CIS PowerModules by Solar Frontier Highest yields – even under extreme conditions PowerModules www.solar-frontier.eu CIS Technology External factors for PV yields Developed for highest yields. A matter of prevailing conditions. The photovoltaic market offers a wide range but this technology is currently years away from What criteria should an ideal photovoltaic installation of solar modules based on very diverse tech- serial production. meet to consistently produce the highest yields? CISnologies. What sets CIS apart not only from crystal- The modules fall into the main categories of: line modules but also from other thin-film • Thin-film modules technologies such as cadmium-telluride is • Crystalline modules based on silicon their outstanding environmental friendliness: • Organic modules CIS PowerModules by Solar Frontier are free of • HIT and tandem solar cells cadmium and lead, requiring no special recyc- If you could select the criteria that the ideal tures, fog or clouds. And every one of these ling process. Therefore, they meet the stringent rooftop installation should have to meet, you factors reduces the yield. Thin-film technology is the most innovative requirements of the RoHS guideline (Restriction would probably choose an installation facing of these segments. But this field can be of Hazardous Substances). south on a roof tilted at an angle that is best The solution: approached in a variety of different ways. suited for sunlight to strike in any season. The Highest yields - even under One of them is the solution offered by CIS Added value throughout. environs of this installation would be absolu- extreme conditions. technology. Its name is derived from the ele- tely free of shade, the air always clear and de- ments copper (C), indium (I) and selenium (S). On the whole, the CIS technology developed void of impurities from dirt, dust, fog or smog. With CIS PowerModules by Solar by Solar Frontier offers a unique combination What‘s more, the weather would always be Frontier. Superior features. of advantageous features – not only for rooftop, both sunny and cold because in addition to but also for free-field installations: the above conditions, high solar radiation va- This is precisely where the advantages of CIS A decisive advantage of CIS over conventional lues and low temperatures offer the best pre- technology come in. Thanks to their high crystalline silicon resides in the higher output • greater efficiency & higher yields mises for the highest yields. shadadow tolerance and their favorable low- per installed watt-peak – resulting in a larger • greater security light performance the CIS PowerModules by energy production of the installation. Their • greater environmental friendliness In other words: An ideal PV installation will al- Solar Frontier offer the highest yields even advantage over other thin-film modules (such • greater aesthetics ways be rare. That‘s because the real world is under extreme conditions: with shadows, at as amorphous, micromorphous or tandem mo- usually quite different. Roofs often face east high temperatures and low light. In addition, dules) lies in the higher efficiency. Aside from Take a look at the added value of or west. Trees, chimneys or nearby buildings with what is called the light soaking effect CIS, organic modules also hold great potential; CIS PowerModules by Solar Frontier! cast shadows. Pollutants are in the air. The they even offer additional yield results. weather fluctuates between high tempera- 2 | CIS CIS | 3 Greater efficiency: excellent low-light behavior Greater efficiency: high shadow tolerance Highest yields – Highest yields – even with foggy outlook. even in the shade. Mornings, evenings, fog, diffuse light, over- Due to their high shadow tolerance, CIS thin- but the entire module shuts down. As oppo- cast skies – the sun rarely shines full force. film modules are very efficient even when sed to this, CIS PowerModules are affected And yet, it is precisely in the midst of these shadows are cast over the modules or the only in the covered area. This means higher daily adversities that, thanks to their good surfaces are partly covered up (for instance yields even in the shade. low-light performance, the CIS PowerMo- with leaves). The reason for this can be found dules by Solar Frontier produce more pow- in the different cellular structure. The square There is another advantage to this high sha- er than others. silicon cells in the module are connected in de tolerance: Rows of modules can be moun- substrings. Contrary to this, the long and very ted closer together in free-field installations Due to their wide spectral sensitivity that In practice, the good low-light performance narrow thin-film cells are connected in series. and on industrial flat roofs. This means that is optimized to the luminous density of the of the CIS PowerModules means that the If in conventional silicon modules part of the higher power yields can be achieved in limi- sun, Solar Frontier modules generate more modules generate high yields even under surface is covered up, then not only one cell, ted spaces. kilowatt hours even in weaker light condi- conditions that are unfavorable for crys- tions. Thanks to their sensitivity to red and talline silicon modules. Even on east-west infrared light, they get to work early, gene- roofs, flat roofs or even roofs facing north, rating power in the early morning hours they achieve more operating hours and de- and continuing on into late in the evening; liver more solar energy than any other mo- they can even convert the93 short-wave dif- dule technology. fuse blue light during the day better than 95 90 CIS c-Si other technologies. 100 95 75 65 50 CIS 50 Output (%) 25 c-Si 0 0 20 40 60 80 100 Fig. below: Mounting examples for PV installations with CIS PowerModules Shade (%) shadow shadow c-Si modules CIS PowerModules steady energy c-Si modules produce CIS PowerModules produce steady energy due to their on tilted roof in tilted roof on flat roof in flat roof curtain façade cold/hot façade skylight roofs sun shield production in spite far less under the same shade tolerance, even when part of the cell is shaded of shade conditions Reference: Blandford, United Kingdom Reference: Bottrop, Germany The challenge: poor weather conditions, much rain The challenge: Partial afternoon shade System capacity 41.4 kWp System capacity 42.75 kWp Annual global irradiance 1,091 kWh/m2 Annual global irradiance 950 – 1,000 kWh/m2 Average yearly temperature 10.7 °C Average yearly temperature 9.6 °C Annual precipitation 786.6 mm Annual precipitation 930 mm 4 | CIS CIS | 5 Permission kindly granted by SaveEnergy Greater efficiency: high temperature stability Greater efficiency: „Light Soaking Effect“ Highest yields – Highest yields – and how even in sweltering heat. you reap added benefits. In all photovoltaic modules, output dimini- ven in percent per degree Kelvin (%/°K) in the Now, let‘s say you‘re starting your car on a buffer layer. This buffer layer initially forms an shes with increasing temperatures, which technical data sheet. At an outside tempera- cold winter morning. As long as the motor is energy barrier which hampers the electron results in yield losses. This is why the perfor- ture in excess of 30° Celsius, solar modules still cold it clearly puts out less power. How- flow. Triggered by the photons of the sun- mance of conventional technologies is con- exposed to the heat for hours at a time can ever, the output increases noticeably as soon light, the first electrons begin moving and siderably lower in the summer months or in reach temperatures of up to 70 °C. as the motor has warmed up. The same ap- neutralize the initially still existent defective hot regions, in spite of high sunshine values. plies for what is called the „light soaking ef- areas in the border of the layers. This makes Therefore, especially in the summer and in fect.“ the energy barrier smaller, facilitates the flow CIS PowerModules are less dependent on hot regions, the temperature stability of CIS of the next electrons and reduces the series temperature than crystalline silicon modules PowerModules is a great advantage, which The light soaking effect is the ability of the resistance. As a result, the energy flux at the and therefore exhibit greater temperature is reflected in a higher energy production of module to generate several percent more module and the module efficiency are incre- stability. This is reflected in a low temperature over 10% compared to crystalline modules. output after about 50 hours of sunshine than ased. coefficient of the output, which is usually gi- it could at the time of its production, which was fixed with flash list values (the electrical If the efficiency of a CIS PowerModule increa- characteristics of the PV module under stan- ses to a higher value due to the light soaking dard test conditions - its birth certificate, so effect, it will remain stable over the entire life to speak). cycle. Output losses occurring over the life- time of the modules correspond to the na- 100 The CIS layer applied to the substrate in seve- tural degradation of less than 0.5% per year. 95 CIS ral work steps is topped by a nanometer-thin 90 85 Fig.: Low temperature coefficient means: Output (%) 80 c-Si almost one-third lower energy production losses Confirmed by: at high temperatures 25° >> Module temperature (C°) >> 70° e.g. at a module temperature of 70 °C: CIS PowerModule: -13.9 % c-Si modules CIS PowerModules c-Si module (typ.): -20.3 % Change in maximum output Normalized maximum output 1.2 1.10 1.08 1.1 1.06 measured nominal output 1.04 1.0 Pmax after light soaking 1.02 specied output 1.00 0.9 specied output 0.98 0 0.5 1.0 1.5 2.0 0.8 Reference: Windhoek, Namibia Cumulative solar radiation (kWh/m2) 0 1 2 3 4 5 6 Working life in years The challenge: High daytime and low nighttime temperatures, intense solar radiation Fig.: Pmax drops by 0.5 %/year (10% in 20 years).