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In-situ inspection and measurement of degradation mechanisms for crystalline and thin film PV systems under harsh climatic conditions
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Technologies and Materials for Renewable Energy, Environment and Sustainability, TMREES18, Technologies and Materials for Renewable Energy, and Sustainability, TMREES18, 19–21 September 2018,Environment Athens, Greece 19–21 September 2018, Athens, Greece
In-situ inspection and measurement of degradation mechanisms for In-situ inspection and of degradation mechanisms for crystalline and thinInternational filmmeasurement PVSymposium systems on under harsh conditions The 15th District Heatingclimatic and Cooling crystalline and thin film PV systems under harsh climatic conditions Abdellatif Bouaichia,b, *, Ahmed Alami Merrounib, Charaf Hajjaj b,c, Houssain Zitounib,d, a,b, b thea heat demand-outdoor b,c Assessing the feasibility of using b a Zitounib,d, Abdellatif Bouaichi Ahmed Alami Merrouni , Charaf Hajjaj Messaoudi , Houssain Abdellatif *, Ghennioui , Aumeur El Amrani , Choukri a Abdellatif Ghennioui El Amrani , Choukri temperature function forb, aAumeur long-term district heatMessaoudi demanda forecast OATE Faculty of Sciences and Techniques, P.C 509 Boutalamin 52000, Errachidia, Morocco. 0
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a
a Research Institute for of Solar Energy and New Energies Green52000, EnergyErrachidia, Park, Benguerir, Morocco. OATE Sciences and Techniques, P.C (IRESEN), 509 Boutalamin Morocco. a,b,c Faculty a of science, a doukkali b , El Jadida, c c c b LEIE chouaib university, Morocco. Research Institute for Faculty Solar Energy and New Energies (IRESEN), Green Energy Park, Benguerir, Morocco. c Faculty of science, 4 Avenue Ibn Battouta B.P. 1014 RP, Rabat, Morocco LEIE Faculty of science, chouaib doukkali university, , El Jadida, Morocco. a *[email protected] IN+ Center for Innovation, Technology Policy Research - Instituto Técnico, Av. Rovisco Faculty ofand science, 4 Avenue Ibn BattoutaSuperior B.P. 1014 RP, Rabat, MoroccoPais 1, 1049-001 Lisbon, Portugal b Veolia Recherche & Innovation, 291 Avenue Dreyfous Daniel, 78520 Limay, France *[email protected] c Département Systèmes Énergétiques et Environnement - IMT Atlantique, 4 rue Alfred Kastler, 44300 Nantes, France b
I. Andrić
*, A. Pina , P. Ferrão , J. Fournier ., B. Lacarrière , O. Le Corre
Abstract Abstract Abstract The assessment of photovoltaic (PV) modules performance and reliability at operating conditions is very important considering the investment in PV power plans. One ofperformance the important parameters modules reliabilityisisvery the important degradation rate (Rd). Thelarge assessment of photovoltaic (PV) modules and reliabilityon at PV operating conditions considering District heating are commonly addressed in the literature as calculations. onePV of modules the most effective decreasing the This parameter hasnetworks aninimportant implication on Thereliability aim of this study is for to investigate the the large investment PV power plans. One of the return-on-investment important parameters on issolutions the degradation rate (Rd). greenhouse gashas emissions the building sector. These(m-Si) systems require high(TF) investments which arestudy returned through the the heat degradation rates ofan two PVfrom technologies (monocrystalline and thincalculations. film based) after than two of outdoor This parameter important implication on the return-on-investment The aim ofmore this is toyears investigate sales. Due to the changed climate conditions renovation policies, heat demand in the could decrease, exposure in rates semi-arid conditions. In the first step,and thebuilding performance the(TF) electrical parameters will be each degradation of two PV technologies (monocrystalline (m-Si) anddrop thinof film based) after more thanfuture twoanalysed years of for outdoor prolonging the investment return period. technology. that, conditions. comparison of the the first technologies in harsh will be presented.will Moreover, modules with exposure in After semi-arid In step, the durability performance drop atmosphere of the electrical parameters be analysed for each Thehighest main scope of thiscomparison paper to of assess theselected feasibility of electroluminescence using in theharsh heat demand – outdoor function for heat demand the degradation rate isvalues were for (EL) measurements to Moreover, deeply investigate the technology. After that, the technologies durability atmosphere will betemperature presented. modules with forecast. district Alvalade, located in Lisbon used and as(EL) a 1.73 case study. The district consisted of the 665 degradation. The resultsof show that the average powers Rd are 1.5was %/year %/year for the m-Siisand TF modules the highestThe degradation rate values were selected for(Portugal), electroluminescence measurements to deeply investigate buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district respectively. Those values are significantly higher than those reported either in the literature or those employed in financial degradation. The results show that the average powers Rd are 1.5 %/year and 1.73 %/year for the m-Si and TF modules renovation scenarios were are developed (shallow, intermediate, Toeither estimate theliterature error, obtained heat demand invalues were calculations. respectively. Those values significantly higher than those deep). reported in the or those employed financial compared with results from a dynamic heat demand model, previously developed and validated by the authors. calculations. results showed that when only weatherLtd. change is considered, the margin of error could be acceptable for some applications ©The 2018 The Authors. Published by Elsevier ©(the 2019 The by Ltd. inAuthors. annual demand was lower all weather scenarios considered). However, after introducing renovation This iserror an open accessPublished article under the CCthan BY-NC-ND (https://creativecommons.org/licenses/by-nc-nd/4.0/) © 2018 The Authors. Published by Elsevier Elsevier Ltd.20% for license This is an and open accessvalue article under theupCC BY-NC-ND license on (https://creativecommons.org/licenses/by-nc-nd/4.0/) scenarios, the error increased to 59.5% (depending the weather and renovation considered). Selection peer-review under responsibility of the scientific committee of Technologies andscenarios Materialscombination for Renewable Energy, This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection andofpeer-review under responsibility of the scientific committee of3.8% Technologies and Materials for Renewable Energy, The value slope coefficient increased on average within the range of up to 8% perMaterials decade, for thatRenewable corresponds to the Environment and Sustainability, TMREES18. Selection and peer-review under responsibility of the scientific committee of Technologies and Energy, Environment and Sustainability, TMREES18. decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and Environment and Sustainability, TMREES18. renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the Keywords: Photovoltaic; reliability; semiarid; degradation rate; electroluminescence; white spots. coupled scenarios). The values suggested could degradation be used to modify the function parameterswhite for the scenarios considered, and Keywords: Photovoltaic; reliability; semiarid; rate; electroluminescence; spots. improve the accuracy of heat demand estimations. © 2017 The Authors. Published by Elsevier Ltd. * Corresponding author. Tel.: +212 667 385 106; fax: +212 537 68 27 74. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and E-mail address: [email protected] * Corresponding author. Tel.: +212 667 385 106; fax: +212 537 68 27 74. Cooling. E-mail address: [email protected]
1876-6102 © 2018 The Authors. Published by Elsevier Ltd. Keywords: Heat demand; Forecast; Climate change license (https://creativecommons.org/licenses/by-nc-nd/4.0/) This is an open access under the CC BY-NC-ND 1876-6102 © 2018 Thearticle Authors. Published by Elsevier Ltd. Selection and peer-review under responsibility of the scientific of Technologies and Materials for Renewable Energy, Environment This is an open access article under the CC BY-NC-ND licensecommittee (https://creativecommons.org/licenses/by-nc-nd/4.0/) and Sustainability, TMREES18. Selection and peer-review under responsibility of the scientific committee of Technologies and Materials for Renewable Energy, Environment and Sustainability, TMREES18.
1876-6102 © 2017 The Authors. Published by Elsevier Ltd. 1876-6102 © 2019 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of Technologies and Materials for Renewable Energy, Environment and Sustainability, TMREES18. 10.1016/j.egypro.2018.11.287
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1. Introduction Nomenclature GEP PV TF c-Si m-Si HIT a- Si IRESEN LID SWE STC Gd Rd Pmax Imp Vmp FF EL
Green Energy Park Photovoltaic Thin film crystalline silicon monocrystalline silicon hetro-juntion intrinsic thin layer silicon amorphous silicon Research Institute for Solar Energy and New Energies light induced degradation Staebler-Wronski Effect Standard Test Conditons global degradation degradation rate maximum power maximum power current maximum power voltage fill factor electroluminescence
It’s true that the power output of solar PV systems strongly depends on available meteorological parameters such as solar radiation and ambient temperature which varies with location. However, the system performance is also a significant contributor to the variation/drop of the power output [1]. The yearly variations of the power output, as a function of those parameters, is important to estimate the PV modules lifetime. Moreover, the development of a universal degradation database using on site measurements from specific locations is with high interest to the PV manufacturers and investors to develop PV modules that adaptable to different climates. In recent years, the PV modules reliability has been intensively investigated, especially, in the regions with highsolar-potential, like deserts, arid, temperate and tropical zones, [2-7, 10,26-32]. The main investigated element for the PV reliability study is the degradation rate, as illustrated in fig.1. This figure gathers the areas where the PV modules degradation rate has been calculated for the last 20 years [10]. Numerical simulation is also a way to estimate the modules degradation rate. Several analytical methods have been used in the literature [7-9] to quantify this parameter. These methods use whether continuous data for analysis or the I-V curve data periodically measured. Jordan et al. [10] reported that the average degradation rate for crystalline silicon (c-Si) modules is 0.8– 0.9%/year, whereas, it is around 1%/year for Thin films (TF) modules. These values (according to the authors) may be higher in hotter climates and mounting configurations. Suleske et al. [11] investigated the degradation of a gridtied power plant modules installed at Arizona for 10–17 years. They reported a degradation rates ranging from 0.9%/year to 1.9%/year for non-hot spotted modules, and 5%/year for modules with hot spots. Another interesting study has been conducted at a remote site at the National Centre for Photovoltaic Research & Education (NCPRE) in collaboration with the National Institute of Solar Energy (NISE) in Gurgaon (near New Delhi) [12,13,23]. In this study authors reported a degradation rate of 2.03%/year for monocrystalline silicon (m-Si) PV modules. This value was more than the expected level according to the literature [10]. The same research group evaluated the performance of different PV technologies (a- Si, multi c- Si and HIT) and they found that HIT and a- Si have performed better than multi c- Si [14]. In the same direction, Tamizhmani [15] demonstrated that modules in the hot climates of USA show a higher degradation rate than in other climatic zones.
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Fig. 1. Worldwide reported degradation rates colored by location for 20 years [10].
Back to figure 1, it can be seen that no degradation study has been conducted for Morocco. This country is known with its high solar irradiation records and large capacity to host solar PV power plants [33]. However, Morocco has a harsh dusty atmosphere that can influence the electricity production and the durability of the PV modules [25,34]. The present study is an extension of our previous work on PV module degradation [25]. The aim of this study is to quantify the degradation rates of several PV modules from two different technologies (m-Si and TF based PV modules) exposed for more than two years at Green Energy Park (GEP) research facility. GEP is located at Benguerir (32°13'18.2"N 7°55'44.0"W) a city specified by a semi-arid hot climate. The results show that the average degradation rates are of 1.50 %/year for the m-Si PV modules and 1.73 %/year for TF PV modules which exhibit a large distribution of power degradation. 2. Experimental setup and degradation measurement 2.1. Experimental setup The PV systems investigated in this study are shown in fig. 2. Since August 2014, twelve modules from both technologies (m-Si and TF) were exposed to outdoor conditions. During this period, the TF system was exposed in open circuit and doesn’t used to produce electricity. The technical characteristics of the PV modules used in this study are gathered in Table 1. Table 1: The characteristics of the PV modules used in this study Parameters
Values c-Si
TF
Rated power (W)
285
145
Vmpp (V)
31.3
81
Impp (A)
1.67
1.8
Voc (V)
39.7
107
Isc (A)
9.84
2.2
Power Temperature coefficient (%/°C)
-0.41
-0.31
Voltage Temperature coefficient (%/°C)
-0.30
-0.30
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Fig. 2. The investigated PV system on GEP, Benguerir, Morocco (Source: picture taken by the authors at Green Energy Park).
The systems were exposed at GEP (32.22°N, 7.93°W). This location in a semi-arid region that is known for the lack of precipitations (total rain 74.6mm from March 2016 to March 2017), high temperatures in the summer (more than 26 days with a maximum temperature of over 40°C in 2016), an annual average humidity of 60.6% and an annual solar irradiation of 5480Wh/m2/day. In this study, the I-V curve tracer PVPM1000CX (Figure 3) was used to measure the electrical parameters of the PV modules. The I-V tracer was performed after the cleaning of PV modules to eliminate the non-permanent effect like dust. This device is calibrated regularly. It includes a m-Si reference cell that reads the irradiance in the tilted plane. Also, it’s equipped with a PT1000 thermal sensor to measure the module’s temperature. The I-V curve converts the measured values to Standard Test conditions (STC; 1000 W/m2, 25°C, A.M1.5) to give comparative measures in different irradiance and temperature conditions. The characteristics of the device are listed in Table 2.
Fig. 3. Photograph of used I-V tracer (Source: picture taken by the authors at Green Energy Park).
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Table 2: Technical characteristics of the I-V curve tracer PVPM1000CX. Sampling rate Resolution Accuracy of the a/d converter Accuracy Peak power measurement Reproducement Duration of single measurement
Max. 100kHz 0.01V - 0.25V, 0.005A – 0.01A 0.08% of FSR±1 LSB ±5% ±2-3% 20ms up to 2 seconds, avoiding the influence of capacitive properties of the module under test 25V / 100V / 500V / 1000V 2A / 5A / 10A / 20A -40°C - +100°C with Pt1000 0 - 1300W/m2 (Standard sensor)
Voltage Current Temperature Irradiance
2.2. Degradation measurement The main objective of our measurement campaign is to evaluate the degradation effect on m-Si and TF PV modules performance exposed in our field. To evaluate this parameter, we will focus on the electrical parameters obtained during the measurement campaign using the I-V tracer. Before any measurement, the selected modules were cleaned to eliminate the impact of dust on the modules performance drop. Only measurements recorded at irradiances between 950 W/m2 and 1050 W/m2 were considered in order to minimise the translation error to STC and to be as close as possible to the STC data provided by the manufacturer. For the determination of the degradation rates, the initial I-V data at the time of installation is desirable, but, usually people use the name plate information as reference. Those data were used as reference data in our study as well. The global degradation (Gd) calculates the performance drop of a considered PV module parameter from the initial values, up to the experiment day by comparing the STC translated data with the ‘nominal’ rating, using the analytical equation [25]:
Gd Y
%
(1
Y ) 100 Y0
(1)
Y represents the current measurement of the module’s electrical parameters power (Pmax), maximum power current (Imp) maximum power voltage (Vmp) and fill factor (FF), while, Y0 represent the reference/Nominal values of those parameters. The latest ones are given by the manufacturer in the datasheet under STC. The degradation rate (Rd) is calculated from the global degradation factor using eq.2. In this equation ∆t represents the module’s exposure period (in years) from the first operation day until the test date.
R d Y
%
G ( d) t
(2)
In the present paper, degradation of Pmax, Imp, Vmp and FF has been normalized over the period of 2.5 years operation (%degradation/year). 3. Result and discussion Fig. 4 presents the degradation rates distribution, measured with equation 1 and 2, for each module and for both technologies. The PV modules electrical parameters measurement was conducted on March 2017. As it can be seen, the TF based PV modules are the ones suffering from the highest degradation rates. This may be attributed to the stabilization period and the light induced degradation (LID) failure or Staebler-Wronski effect (SWE) which is a reversible effect [36]. The wide distribution of the Rd in fig. 4 and Table 3 is completely reasonable. This has been confirmed in the
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literature, where authors present different degradation rates for modules from the same technology, same design, and same manufacturer and exposed for the same period [20-22]. This performance drop is mainly due to the modules power variability, during the first year of operation. We need to mention that the TF modules power can stabilise after the first year, thus, the Rd may decrease over time [24]. Back to fig. 4, non-negative Rd values have been noticed for both technologies. For TF technology, 66% of the values excess 1%/year with a maximum Rd of 4.5%/year. The average Rd, however, is around 1.73%/year. Regarding the c-Si technology, the Rd values are, more or less, homogeneous. The values distribution is between 1 and 2%/year with an average of 1.5 %/year. In order to compare the Rd values found under our climate with other climates, we summarized different values found in the literature in Table 4. As it can be seen the m-Si modules are less affected in comparison of TF technology. In fact, m-Si generally exhibits degradation rates below 1%/year, while, TF technologies showed rates above 1%/year. This is also confirmed by Jordan et al [10] who summarized the Rd values from 200 studies in 40 different locations, where the Rd values of the Silicon based technologies is between 0.8 and 0.9%/year. These values are lower than what we found in our measurement campaign, where the Rd values of the m-Si technology are between 1 and 2%/years. This is mainly due to the harsh atmosphere in Morocco, which is in accordance with other regions with harsh atmosphere like India, where it has been reported that Rd values are of 2.03%/year for Powai [23] and 1.9%/year in Mumbai [20].
Fig. 4. Degradation rate distribution for investigated c-Si and TF PV modules. Table 3: Variation of measured degradation rates Degradation rate (%/year) Nominal rating
Average
Min
Max
c-Si
285
1.50
1.02
1.94
TF
145
1.73
0.53
4.35
Another important remark from the previous studies is that the degradation process follows two different stages: a rapid degradation for the first years of exposure with 1 to 3%/years [18] followed by a slow linear degradation rate of 0.5 to 1%/year. We are working on the determination of the Rd behaviour under Moroccan climate; however, this
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is not the context of the current paper, that’s why we will focus only on the degradation effects on the electrical parameters. Table 4: Summary of degradation rate values for differences climate zones in the world
Location
Climate
Outdoor exposition (years)
Perth (Australia)
Temperate
1.3-1.5
Mesa, Arizona (USA)
Desert
Modules technology
Degradation rate (%/years)
c-Si
0.5-2.7
TF
18.8
2.4-4
c-Si
0.4
2.7
TF
3.52
6.7
TF
1.16
Reference
[26]
[27]
Golden, Colorado (USA)
Mountain continental
8
c-Si
0.75
[28]
Hamamatsu (Japan)
Temperate
10
c-Si
0.62
[29]
Trinidad, California (USA)
Cool coastal
11
c-Si
0.4
[30]
Lugano (Swizeland)
Temperate
20
c-Si
0.53
[31]
Ispra (Italy)
Temperate
22
c-Si
0.67
[32]
Benguerir (Morocco)
Desert
2.5
c-Si
1.5
Present study
TF
1.73
Present study
Fig. 5 presents the degradation rates of the main electrical parameters (maximum power current (Imp) maximum power voltage (Vmp) and fill factor (FF)) for both technologies. As clearly seen, for the m-Si technology, the highly affected parameter is the Imp followed by the Vmp, while the FF can be considered as not affected. Therefore, we can say that for the m-Si modules, the power degradation is mainly due to the current’s performance drop. The degradation in current is mainly due to cracks at the cell level, discoloration and delamination which reduce the optical transmittance and sunlight reaching the cell, thus, the photo-generated current inside the module [16,17,23]. Defects in the material of the cell, micro-cracks, broken metallization, shunts, and inactive regions are detected via EL imaging. EL imaging carried out in the dark with the PV module in forward-bias at near Voc using a DC power supply, and is based on light emission around 1100nm as a result of the radiative recombination of carriers [35]. Fig. 6 shows the EL images of the investigated m-Si PV modules. The predominant PV module failure is the micro crack defect. This failure is the main cause of the current performance drop, thus, the power loss. In regards of TF technology, the Vmp is the highly affected parameter and it’s the one that causes the loss in the modules performance. As seen in fig. 7, a visual defect is detected at GEP. This defect is called “white spots” which is rarely reported in the literature. It’s mostly due to improper cleaning of the substrate glass during the manufacturing process leading to embedded impurities [19, 23]. This defect can be aggravated in harsh climate areas, which will lead to a drop in the modules performance.
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Fig. 5. The main electrical parameters degradation for m-Si and TF investigated PV modules.
Micro-cracks
Fig. 6. EL image of m-Si module with high Rd (Source: EL image taken by the authors at Green Energy Park).
White spot
Fig. 7. White spot on TF PV module observed at GEP field (Source: picture taken by the authors at Green Energy Park).
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4. Conclusion Field data obtained after 2.5 years of twelve PV module of both TF and m-Si technology have been analysed. For TF technology, 66% of degradation rate values excess 1%/year with a maximum of 4.5%/year. The average degradation rate, however, is around 1.73%/year. Regarding the c-Si technology, the degradation rate values are, more or less, homogeneous. The values distribution is between 1 and 2%/year with an average of 1.5 %/year. These values are relatively higher than what we found in literature. Where, some authors highlighted that m-Si generally exhibits degradation rate below 1%/year, while TF technologies showed rates above 1%/year. This is mainly due to the harsh atmosphere in Morocco. On the other hand, other regions with harsh atmosphere like India where it has been reported that degradation rate values for m-Si are of 2.03%/year and 1.9%/year. Regarding the other electrical parameters, we can say that for m-Si the power degradation is mainly due to the current’s performance drop followed by Vmp, and lastly by FF. In regards of TF technology, the Vmp is the highly affected parameter and it’s the one that causes the loss in the modules performance. Using the EL images, the predominant PV module failure for m-Si is the micro crack defect. However, TF PV module, a so-called white spot has been noticed. This work provides new information on the degradation issue of various studied solar panels in desert conditions. Indeed, we have not identified such a study in this region despite the fact that the region has one of the best solar potential in the world with 4000 h of sunshine per year. In the full paper, degradation rates of more than 500 PV modules from both technologies and from 14 different manufacturers with various mounting type and exposed period will be presented. Acknowledgements This work is supported by IRESEN the Research Institute for Solar Energy and Renewable Energy. References [1]. J. Hernandez-Moro, J.M. Martinez-Duart, Analytical model for solar PV and CSP electicity costs: present LCOE values and their future evolution, Renewable and Sustainable Energy Reviews. 20 , 119e132, 2013. [2]. V. Sharma, O.S. Sastry, A. Kumar, B. Bora, S.S. Chandel, Degradation analysis of a-Si, (HIT) hetro-juntion intrinsic thin layer silicon and m-C-Si solar photovoltaic technologies under outdoor conditions, Energy 72 , 536e546; 2014. [3]. F. Bandou, A.H. Arab, M. S.Belkaid, P.O. Logerais, O. Riou, A. Charki, Evaluation performance of photovoltaic modules after a long time operation in Saharan environment, Int. J. Hydrog. Energy 40 , 13839e13848, 2015. [4]. B. Raghuraman, V. Laksman, J. Kuitche,W. Shisler, G. Tamizhani, H. Kapoor, An overview of SMUDs outdoor photovoltaic test program at Arizona State University, in: Proc. 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[16]. Jordan, D. C., J. H. Wohlgemuth, and S. R. Kurtz. Technology and climate trends in PV module degradation. Proceedings of the 27th European Photovoltaic Specialists Conference and Exhibition, Frankfurt, Pp. 3118–3124, 2012. [17]. El Amrani, A., El Amraoui, M., El Abbassi, A., & Messaoudi, C. Nonlinear phenomenon in monocrystalline silicon based PV module for low power system: Lead acid battery for low energy storage. Superlattices and Microstructures, 75, 39-46, (2014. [18]. Osterwald CR, Benner JP, Pruett J, Anderberg A, Rummeland S, Ottoson L. Degradation in weathered crystalline-silicon PV modules apparently caused by UV radiation. 3rd World Conference on Photovoltaic Energy Conversion, Osaka, Japan; pp. 2911–2915, 2003. [19]. Kontges, M., S. Kurtz, C. Packard, U. Jahn, K. A. Berger, K. Kato. T. Friesen et al. 2014. Review of failures of photovoltaic modules. International Energy Agency Report No. IEA-PVPS T13-01:2014. [20]. RAJPUT, Pramod, TIWARI, G. N., SASTRY, O. S., et al. Degradation of mono-crystalline photovoltaic modules after 22years of outdoor exposure in the composite climate of India. Solar Energy, vol. 135, p. 786-795, 2016. [21]. KUMAR, Manish et KUMAR, Arun. Performance assessment and degradation analysis of solar photovoltaic technologies: A review. Renewable and Sustainable Energy Reviews, vol. 78, p. 554-587, 2017. [22]. KAHOUL, Nabil, CHENNI, Rachid, CHEGHIB, Hocine, et al. Evaluating the reliability of crystalline silicon photovoltaic modules in harsh environment. Renewable Energy, vol. 109, p. 66-72, 2017. [23]. DUBEY, Rajiv, CHATTOPADHYAY, Shashwata, KUTHANAZHI, Vivek, et al. Comprehensive study of performance degradation of field-mounted photovoltaic modules in India. Energy Science & Engineering, vol. 5, no 1, p. 51-64, 2017. [24]. VÁZQUEZ, Manuel et REY-STOLLE, Ignacio. Photovoltaic module reliability model based on field degradation studies. Progress in photovoltaics: Research and Applications, vol. 16, no 5, p. 419-433, 2008. [25]. A. Bouaichi, A. Alami Merrouni, A. El Hassani, Z. Naimi, B. Ikken, A. Ghennioui, A. Benazzouz, A. El Amrani, C. Messaoudi. Experimental evaluation of the discoloration effect on PV-modules performance drop. Energy Procedia; 119 :818-827, 2017. [26]. Carr AJ, Pryor TL. A comparison of the performance of different PV module types in temperate climates. Solar Energy; 76: 285–294, 2004. [27]. Raghuraman B, Laksman V, Kuitche J, Shisler W,Tamizhani G, Kapoor H. An overview of SMUDs outdoor photovoltaic test program at Arizona State University. 2006 IEEE 4th IEEE World Conference on Photovoltaic Energy Conversion, Hawaii, USA, 2006. [28]. Marion B, Adelstein J. Long-term performance of the SERF PV systems. NCPV and Solar Program Review Meeting, 2003. [29]. Sakamoto S, Oshiro T. Dominant degradation of crystalline silicon photovoltaic modules manufactures in 1990 ´s. 20th European Photovoltaic Solar Energy Conference, Barcelona,; pp. 2155–2158, 2005. [30]. Reis AM, Coleman NT, Marshall MW, Lehman PA, Chamberlain CE. Comparison of PV module performance before and after 11-years of field exposure. Proceedings of the 29th IEEE Photovoltaic Specialists Conference, New Orleans, Louisiana, USA, 2002. [31]. Realini A, Bura ´ E, Cereghetti N, Chianese D, Rezzonico S. Study of 20-year old PV plant (MTBF Project). 17th EPVSEC, Munich, Germany, 2001. [32]. Dunlop ED, Halton D. The performance of crystalline silicon photovoltaic solar modules after 22 years of continous outdoor esposure. Progress in Photovoltaics: Research and Applications; 14: 53–64, 2006. [33]. A.Alami Merrouni, Abd. Mezrhab , A. Mezrhab. PV sites suitability analysis in the Eastern region of Morocco. Sustainable Energy Technologies and Assessments; 18: 6–15, 2016. [34]. A. Alami Merrouni, F. Wolfertstetter, A. Mezrhab, S. Wilbert, R. Pitz-Paal. Investigation of Soiling Effect on Different Solar Mirror Materials under Moroccan Climate. Energy Procedia; 69 :1948-1957, 2015. [35]. KAPLANI, Eleni. Degradation in Field-aged Crystalline Silicon Photovoltaic Modules and Diagnosis using Electroluminescence Imaging. 2016. [36]. SHAH, Arvind Victor (ed.). Thin-film silicon solar cells. CRC Press, 2010.
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Technologies and Materials for Renewable Energy, Environment and Sustainability, TMREES18, Technologies and Materials for Renewable Energy, and Sustainability, TMREES18, 19–21 September 2018,Environment Athens, Greece 19–21 September 2018, Athens, Greece
In-situ inspection and measurement of degradation mechanisms for In-situ inspection and of degradation mechanisms for crystalline and thinInternational filmmeasurement PVSymposium systems on under harsh conditions The 15th District Heatingclimatic and Cooling crystalline and thin film PV systems under harsh climatic conditions Abdellatif Bouaichia,b, *, Ahmed Alami Merrounib, Charaf Hajjaj b,c, Houssain Zitounib,d, a,b, b thea heat demand-outdoor b,c Assessing the feasibility of using b a Zitounib,d, Abdellatif Bouaichi Ahmed Alami Merrouni , Charaf Hajjaj Messaoudi , Houssain Abdellatif *, Ghennioui , Aumeur El Amrani , Choukri a Abdellatif Ghennioui El Amrani , Choukri temperature function forb, aAumeur long-term district heatMessaoudi demanda forecast OATE Faculty of Sciences and Techniques, P.C 509 Boutalamin 52000, Errachidia, Morocco. 0
F
0
F
a
a Research Institute for of Solar Energy and New Energies Green52000, EnergyErrachidia, Park, Benguerir, Morocco. OATE Sciences and Techniques, P.C (IRESEN), 509 Boutalamin Morocco. a,b,c Faculty a of science, a doukkali b , El Jadida, c c c b LEIE chouaib university, Morocco. Research Institute for Faculty Solar Energy and New Energies (IRESEN), Green Energy Park, Benguerir, Morocco. c Faculty of science, 4 Avenue Ibn Battouta B.P. 1014 RP, Rabat, Morocco LEIE Faculty of science, chouaib doukkali university, , El Jadida, Morocco. a *[email protected] IN+ Center for Innovation, Technology Policy Research - Instituto Técnico, Av. Rovisco Faculty ofand science, 4 Avenue Ibn BattoutaSuperior B.P. 1014 RP, Rabat, MoroccoPais 1, 1049-001 Lisbon, Portugal b Veolia Recherche & Innovation, 291 Avenue Dreyfous Daniel, 78520 Limay, France *[email protected] c Département Systèmes Énergétiques et Environnement - IMT Atlantique, 4 rue Alfred Kastler, 44300 Nantes, France b
I. Andrić
*, A. Pina , P. Ferrão , J. Fournier ., B. Lacarrière , O. Le Corre
Abstract Abstract Abstract The assessment of photovoltaic (PV) modules performance and reliability at operating conditions is very important considering the investment in PV power plans. One ofperformance the important parameters modules reliabilityisisvery the important degradation rate (Rd). Thelarge assessment of photovoltaic (PV) modules and reliabilityon at PV operating conditions considering District heating are commonly addressed in the literature as calculations. onePV of modules the most effective decreasing the This parameter hasnetworks aninimportant implication on Thereliability aim of this study is for to investigate the the large investment PV power plans. One of the return-on-investment important parameters on issolutions the degradation rate (Rd). greenhouse gashas emissions the building sector. These(m-Si) systems require high(TF) investments which arestudy returned through the the heat degradation rates ofan two PVfrom technologies (monocrystalline and thincalculations. film based) after than two of outdoor This parameter important implication on the return-on-investment The aim ofmore this is toyears investigate sales. Due to the changed climate conditions renovation policies, heat demand in the could decrease, exposure in rates semi-arid conditions. In the first step,and thebuilding performance the(TF) electrical parameters will be each degradation of two PV technologies (monocrystalline (m-Si) anddrop thinof film based) after more thanfuture twoanalysed years of for outdoor prolonging the investment return period. technology. that, conditions. comparison of the the first technologies in harsh will be presented.will Moreover, modules with exposure in After semi-arid In step, the durability performance drop atmosphere of the electrical parameters be analysed for each Thehighest main scope of thiscomparison paper to of assess theselected feasibility of electroluminescence using in theharsh heat demand – outdoor function for heat demand the degradation rate isvalues were for (EL) measurements to Moreover, deeply investigate the technology. After that, the technologies durability atmosphere will betemperature presented. modules with forecast. district Alvalade, located in Lisbon used and as(EL) a 1.73 case study. The district consisted of the 665 degradation. The resultsof show that the average powers Rd are 1.5was %/year %/year for the m-Siisand TF modules the highestThe degradation rate values were selected for(Portugal), electroluminescence measurements to deeply investigate buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district respectively. Those values are significantly higher than those reported either in the literature or those employed in financial degradation. The results show that the average powers Rd are 1.5 %/year and 1.73 %/year for the m-Si and TF modules renovation scenarios were are developed (shallow, intermediate, Toeither estimate theliterature error, obtained heat demand invalues were calculations. respectively. Those values significantly higher than those deep). reported in the or those employed financial compared with results from a dynamic heat demand model, previously developed and validated by the authors. calculations. results showed that when only weatherLtd. change is considered, the margin of error could be acceptable for some applications ©The 2018 The Authors. Published by Elsevier ©(the 2019 The by Ltd. inAuthors. annual demand was lower all weather scenarios considered). However, after introducing renovation This iserror an open accessPublished article under the CCthan BY-NC-ND (https://creativecommons.org/licenses/by-nc-nd/4.0/) © 2018 The Authors. Published by Elsevier Elsevier Ltd.20% for license This is an and open accessvalue article under theupCC BY-NC-ND license on (https://creativecommons.org/licenses/by-nc-nd/4.0/) scenarios, the error increased to 59.5% (depending the weather and renovation considered). Selection peer-review under responsibility of the scientific committee of Technologies andscenarios Materialscombination for Renewable Energy, This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection andofpeer-review under responsibility of the scientific committee of3.8% Technologies and Materials for Renewable Energy, The value slope coefficient increased on average within the range of up to 8% perMaterials decade, for thatRenewable corresponds to the Environment and Sustainability, TMREES18. Selection and peer-review under responsibility of the scientific committee of Technologies and Energy, Environment and Sustainability, TMREES18. decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and Environment and Sustainability, TMREES18. renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the Keywords: Photovoltaic; reliability; semiarid; degradation rate; electroluminescence; white spots. coupled scenarios). The values suggested could degradation be used to modify the function parameterswhite for the scenarios considered, and Keywords: Photovoltaic; reliability; semiarid; rate; electroluminescence; spots. improve the accuracy of heat demand estimations. © 2017 The Authors. Published by Elsevier Ltd. * Corresponding author. Tel.: +212 667 385 106; fax: +212 537 68 27 74. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and E-mail address: [email protected] * Corresponding author. Tel.: +212 667 385 106; fax: +212 537 68 27 74. Cooling. E-mail address: [email protected]
1876-6102 © 2018 The Authors. Published by Elsevier Ltd. Keywords: Heat demand; Forecast; Climate change license (https://creativecommons.org/licenses/by-nc-nd/4.0/) This is an open access under the CC BY-NC-ND 1876-6102 © 2018 Thearticle Authors. Published by Elsevier Ltd. Selection and peer-review under responsibility of the scientific of Technologies and Materials for Renewable Energy, Environment This is an open access article under the CC BY-NC-ND licensecommittee (https://creativecommons.org/licenses/by-nc-nd/4.0/) and Sustainability, TMREES18. Selection and peer-review under responsibility of the scientific committee of Technologies and Materials for Renewable Energy, Environment and Sustainability, TMREES18.
1876-6102 © 2017 The Authors. Published by Elsevier Ltd. 1876-6102 © 2019 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection and peer-review under responsibility of the scientific committee of Technologies and Materials for Renewable Energy, Environment and Sustainability, TMREES18. 10.1016/j.egypro.2018.11.287
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1. Introduction Nomenclature GEP PV TF c-Si m-Si HIT a- Si IRESEN LID SWE STC Gd Rd Pmax Imp Vmp FF EL
Green Energy Park Photovoltaic Thin film crystalline silicon monocrystalline silicon hetro-juntion intrinsic thin layer silicon amorphous silicon Research Institute for Solar Energy and New Energies light induced degradation Staebler-Wronski Effect Standard Test Conditons global degradation degradation rate maximum power maximum power current maximum power voltage fill factor electroluminescence
It’s true that the power output of solar PV systems strongly depends on available meteorological parameters such as solar radiation and ambient temperature which varies with location. However, the system performance is also a significant contributor to the variation/drop of the power output [1]. The yearly variations of the power output, as a function of those parameters, is important to estimate the PV modules lifetime. Moreover, the development of a universal degradation database using on site measurements from specific locations is with high interest to the PV manufacturers and investors to develop PV modules that adaptable to different climates. In recent years, the PV modules reliability has been intensively investigated, especially, in the regions with highsolar-potential, like deserts, arid, temperate and tropical zones, [2-7, 10,26-32]. The main investigated element for the PV reliability study is the degradation rate, as illustrated in fig.1. This figure gathers the areas where the PV modules degradation rate has been calculated for the last 20 years [10]. Numerical simulation is also a way to estimate the modules degradation rate. Several analytical methods have been used in the literature [7-9] to quantify this parameter. These methods use whether continuous data for analysis or the I-V curve data periodically measured. Jordan et al. [10] reported that the average degradation rate for crystalline silicon (c-Si) modules is 0.8– 0.9%/year, whereas, it is around 1%/year for Thin films (TF) modules. These values (according to the authors) may be higher in hotter climates and mounting configurations. Suleske et al. [11] investigated the degradation of a gridtied power plant modules installed at Arizona for 10–17 years. They reported a degradation rates ranging from 0.9%/year to 1.9%/year for non-hot spotted modules, and 5%/year for modules with hot spots. Another interesting study has been conducted at a remote site at the National Centre for Photovoltaic Research & Education (NCPRE) in collaboration with the National Institute of Solar Energy (NISE) in Gurgaon (near New Delhi) [12,13,23]. In this study authors reported a degradation rate of 2.03%/year for monocrystalline silicon (m-Si) PV modules. This value was more than the expected level according to the literature [10]. The same research group evaluated the performance of different PV technologies (a- Si, multi c- Si and HIT) and they found that HIT and a- Si have performed better than multi c- Si [14]. In the same direction, Tamizhmani [15] demonstrated that modules in the hot climates of USA show a higher degradation rate than in other climatic zones.
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Fig. 1. Worldwide reported degradation rates colored by location for 20 years [10].
Back to figure 1, it can be seen that no degradation study has been conducted for Morocco. This country is known with its high solar irradiation records and large capacity to host solar PV power plants [33]. However, Morocco has a harsh dusty atmosphere that can influence the electricity production and the durability of the PV modules [25,34]. The present study is an extension of our previous work on PV module degradation [25]. The aim of this study is to quantify the degradation rates of several PV modules from two different technologies (m-Si and TF based PV modules) exposed for more than two years at Green Energy Park (GEP) research facility. GEP is located at Benguerir (32°13'18.2"N 7°55'44.0"W) a city specified by a semi-arid hot climate. The results show that the average degradation rates are of 1.50 %/year for the m-Si PV modules and 1.73 %/year for TF PV modules which exhibit a large distribution of power degradation. 2. Experimental setup and degradation measurement 2.1. Experimental setup The PV systems investigated in this study are shown in fig. 2. Since August 2014, twelve modules from both technologies (m-Si and TF) were exposed to outdoor conditions. During this period, the TF system was exposed in open circuit and doesn’t used to produce electricity. The technical characteristics of the PV modules used in this study are gathered in Table 1. Table 1: The characteristics of the PV modules used in this study Parameters
Values c-Si
TF
Rated power (W)
285
145
Vmpp (V)
31.3
81
Impp (A)
1.67
1.8
Voc (V)
39.7
107
Isc (A)
9.84
2.2
Power Temperature coefficient (%/°C)
-0.41
-0.31
Voltage Temperature coefficient (%/°C)
-0.30
-0.30
4
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Fig. 2. The investigated PV system on GEP, Benguerir, Morocco (Source: picture taken by the authors at Green Energy Park).
The systems were exposed at GEP (32.22°N, 7.93°W). This location in a semi-arid region that is known for the lack of precipitations (total rain 74.6mm from March 2016 to March 2017), high temperatures in the summer (more than 26 days with a maximum temperature of over 40°C in 2016), an annual average humidity of 60.6% and an annual solar irradiation of 5480Wh/m2/day. In this study, the I-V curve tracer PVPM1000CX (Figure 3) was used to measure the electrical parameters of the PV modules. The I-V tracer was performed after the cleaning of PV modules to eliminate the non-permanent effect like dust. This device is calibrated regularly. It includes a m-Si reference cell that reads the irradiance in the tilted plane. Also, it’s equipped with a PT1000 thermal sensor to measure the module’s temperature. The I-V curve converts the measured values to Standard Test conditions (STC; 1000 W/m2, 25°C, A.M1.5) to give comparative measures in different irradiance and temperature conditions. The characteristics of the device are listed in Table 2.
Fig. 3. Photograph of used I-V tracer (Source: picture taken by the authors at Green Energy Park).
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Table 2: Technical characteristics of the I-V curve tracer PVPM1000CX. Sampling rate Resolution Accuracy of the a/d converter Accuracy Peak power measurement Reproducement Duration of single measurement
Max. 100kHz 0.01V - 0.25V, 0.005A – 0.01A 0.08% of FSR±1 LSB ±5% ±2-3% 20ms up to 2 seconds, avoiding the influence of capacitive properties of the module under test 25V / 100V / 500V / 1000V 2A / 5A / 10A / 20A -40°C - +100°C with Pt1000 0 - 1300W/m2 (Standard sensor)
Voltage Current Temperature Irradiance
2.2. Degradation measurement The main objective of our measurement campaign is to evaluate the degradation effect on m-Si and TF PV modules performance exposed in our field. To evaluate this parameter, we will focus on the electrical parameters obtained during the measurement campaign using the I-V tracer. Before any measurement, the selected modules were cleaned to eliminate the impact of dust on the modules performance drop. Only measurements recorded at irradiances between 950 W/m2 and 1050 W/m2 were considered in order to minimise the translation error to STC and to be as close as possible to the STC data provided by the manufacturer. For the determination of the degradation rates, the initial I-V data at the time of installation is desirable, but, usually people use the name plate information as reference. Those data were used as reference data in our study as well. The global degradation (Gd) calculates the performance drop of a considered PV module parameter from the initial values, up to the experiment day by comparing the STC translated data with the ‘nominal’ rating, using the analytical equation [25]:
Gd Y
%
(1
Y ) 100 Y0
(1)
Y represents the current measurement of the module’s electrical parameters power (Pmax), maximum power current (Imp) maximum power voltage (Vmp) and fill factor (FF), while, Y0 represent the reference/Nominal values of those parameters. The latest ones are given by the manufacturer in the datasheet under STC. The degradation rate (Rd) is calculated from the global degradation factor using eq.2. In this equation ∆t represents the module’s exposure period (in years) from the first operation day until the test date.
R d Y
%
G ( d) t
(2)
In the present paper, degradation of Pmax, Imp, Vmp and FF has been normalized over the period of 2.5 years operation (%degradation/year). 3. Result and discussion Fig. 4 presents the degradation rates distribution, measured with equation 1 and 2, for each module and for both technologies. The PV modules electrical parameters measurement was conducted on March 2017. As it can be seen, the TF based PV modules are the ones suffering from the highest degradation rates. This may be attributed to the stabilization period and the light induced degradation (LID) failure or Staebler-Wronski effect (SWE) which is a reversible effect [36]. The wide distribution of the Rd in fig. 4 and Table 3 is completely reasonable. This has been confirmed in the
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literature, where authors present different degradation rates for modules from the same technology, same design, and same manufacturer and exposed for the same period [20-22]. This performance drop is mainly due to the modules power variability, during the first year of operation. We need to mention that the TF modules power can stabilise after the first year, thus, the Rd may decrease over time [24]. Back to fig. 4, non-negative Rd values have been noticed for both technologies. For TF technology, 66% of the values excess 1%/year with a maximum Rd of 4.5%/year. The average Rd, however, is around 1.73%/year. Regarding the c-Si technology, the Rd values are, more or less, homogeneous. The values distribution is between 1 and 2%/year with an average of 1.5 %/year. In order to compare the Rd values found under our climate with other climates, we summarized different values found in the literature in Table 4. As it can be seen the m-Si modules are less affected in comparison of TF technology. In fact, m-Si generally exhibits degradation rates below 1%/year, while, TF technologies showed rates above 1%/year. This is also confirmed by Jordan et al [10] who summarized the Rd values from 200 studies in 40 different locations, where the Rd values of the Silicon based technologies is between 0.8 and 0.9%/year. These values are lower than what we found in our measurement campaign, where the Rd values of the m-Si technology are between 1 and 2%/years. This is mainly due to the harsh atmosphere in Morocco, which is in accordance with other regions with harsh atmosphere like India, where it has been reported that Rd values are of 2.03%/year for Powai [23] and 1.9%/year in Mumbai [20].
Fig. 4. Degradation rate distribution for investigated c-Si and TF PV modules. Table 3: Variation of measured degradation rates Degradation rate (%/year) Nominal rating
Average
Min
Max
c-Si
285
1.50
1.02
1.94
TF
145
1.73
0.53
4.35
Another important remark from the previous studies is that the degradation process follows two different stages: a rapid degradation for the first years of exposure with 1 to 3%/years [18] followed by a slow linear degradation rate of 0.5 to 1%/year. We are working on the determination of the Rd behaviour under Moroccan climate; however, this
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is not the context of the current paper, that’s why we will focus only on the degradation effects on the electrical parameters. Table 4: Summary of degradation rate values for differences climate zones in the world
Location
Climate
Outdoor exposition (years)
Perth (Australia)
Temperate
1.3-1.5
Mesa, Arizona (USA)
Desert
Modules technology
Degradation rate (%/years)
c-Si
0.5-2.7
TF
18.8
2.4-4
c-Si
0.4
2.7
TF
3.52
6.7
TF
1.16
Reference
[26]
[27]
Golden, Colorado (USA)
Mountain continental
8
c-Si
0.75
[28]
Hamamatsu (Japan)
Temperate
10
c-Si
0.62
[29]
Trinidad, California (USA)
Cool coastal
11
c-Si
0.4
[30]
Lugano (Swizeland)
Temperate
20
c-Si
0.53
[31]
Ispra (Italy)
Temperate
22
c-Si
0.67
[32]
Benguerir (Morocco)
Desert
2.5
c-Si
1.5
Present study
TF
1.73
Present study
Fig. 5 presents the degradation rates of the main electrical parameters (maximum power current (Imp) maximum power voltage (Vmp) and fill factor (FF)) for both technologies. As clearly seen, for the m-Si technology, the highly affected parameter is the Imp followed by the Vmp, while the FF can be considered as not affected. Therefore, we can say that for the m-Si modules, the power degradation is mainly due to the current’s performance drop. The degradation in current is mainly due to cracks at the cell level, discoloration and delamination which reduce the optical transmittance and sunlight reaching the cell, thus, the photo-generated current inside the module [16,17,23]. Defects in the material of the cell, micro-cracks, broken metallization, shunts, and inactive regions are detected via EL imaging. EL imaging carried out in the dark with the PV module in forward-bias at near Voc using a DC power supply, and is based on light emission around 1100nm as a result of the radiative recombination of carriers [35]. Fig. 6 shows the EL images of the investigated m-Si PV modules. The predominant PV module failure is the micro crack defect. This failure is the main cause of the current performance drop, thus, the power loss. In regards of TF technology, the Vmp is the highly affected parameter and it’s the one that causes the loss in the modules performance. As seen in fig. 7, a visual defect is detected at GEP. This defect is called “white spots” which is rarely reported in the literature. It’s mostly due to improper cleaning of the substrate glass during the manufacturing process leading to embedded impurities [19, 23]. This defect can be aggravated in harsh climate areas, which will lead to a drop in the modules performance.
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Fig. 5. The main electrical parameters degradation for m-Si and TF investigated PV modules.
Micro-cracks
Fig. 6. EL image of m-Si module with high Rd (Source: EL image taken by the authors at Green Energy Park).
White spot
Fig. 7. White spot on TF PV module observed at GEP field (Source: picture taken by the authors at Green Energy Park).
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4. Conclusion Field data obtained after 2.5 years of twelve PV module of both TF and m-Si technology have been analysed. For TF technology, 66% of degradation rate values excess 1%/year with a maximum of 4.5%/year. The average degradation rate, however, is around 1.73%/year. Regarding the c-Si technology, the degradation rate values are, more or less, homogeneous. The values distribution is between 1 and 2%/year with an average of 1.5 %/year. These values are relatively higher than what we found in literature. Where, some authors highlighted that m-Si generally exhibits degradation rate below 1%/year, while TF technologies showed rates above 1%/year. This is mainly due to the harsh atmosphere in Morocco. On the other hand, other regions with harsh atmosphere like India where it has been reported that degradation rate values for m-Si are of 2.03%/year and 1.9%/year. Regarding the other electrical parameters, we can say that for m-Si the power degradation is mainly due to the current’s performance drop followed by Vmp, and lastly by FF. In regards of TF technology, the Vmp is the highly affected parameter and it’s the one that causes the loss in the modules performance. Using the EL images, the predominant PV module failure for m-Si is the micro crack defect. However, TF PV module, a so-called white spot has been noticed. This work provides new information on the degradation issue of various studied solar panels in desert conditions. Indeed, we have not identified such a study in this region despite the fact that the region has one of the best solar potential in the world with 4000 h of sunshine per year. In the full paper, degradation rates of more than 500 PV modules from both technologies and from 14 different manufacturers with various mounting type and exposed period will be presented. 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