Performance Degradation Of Photovoltaic Modules Research Articles

A field-function methodology predicting the service lifetime of photovoltaic modules

The service lifetime of photovoltaic (PV) modules is an essential basis for the business investment and operation in PV power generation systems, with continuous distribution in specific geographical areas. To accurately predict the service lifetime of PV modules operated at a specific location, a continuous quantitative field-function methodology based on geographical clustering of influencing factors is proposed in this research. Firstly, failure mode and effects analysis technology is applied to systematically analyze the relevant factors affecting the performance degradation of PV modules, where eight key factors are extracted and quantitatively described. Secondly, the fuzzy c-means algorithm clusters the geographical regions to identify the areas with continuously distributed service lifetimes of PV modules. Finally, the continuous quantitative field-function model with latitude and longitude as variables is designed to describe each clustering category's service lifetime distribution characteristics. The model uses Pearson correlation coefficient to quantitatively describe the differences in performance degradation influencing factors at different latitude and longitude positions, and the model parameters are determined by fitting analysis of the known service life data of PV modules at specific latitude and longitude positions. Based on this model, the PV module field degradation rates in Guangzhou, Shenzhen, and Zhuhai in mainland China are estimated with relative errors to be 3.7149 %, 8.1525 %, and 6.6753 %, respectively. Compared to the existing approach, not only are the relative errors reduced by 1.4783 %, 5.1455 %, and 4.485 %, but the variations of service lifetime with geographic latitude and longitude are also visually and clearly described.

A method for accurately assessing field performance degradation of PV modules in different geographical regions

Solar photovoltaic (PV) technologies have developed rapidly in recent years. As the core part of PV system, performance of PV modules largely determines the output of PV system. Module performance gradually degrades during operation, and the degradation is generally variant at different sites due to the differences in climatic stresses. Thus, it is necessary for sites selection of PV power stations and investment decisions to accurately assess field degradation of modules in different locations. In this work, an approach to assess and predict module field degradation in different regions through mathematical modeling and regional clustering was introduced. First, a mathematical model describing the relationship between climatic stresses and module performance degradation was established using cumulative damage model. Moreover, considering geographical region attribute of model parameters, a scientific method, namely regional clustering based on climatic stressors, was further developed to predict the module degradation at different locations, which guarantees its prediction accuracy. Compared to existing approach, cumulative fitting deviation of estimated degradation rates obtained by this model was reduced by 23.46%. Meanwhile, relative deviation of estimated degradation rates in different places was reduced to 1.61% and 0.4% with instruction of regional clustering result, which validated the effectiveness of the overall method.

The impact of static wind load on the mechanical integrity of different commercially available mono‐crystalline photovoltaic modules

AbstractMechanical integrity of Photovoltaic (PV) modules, which is dependent upon the materials used and the manufacturing process, plays an important role in their performance and electrical output. Besides, the mechanical integrity of the modules is also affected by environmental conditions. Mechanical loads, which include loads produced by wind, snow, rain, and hail, tend to degrade the performance of the PV module by generating stresses and enhancing micro cracks and defects. This research aims to investigate the impact of wind loads on the performance degradation of PV modules. The overall objective was to investigate the reliability of modules available in Pakistan. Wind loads were simulated through an indigenously developed setup which allowed application of uniform load of 2400 Pa on the modules as per international standards (IEC 61215 and ASTM E1830‐15). A total of 12 PV modules, from three different vendors, each of 50 W rated power, were subjected to solar flash testing and electroluminescence imaging before and after the application of three cycles of mechanical load test. Greatest effect of wind loads was observed for modules which had defects present prior to the application of load. A maximum drop of 3.19% in the power output and 8.24% increase in the series resistance was observed. The results highlight that wind load has the ability to initiate cracks, propagate the pre‐existing ones as well as damage the grid fingers.

Evaluation of the electrical performance of a photovoltaic thermal system using nano-enhanced paraffin and nanofluids

Performance degradation of photovoltaic modules occurs when cell temperature increases; this is due to losses within the cell and the effect of surrounding weather as well. An increase in cell temperature leads to a decrease in the open-circuit voltage and hence, the electrical power produced by the PV. A nanofluid and nano-PCM (paraffin wax) -based PV/T hybrid collector has been employed in this paper. The experiments focus on the electrical performance and characteristics of the PV module under the weather conditions of Bangi-Malaysia. The cooling technique used is attaching the module to a nano-PCM tank and running nanofluids within. The results from the experimental tests show a maximum PV efficiency of 13.7% under operation for PV/T collector as appose to conventional PV module, which achieved an efficiency of 7.1%, which is suitable relative to the efficiency of 14% under standard testing conditions.

Reliability Study of c-Si PV Module Mounted on a Concrete Slab by Thermal Cycling Using Electroluminescence Scanning: Application in Future Solar Roadways

Several tests were conducted to ratify the reliability and durability of the solar photovoltaic (PV) devices before deployment in the real field (non-ideal conditions). In the real field, the temperature of the PV modules was varied during the day and night. Nowadays, people have been bearing in mind the deployment of PV modules on concrete roads to make use of the space accessible on roads. In this regard, a comparative study on the failure and degradation behaviors of crystalline Si PV modules with and without a concrete slab was executed via a thermal cycling stress test. The impact of the concrete slab on the performance degradation of PV modules was evaluated. Electroluminescence (EL) results showed that the defect due to thermal cycling (TC) stress was reduced in the PV module with a concrete slab. The power loss due to the thermal cycling was reduced by approximately 1% using a concrete slab for 200 cycles. The Rsh value was reduced to approximately 91% and 71% after thermal cycling of 200 cycles for reference PV modules, respectively. The value of I0 was increased to approximately 3.1 and 2.9 times the initial value for the PV modules without and with concrete, respectively.

Unveiling the Failure Mechanism of Electrical Interconnection in Thermal-Aged PV Modules

The electrical interconnection is the most decisive current transportation pathway in photovoltaic (PV) modules. However, thermal stresses, induced by temperature variation, can reduce the mechanical properties of the electrical interconnection and lead to the performance degradation of PV modules. The present study aims to investigate the influence of thermal stress on the failure mechanism of the electrical interconnection. The mechanical integrity of current transmission layers and interfaces is measured by peeling tests and evolution of defects and failure process is observed by in-situ electroluminescence (EL) imaging and scanning electron microscopy (SEM). Under repeated thermal stress, the defects initiated at the end of the soldering track and, then, expanded to the adjacent cell regions. Initially, the silver-glass interface was more vulnerable to separation under the action of the peeling force. However, the disruption between the silver busbar and silicon wafer increased with increasing thermal cycling. In addition, a possible failure mechanism has been proposed for electrical interconnection by SEM observation and defect analysis. Lastly, we have demonstrated that the reliability of the interconnection structure can be improved by increasing the edge distance of the PV modules or using an anti-overpressure device.

Description of performance degradation of photovoltaic modules using spectral mismatch correction factor under different irradiance levels

Outdoor short-circuit current (ISC) of test photovoltaic (PV) modules, i.e., (1) multi-crystalline silicon, (2) heterostructure-with-intrinsic-thin-layer, (3) single-crystalline silicon back-contact, (4) CuInSe2, and (5) CdTe modules, was evaluated using single-crystalline silicon (sc-Si) PV module as PV module irradiance (Irr) sensor (PVMS). PVMS is used to estimate simultaneous Irr and spectral mismatch correction factor (MMPVMS). The measured ISC (ISC-meas) of the test PV modules at outdoor location under various conditions was corrected to the ISC under standard test condition (STC) for the corrected ISC (ISC-corrected) using the MMPVMS and simultaneous Irr, yielding the description of the degradation of the test PV modules for the credibility of their fabrication technology. Moreover, the estimation of ISC-corrected of the test PV modules under different Irr levels was performed. The ISC-corrected with high precision, close to ISC under STC, was obtained under Irr level of ≥0.2 sun, observed by the PVMS. This leads to the increase the investigation opportunity on both sunny day and cloudy day. The ISC-corrected with the highest precision is moreover obtained under Irr level of ≥0.7 sun. The method using the simultaneous Irr and MMPVMS observed by the PVMS could be applicable under the large fluctuation of the Irr levels.

The effect of dust with different morphologies on the performance degradation of photovoltaic modules

This research investigated the effect of dust with different morphologies on the performance degradation of various photovoltaic (PV) technologies consisting of polycrystalline silicon (pc-Si), mono-crystalline silicon (mc-Si), and amorphous silicon (a-Si). Dust collected from two different locations, Babuin, Indonesia and Perth, Australia, was coated artificially onto the surface of glass of the PV modules. The analysis revealed that dust from Babuin was dominated by larger size and porous particles so that it passed more light than ones from Perth. Dust from Perth with angular and diagonal shapes had better optical property than that from Babuin featuring elliptical and spheroid particles. As a result, transmittance values of the two types of dust tend to balance out. For an equivalent amount, the effect of dust from Babuin and Perth on the performance degradation of each PV technology was similar. Furthermore, transmittance spectral curves of the two types of dust were fairly flat with respect to the wavelength range of pc-Si, a-Si, and mc-Si technologies. Consequently, dust from either Babuin or Perth have similar effects on the three PV technologies.

Performance degradation of photovoltaic modules at different sites

In this work are presented results of electrical performance measurements of 120 crystalline silicon PV modules following long-term outdoor measurements. A set of 90 PV modules represent the first grid-connected photovoltaic (PV) system in Algeria, installed at the level of the “Centre de Développement des Energies Renouvelables” (CDER) site (Mediterranean coast), Bouzareah. The other 30 PV modules were undertaken in an arid area of the desert region of Ghardaïa site, about 600 km south of Algiers, with measurements collected from different applications. Following different characterization tests, we noticed that the all tested PV modules kept their power-generating rate except a slight reduction. Therefore, a mathematical model has been used to carry out PV module testing at different irradiance and temperature levels. Hence, different PV module parameters have been calculated from the recorded values of the open-circuit voltage, the short-circuit current, the voltage and current at maximum power point. The electrical measurements have indicated different degradations of current-voltage parameters. All the PV modules stated a decrease in the nominal power, which is variable from one module to another.

Evaluating the reliability of crystalline silicon photovoltaic modules in harsh environment

Electricity generated using photovoltaic system can only be commercial if the photovoltaic modules operate reliably for 20–25 years under field conditions. Understanding the performance degradation of photovoltaic modules is critical for optimizing its financial viability. Performance degradation of photovoltaic modules is due to multiple factors such as installation site and module technologies. In order to gain insight on performance degradation of crystalline silicon PV technology in harsh environment, a degradation effects study of c-Si photovoltaic modules in desert environment was carried. The main contribution of this paper is focused on the evaluation of c-Si PV modules performance that operated in extreme environmental conditions. This evaluation usually consists of I-V curve field measurements and visual inspections.

The contribution of dust to performance degradation of PV modules in a temperate climate zone

This research investigates the contribution of dust to the long-term performance degradation of various photovoltaic (PV) modules that have been operating for almost eighteen years without any cleaning procedures at the Renewable Energy Outdoor Testing Area (ROTA), Murdoch University, Perth, Australia. A solar module analyser was used to assess the PVs’ electrical performance, while a combination of spectrophotometer, scanning electron microscope, electron dispersive spectroscope and X-ray diffraction were used to exam the properties of the dust on the panels. The study found that the degradation of the PV modules’ power output, ranged from 19% to 33%. The degradation is mostly due to non-dust related factors such as corrosion, delamination, and discoloration, which account about 71–84%, although the contribution of dust is still significant at 16–29%. Anova analysis shows that the dust has a fairly uniform impact on the performance degradation of all PV technologies at ROTA. This is in line with the results of spectral transmittance curves for different dust density samples that essentially flat over the wavelength range of the PV modules. An investigation of the properties of dust revealed that dust particles deposited on PV modules’ surface at ROTA were dominated by fine particles built of large amounts of quartz (SiO2), followed by calcium oxide (CaO) and some minors of feldspars minerals (KAlSi3O8), which are the main factors in transmittance losses that affect PV module performance.

Assessing the early degradation of photovoltaic modules performance in the Saharan region

In this study, the electrical performance degradation of photovoltaic modules (UDTS-50) functioning for a period of 11years in a region of the Sahara (URER-MS ADRAR) is analyzed. This paper is devoted to an experimental study of current–voltage characteristics of several PV modules exposed to the extreme weather conditions in desert area. The electrical performance degradation and failure modes are estimated from series of current–voltage characteristics performed in the field. Experimental results show that some PV modules degrade up to 12% compared to their initial state. The performance analysis of the others tested modules revealed some defects, such as cracked cells and physical material defects. The identification of the origin of degradation and failure modes and how they affect the photovoltaic modules is necessary to improve the reliability of photovoltaic installations.

Degradation evaluation of crystalline-silicon photovoltaic modules after a few operation years in a tropical environment

This paper presents an evaluation of the performance degradation of Photovoltaic modules after few operation years in a tropical environment. To this end, the International Center for Research and Training in solar energy at Dakar University and the Lasquo-ISTIA laboratory of Angers University have put in place a research project in order to investigate the impact of the tropical climatic conditions on the PV modules characteristics. Accordingly, two monocrystalline-silicon (mc-Si) PV modules and two polycrystalline- silicon (pc-Si) PV modules are installed at Dakar in Senegal and monitored during a few operation years: Module A (16 months), Module B (41 months), Module C (48 months) and Module D (48 months). After few operation years under tropical environment, the global degradation and the degradation rate of electrical characteristics such as I-V and P-V curves, open-circuit voltage (Voc), short-circuit current (Isc), maximum ouput current (Imax), maximum output voltage (Vmax), maximum power output (Pmax) and fill factor (FF) are evaluate at standard test conditions (STC). This study reports on data collected from 4 distinct mono- and poly-crystalline modules deployed at Dakar University in Senegal. The study has shown that Pmax, Imax, Isc and FF are the most degraded performance characteristics for all PV modules. The maximum power output (Pmax) presents the highest loss that can be from 0.22%/year to 2.96%/year. However, the open-circuit voltage (Voc) is not degraded after these few exposition years for all studied PV modules.