Can thin film really beat crystalline silicon technology?


Last week MNRE has released the generation data of solar projects operating under NVVN and it is clearly visible that the energy yield from the projects which has used thin film technology is about 10-15% higher as compared projects of crystalline silicon technologies. Picture1Adoption of thin film technologies for utility scale plants started in the NVVN projects as the thin film modules imported while a project which has to use crystalline silicon module it has to be resourced purely from the domestic suppliers as part of NVVN guidelines. Most of the NVVN projects adopted first solar modules and there was lot of criticism about thin film technology and now when the generation figures from thin film technologies are better it gives comfort to project developers in selecting thin film technology. Recently Mahindra EPC has signed an MOU with First solar and most of their upcoming plants will be using first solar modules.

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Increased efficiency and cheaper material are the two factors, which have made thin film technology price competitive has compared to traditional crystalline silicon technologies. The cost of thin film modules is still about 10% higher as compared to crystalline silicon modules but we believe that in future the price reduction potential is huge in thin film technologies. Recently first solar announced that there modules at 36 cents per Watt by 2017.

Recently IBM has introduced solar cells which are made from copper based material and has the advantage that the cells can be meet typical inexpensive ink based process. The thin film technology has in major categories which comprise of CIGS (Cadmium indium gallium selenide) and CdTe technology .While CdTe technology is by first solar in market the CIGS technology is led by solar frontier from japan. Efficiency in these modules have reached about 12-13%. Which has made crystalline silicon technologies vulnerable in terms of their existence and survival in price war

thin-film-depositionHIT MODULE

Another advantage of thin film technology is their temp coefficient which is about -0.2%/⁰C as compared to typical crystalline of-0.5%/⁰C.This makes thin film attractive and sustainable to operate in high ambient Indian temperature conditions. Typically thin film modules are frameless and semiconductor material is sandwiched between glass which leads to lower cost and light weight. The lower temperature coefficient of thin film modules makes it easier in terms of inverter compatibility and string size can be designed in a such a way that the output voltage remain within the range of inverter input window.

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As thin film module are frameless it requires special clips and structures so that the mechanical stress-thermal stress on the structure do not cause module breakages. The DC wiring in case of thin film module will require more number of circuit combiner Box as compared to typical crystalline silicon modules. Overall if we are selecting thin film modules we have to consider about 20% more space for a given project size as compared to crystalline silicon modules.

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It is expected that considering the fact that crystalline silicon modules manufactures do not have any further scope for price reduction and recent price fall of crystalline silicon was because of oversupply. It is expected that thin film technologies may lead the market in future. Some of the companies such as SANYO as come up with a technology which is hybrid of crystalline silicon and thin film technology known as Herto junction features and technologies which combine the features of crystalline and thin film will absorb wider spectrum of solar radiation. As highlighted by first solar if we get PV modules at 36 cents/W solar PV will surely reach to grid parity and the growth of the sector will be not be constrained by the policies.

by,

Dr Sanjay Vashishtha & Rishikesh Muthyal

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2 responses to “Can thin film really beat crystalline silicon technology?

  1. The data refered here only compares CUF, not weather adjusted PR which is an international way of coparing plants. CUF doesn’t account for the inputs (what radiation and weather availlable at one site and what is at other) so if a site which doesnt have eneough radiation will obviously have low CUF irrespectiveof technolgy.
    Further there is no clarity for a 5MW ac plant what is the DC capacity used? if some plant has AC/DC ratio of 1.1 and other have 1.15 or 1.2, it is not right comparision! There are no of variables in a system other than modules which can change total system performance…are this analyis has a mechanism to keep them at par and then conclude…

    so repeat agin “there is more detailed investigation required with quality of data before any proper conclusions”.

    Best way to compare the technogies is to have all technolgy to be placed in one environment, having same system design and data measured for long period in detail and then see comparision.. like done by Photon etc.

    • It is fact that mono crystalline solar panels are having higher efficiency as compared to typical thin film panels. Also the fact that historically market uses predominately mono crystalline solar cells which has history of installation over 25 years. However the article talks about the recent trends in solar PV installation specially under NVVN program me which had a local content requirement in case the project developer want to use mono/poly crystalline technology. that is the reason due to cost aspect project developer adopted thin film panels. the article also highlights the recent data of actual generation where in thin film performing better in terms of overall power output (PLF). WE agree to the fact the PLF is not the right comparison because it does not take weather parameters, hence PR is a better benchmark to compare different projects.

      the article only says about that in future cost reduction potential is higher in case of Thin film technology has they have lower level of embodied energy. The material used for manufacturing of Thin film is also cheaper, which paves the bay for module cost reduction in future. Our argument for module cost reduction is based on the recent announcement of First solar, which says that the solar panel from first solar will be available 36c/w by 2016. we agree to the fact that thin film technologies cannot beat crystalline solar technologies in terms of module efficiency in near future however the emphasis of the article is not on the efficiency, the article predominately focuses on market penetration potential of thin film vs mono crystalline . we still believe if company like first solar achieves 36c/w . it will be difficult for crystalline tech manufactures to compete in price terms.

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