Efficiency of Solar Cells made of Silicon(Monocrystalline,Multicrystalline) ,Thin Film (CIGS,CIS,aSi,CdTe,CZTS),Multijunction
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April 17, 2011A lot of confusion exists about solar cells efficiency about which technology results in how much efficiency and the difference between solar cells and the solar panels efficiency.Note the biggest differentiator of a solar cell besides its cost is its efficiency.Not only do different materials give different efficiencies,even different companies have conversion efficiencies which differ for the same technology.Silicon Solar Cell Efficiency also depends on the purity of the solar wafer which is used as raw material to print solar cells besides whether it is monocrystalline or multicrystalline solar cells.With most of the low lying fruit already gathered in respect to lowering cost of the silicon solar cells,most of the big Chinese solar companies are concentrating their efforts in improving the efficiency in order to cut down costs in the cutthroat solar industry where the stars of yesterday are fighting to stay alive (Energy Conversion Devices,Evergreen Solar).This rising tide of the solar industry in 2010 has not been able to revive the fortune of some companies though European companies have made enough to fight another day.Solar Cells Efficiencies also differ in the champion cells tested in labs like NREL and on commercial lines.But here is a general range of efficiency of different types of solar cells made from different technologies
SILICON
Solar Cells are of 2 types a) Multicrystalline b) Monocrysalline.Mutli Solar Cells have lower efficiency that the Solar Cells made from monocrystalline Solar Cells.
Monocrystalline Solar Cells
Solar Cells Efficiency can vary from 18% to 24% for the normal monocrystalline silicon technology.Note solar cell manufacturers are constantly improving efficiency in order to lower their costs and get ahead in this competitive solar industry.Sunpower makes the highest efficiency crystalline solar cells on a commercial scale.Sanyo is the other company which makes the most efficient Monocrystalline cells .Suniva is challenging the two with a low cost process for making high efficiency monocrystalline solar cells.
Multicrystalline Solar Cells
Multicrystalline Solar Cells have lower efficiency and costs than monocrystalline solar cells.However they are currently the more popular though that is changing.They have an efficiency in the range of 14-17%.Some companies like JA Solar are progressing to improving the efficiency of multicrystalline solar cells to reach monocrystalline solar cells.Note Innovalight a US startup is selling an innovative material which improves the efficiency and has tied up with a number of big Solar Cell and Panel manufacturers
THIN FILM
Thin Film Technology unlike c-Si has a number of variants.Amorphous Silicon (a-Si),Copper Indium Gallium Sulphide (CIGs) and Cadmium Tellurium (Cd-Te) are the 3 main types of Thin Film Technology.There are a number of manufacturers of all of these 3 types of Technology.CIGs Technology is said to have the most potential in improving efficiency and competing with c-Si,however Cd-Te is currently the top dog as the world’s biggest solar producer First Solar currently uses this technology.a-Si Technology is not that hot with low efficiencies however Oerlikon and Sharp are pushing ahead with developing this technology.
Amorphous Silicon Technology (a-Si)
This Thin Film Technology has the lowest average efficiency of all the solar cell technologies except immature ones like Organic Dye Cells.With most of the a-Si thin film competitors bankrupt or in a moribund state,Sharp is the only big player remaining claiming a 10% efficiency.Oerlikon has said that its new generation equipment will cuts cost to 70c/watt and improve efficiency to 10% from the current 9%.
Copper Indium Gallium Diselenide (CIGs)
This Thin Film Technology has the highest Solar Cell Efficiency and a number of established companies like TSMC,Q-Cells,Honda and startups like Miasole,Nanosolar,Solyndra are using this technology.However its production is not easy as four different materials are used.Miasole has been claiming to have achieved an efficiency of 13.8%.General range is between 11-14%.
Copper Indium Selenium (CIS)
Solar Frontier claims 11.5% efficiency for its CIS modules which are expected to go upto 14% by 2014.Note it is very closely related to the CIGs Technology differing only in the fact that it does not use Gallium.
Cadmium Tellurium (CdTe)
This technology has around 12% efficiency though GE has said that it has managed to attain 15% efficiency on commercial glass.Don’t know how much of it is true since First Solar only manages around 12% efficiency despite around 10 years of dedicated R&D.
Copper Zinc Tin Sulfure Selenium (CZTS)
It is a very new technology unlike the other thin film technologies and has a long way to go.However the USP is that it uses widely found metals unlike the exotic materials like Tellerium and Indium used in other Thin Film Technologies.IBM and Solar Frontier are developing this technology.It has efficiencies around th 9-10% range
MULTIJUNCTION
This technology uses a number of materials with some III-IV elements being used as well to capture sulight in different spectrums which results in higher conversion efficiency.There are a number of companies which have been working and claiming high efficiencies in the 40% range.Boeing’s subsidiary .Note Boeing Subsidiary had created a record a couple of years ago with a 39.2% multi junction solar cell.These cells are primarily used in spacecraft where low space requirements require the use of high efficiency cells without major cost considerations.Spectrolab has continued to improve on the efficiency of the cells reaching 41.6% in a NREL Lab Test.Some other companies are also claiming higher than 40% efficiency solar cells using concentrators on multijunction solar cells.
Summary
Solar Cell Efficiency Improvement is the best way to reduce the costs of solar power and reach grid parity in most places in the world.Solar Cell Efficiencies have improved continuously and with a number of companies and startups investing billions of dollars in research,it will keep improving.However cost considerations are an important factor as well and the technology which balances the two will win the solar energy race
3 Comments
You should revice your article because there is an important mistake in the Solar Frontier CIS title.
Operating in Japan Solar Frontier does not have the right to use Cadmium. CIS refers to Copper Indium Selenide. Or more simple to a chalcopyrite which puts it in the same family as CIGS CIGSe.
That they are not using any Gallium sounds unlikely. I would bet CIS was the start of the technolgy but that Gallium has been added since because it allows for improvements while reducing the consumption of the expensive Indium.
At 1GW installed capacity they have become the market leader in the CIGS field.
That was a typo on my part.I have corrected it ,thanks for pointing it out.
[…] about 86.8% for an infinite number of junctions, implying that more junctions increase efficiency.Efficiency of solar cells made from silicon normally varies from 15-24% Multijunction Cell […]