral profitability develops. A couple of PV advances, going from silicon tothin movies, multi-intersection and solar concentrator structures for terawattlevel arrangement of the current solar cells, and for every innovation,distinguished changes and developments required for further scale-up. Solar PVenergy is the answer of future energy challenges 5. 3.0 Generations of Solar PV3.
1First Generation Traditionalsolar cells are made from silicon, are currently the most efficient solar cellsavailable for residential use and account for around 80+ percent of all thesolar panels sold around the world. Solar cells of silicon bases are moreefficient and longer lasting than non-silicon based cells. However, they aremore at risk to lose some of their efficiency at higher temperatures (hot sunnydays), than thin-film solar cells. 11 Currently four types of silicon basedcells are in for residential use.
The types are based on the type of siliconused, specifically: 3.1.1Monocrystalline Silicon Cells Oneof the oldest solar cell technology which is still considered as popular with high efficiency are solar cellsmade from thin wafers of silicon. These are called monocrystalline solar cellsbecause the cells are sliced from large single crystals that have beenpainstakingly grown under carefully controlled conditions. Typically, the cellsare a few inches across, and a number of cells are laid out in a grid to createa panel. Relativeto the other types of cells, they have a higher efficiency (up to 24.
2%),meaning will obtain more electricity from a given area of panel. This is usefulif when have a limited area for mounting panels, or if want to keep theinstallation small for aesthetic reasons. However, growing large crystals ofpure silicon is a difficult and very energy-intensive process, so theproduction costs for this type of panel have historically are the highest of allthe solar panel types. Production and price for raw silicon haveimproved and panels from monocrystalline solar cells have fallen a great dealover the years, due to the competition where other types of panel have beenproduced.
Another issue arise from monocrystalline silicon cells is that theefficiency of theses panels reduce when the temperature increases about 25?C. Dueto this reason, the installation has to made is such way in order increasetheir efficiency by permit the air to circulate over and under the panels. 11 3.1.2Polycrstalline Silicon Cells Siliconwafers are cheaper to produce in molds from multiple silicon crystals ratherthan from a single crystal as the conditions for growth do not need to be as tightlycontrolled.
In this form, a number of interlocking silicon crystals growtogether. Generally speaking, polycrystalline panels have an efficiency that isabout 70% to 80% of a comparable monocrystalline solar panel. The mostefficient polycrystalline panels are built by Mitsubishi Electric Corporation.In February 2010, two world record is achieve by Mitsubishi for photoelectricconversion efficiency in polycrystalline silicon photovoltaic (PV) cells bydecreasing the resistive loss in thecells.
The conversion efficiency rates have been confirmed by the NationalInstitute of Advanced Industrial Science and Technology (AIST), in Japan. 11 3.1.3Amorphous Silicon Cells Regardlessof developing silicon precious stones is done in making the two past sorts ofsun powered cells, silicon is kept in a thin layer on to a support substrate,for example, metal, glass or even plastic.
At times a few layers of silicon,doped in somewhat unique approaches to react to various wavelengths of light,are laid over each other to enhance the effectiveness. The creation strategiesare mind boggling, however less vitality serious than crystalline boards, andcosts have been descending as boards are mass-delivered utilizing thisprocedure. Thepanels can made flexible if very thinlayers of silicon is used.
The disadvantage of amorphous panels is that theyare much less efficient per unit area (up to 10%) and are generally not suitablefor roof installations where it would require two times the area for the samepower panels. Having said that for a given power rating, they do perform betterat low light levels than crystalline panels which is worth having on a dismalwinter’s day, and when the temperature increases, it does not effect theirefficiency. However,there flexibility makes them an excellent choice for use in making buildingintegrated PV (e.g., roofing shingles), for use on curved surfaces, or evenattached to a flexible backing sheet so that they can even be rolled up andused when going camping / backpacking, or put away when they are not needed. 11 3.
1.4Hybrid Silicon Cells One recenttrend in the industry is the emergence of hybrid silicon cells and severalcompanies are now exploring ways of combining different materials to make solarcells with better efficiency, longer life, and at reduced costs. Recently,Sanyo introduced a hybrid HIT cell whereby a layer of amorphous silicon isdeposited on top of single crystal wafers.
The result is an efficient solarcell that performs well in terms of indirect light and is much less likely tolose efficiency as the temperature climbs. 3.2Second Generation Second-generation solar cells areusually called thin-film solar cells because when compared to crystallinesilicon based cells they are made from layers of semiconductor materials only afew micrometers thick. The combination of using less material and lower costmanufacturing processes allow the manufacturers of solar panels made from thistype of technology to produce and sell panels at a much lower cost. There are basically three types ofsolar cells that are considered in this category, amorphous silicon, and twothat are made from non-silicon materials namely cadmium telluride (CdTe), andcopper indium gallium diselenide (CIGS).
Together they accounted for around16.8% of the panels sold in 2009. First Solar, the number oneproducer and seller of solar panels in the world currently makes their solarcells using cadmium telluride. The big appeal of these type of solar cells isthat they are inexpensive (currently below $1.00 / watt to produce and headingtowards $0.70 / watt).
Venturecapitalists love CIGS solar cells (or at least used to – as they have investedover $2.3 billion into companies developing these cells but have yet to see thembe a commercial success) as they have been able to reach efficiency levels of20% in the laboratory. Unfortunately it has turned out to be much moredifficult to produce CIGS solar cells in mass quantities at competitive priceswith anywhere near than efficiency level, so the jury is still out on thistechnology. 113.
3Third Generation Solar Cells Currently there is a lot of solarresearch going on in what is being referred to in the industry asThird-generation solar cells. In fact according to the number of patents filed inthe United States solar research rankssecond only to research in the area of fuel cells. This new generation of solar cellsare being made from variety of new materials besides silicon, includingnanotubes, silicon wires, solar inks using conventional printing presstechnologies, organic dyes, and conductive plastics. The goal is to improve onthe solar cells already commercially available by making solar energy moreefficient over a wider band of solar energy (e.g.
, including infrared), lessexpensive so it can be used by more and more people, and to develop more anddifferent uses.Currently, most of the work on third generation solar cells isbeing done in the laboratory, and being developed by new companies and for themost part is not commercially available. 11Figure 3: Efficiency and cost projections for first- (I),second- (II), and third generation 4.0 High efficiency solar cell Tandem PV devices are the bestdeveloped so far and help change, regardless of whether by extendedconcentrator structure productivity or by diminished cost and extended adequacyof thin-film designs, can impact much lower general costs per Watt. Regardless,these devices tend to encounter the ill effects of poor spectral robustness.
Chip away at middle of the road level gadgets and up/down transformation is ata much prior stage, yet guarantees expanded efficiencies and more prominentspectral robustness, conceivably with thin-film-sort materials. The more movedthoughts of different transporter period and hot bearer cells are further awayand still have genuine hypothetical request to answer. In any case, executionof such techniques could essentially reduce cost per Watt with spectralrobustness as they are good with theoretically moderately basic thin-filmgadgets 9.
A tandem cell, by definition,comprises of no less than two p-n intersections with cells made out ofmaterials that retain diverse photon energies. The top cell would assimilatethe higher energies while the base cell would retain the lower energies thatwere not consumed by the top cell, like the guideline behind thin film cells.The couple cell would then have a higher productivity as it could retain morephotons of the sunlight based range for vitality transformation. Thisinnovation is as of now being put to use in sun oriented cells in space. Pairsun oriented cells are ordinarily made of mixes of components in the III and Vgatherings of the occasional tables.
Cases of these mixes are: gallium arsenide(GaAs), indium phosphide (InP), gallium antimonide (GaSb), gallium indiumphosphide (GaInP), and gallium indium arsenide (GaInAs). These sun poweredcells have the most elevated reported effectiveness at 43% when utilizing athree cell sun oriented cell, yet they utilize uncommon metals and areamazingly costly to manufacture, so they are not commonsense for use on farreaching earth.8 Expanded number of cells in a couple cell will build the hypotheticalmost extreme effectiveness of the solar cell, however there still remains abreaking point to the productivity. A solitary cell has a hypothetical greatestproductivity of 31%.
A two cell pair sun oriented cell has a greatestproficiency of 42.5%; a three cell sun oriented cell has a most extremeeffectiveness of 48.6%, etc. The hypothetical most extreme efficiencies willkeep on increasing, however an interminable heap of solar cells has a greatestproficiency of just 68.2%. The proficiency picked up by including another celldiminishes with each ensuing expansion.8 Considering that “the main practicalsolar cells were made under 30 years back,” there have been somesignificant progress.
The profligation of solar energy organizations outliningone of a kind and particular solar energy frameworks for individual homes,implies there is no more extended a reason not to consider the usage of solarenergy. The greatest hops in productivity came “with the appearance of thetransistor and going with semiconductor innovation.” The generation costhas tumbled to about 1/300 of what it was amid the space program of themid-century and the buy cost has gone from $200 per watt in the 1950s to aconceivable simple $1 per watt today. The productivity has expandedsignificantly to 40.8% the US Department of Energy’s National Renewable EnergyLab’s new world record as of August 2008.9 5.0 Conclusion There are a couple of centralpurposes of photovoltaic solar energy that make it “a champion among themost promising renewable energy sources on the earth. It is non-polluting, hasno moving parts that could particular, requires little support and nosupervision, and has a presence of 20-30 years with low running costs.
It isespecially remarkable in light of the fact that no large scale establishment isrequired. Remote reaches without a lot of an extend convey their own particularsupply of energy by creating as meager or as tremendous of a system as required.Solar power generators are basically scattered to homes, schools, orassociations, where their social gathering requires no extra progression orland extend and their ability is shielded and quiet. Contrast those qualitieswith those of coal, oil, gas, or nuclear power, and the choice isstraightforward.
solar energy progressions offer a spotless, inexhaustible andprivate vitality source. Wind control, hydro power as well as solar thermalpower needs maintenance and they have parts that dissemble. Therefore in thissense, solar PV has an advantage over them.
11 By enhancing the efficiency ofsolar cells, the cost of solar energy can be limited also as indicated by LarryKazmerski, Director of the DOE’s National Center for Photovoltaics. Anyimprovements and progressive cost lessening will be important to spaceapplications. Finding the privilege electrical organization likewise can helplessen the cost. They can enable you to profit with such choices. As timepasses by, the cost solar energy will keep on decreasing while the costs ofpowers keep on being on the ascent. This will at that point imply that solarenergy is going into another period of worldwide development.