Degradation Rate Of Modules Research Articles

Measurement and validation of polysilicon photovoltaic module degradation rates over five years of field exposure in Oman

<abstract> <p>Degradation of PV modules have a severe impact on its power-producing capabilities thus affecting the reliability, performance over the long run. To understand the PV degradation happening under the influence of local environmental conditions a survey was conducted on six polycrystalline silicon-based PV modules over five years. It has been observed that the average degradation rates stood at 1.02%/year at irradiances 800 W/m<sup>2</sup> and 0.99%/year at irradiances 600 W/m<sup>2</sup>, which are almost double the manufacturer proposed values. Upon further investigations, it has been found that discoloration of encapsulant in modules 3, 5, and 6 have been the main factor causing the reduction of the short circuit current (I<sub>sc</sub>) thus affecting the overall power production capacity of the installed PV system. Considering the amount of time, resources and manpower invested to perform this survey an alternate way of estimating the PV degradation rates is also investigated. The exponential decay factor-based model is adopted to correlate the encapsulant discoloration seen on-site in the form of a mathematical equation to predict the current loss. This loss is defined as the visual loss factor in this paper. Further, the output I-V curves are simulated using MATLAB Simulink-based mathematical model which also integrates visual loss factor (VLF) losses into it. Such simulated I-V curves have shown a good match with the measured I-V curves at the same irradiance with an error less than 3%. Authors anticipate that this modelling approach can open the door for further research in developing algorithms that can simulate the PV degradation rates.</p> </abstract>

Hardware System for Parallel Processing of Flash Memory Chips for Preparing an Identification System

Research subject. The paper presents options for the implementation of a hardware-software system for parallel processing of flash memory chips for preparing an identification system. Method. The analy-sis of the degradation rate of memory modules is carried out and the average values of the processing time and the number of processing cycles for one memory chip during the preparation of the identifier are determined. Core results. Parallel and serial-parallel schemes for flash memory chips processing are proposed. Practical relevance. It is proposed to use the developed complex for the creation of identifying flash memory microcircuits intended for statistical research of identification methods and pro-tocols.

Analysis of long-term performance and reliability of PV modules under tropical climatic conditions in sub-Saharan

Reliability assessment of Photovoltaic (PV) modules is very crucial to increase the service lifetime of PV systems. This study assesses the degradation rate and reliability of PV modules operated for twelve years under the tropical climatic condition in sub-Saharan. For this purpose, various characterization techniques, namely visual inspection, infrared (IR) thermography assessment, and current-voltage (I-V) characterization, have been employed to evaluate the performance of PV modules. Moreover, the functioning of bypass diodes has been tested under partial shading situations. The results demonstrate that after twelve years of outdoor operation, the short-circuit current (Isc) of modules have been degraded up to 16.4% with an average decrease of 11.7% compared to the nameplate values. The open-circuit voltages (Voc) were reduced from 11.4% to 17.1% with a mean of 14.8%. The decline in Fill Factor (FF) of the modules ranges from 11.3% to 24.2%, and the losses of power output were between 34.5% and 41.4%. Moreover, the visual and thermography assessment reveals that the PV modules are severely affected by various failures such as EVA browning, cell interconnects ribbons browning and the corrosion of solder bonds. The results show that averagely, the FF is the most significant factor influencing the loss in the power output of the modules.

Corrosion growth of solar cells in modules after 15 years of operation

This paper is to study the deterioration of PV modules after 15 years of operation in Thailand. All 16 modules of a string were annually measured in the standard testing laboratory, then taken back to the same position of string since the 7th year after operation. The results and data analysis can be divided into 3 parts consisting of electrical performance evaluation, physical deterioration observation, and corrosion growth on cell ribbons. From the electrical results of performance at STC, it was found that power of modules were less than 80% of the nameplate value in the 15th year for 75% of total modules. The average degradation rates, based on nameplate, was 1.47%/year. The degradation rates of modules since the 10th year after operation were in the range of 2.5 to 3.0%. From the visual failures on the front and rear side of modules were appeared in all modules. During the 12th – 15th year, the corrosion area growth on cell ribbons, calculated by ImageJ program, was around 10–17%/3 years of ribbons area, especially for cells beside junction box. The colors of corrosion products were also observed in both color appearance and color change on each cell of selected modules. For these modules, we intend to continue operation until end-of-life of the system. Another similar module was destructed and taken to investigate. The corrosion products and color of corrosion products can be justified by EDS and referred to ASTM D130 standard. Sn and Pb corrosion products were confirmed by SEM and EDS.

Mathematical model on the integration of renewable energy in the mining industry

Purpose Priorities of decarbonizing the mining sector together with an availability of cost-effective technological solutions lead renewable energy (RE) to become an attractive energy source for the mining industry. Several pilot projects are run as hybrid systems, providing additional capacity to traditional energy systems. The purpose of this paper is to develop a mathematical model as a decision-making tool. The decision refers to a replacement of the fossil fuel system contains by the hybrid system in the sense of no return. Design/methodology/approach Four systems are considered. System one contains only a diesel plant. System two consists of a hybrid energy system with a photovoltaic (PV) part and a genset as back-up. System three includes a conventional natural gas combined cycle (CGCC) plant. Finally, system four covers a hybrid energy system with a PV part and CGCC turbine. The mathematical model is based upon the well-known concept of levelized cost of electricity. Findings The scenarios account for the degradation rate of PV modules, the PV yields of mines in different locations and the greenhouse gas emissions impact. The results show the break-even times of each scenario and the years of no return for the four systems in each scenario. Research limitations/implications The solution of the model is performed for two case-studies. Case study 1 compares the diesel and hybrid PV-diesel systems. Case study 2 compares the CGCC and hybrid PV-natural gas systems. Practical implications This model can be generalized to all mining settings, with specific practical implications for off-grid mines. Social implications The results of this paper bring a valuable contribution to carbon dioxide emissions reduction. Originality/value The paper aims to enhance the attention of decision-makers on fossil fuel and RE technologies increase the attractiveness of RE in powering mining operations.

Global Climate Data Processing and Mapping of Degradation Mechanisms and Degradation Rates of PV Modules

Photovoltaic (PV) systems are the cheapest source of electricity in sunny locations and nearly all European countries. However, the fast deployment of PV systems around the world is bringing uncertainty to the PV community in terms of the reliability and long-term performance of PV modules under different climatic stresses, such as irradiation, temperature changes, and humidity. Methodologies and models to estimate the annual degradation rates of PV modules have been studied in the past, yet, an evaluation of the issue at global scale has not been addressed so far. Hereby, we process the ERA5 climate re-analysis dataset to extract and model the climatic stresses necessary for the calculation of degradation rates. These stresses are then applied to evaluate three degradation mechanisms (hydrolysis-degradation, thermomechanical-degradation, and photo- degradation) and the total degradation rate of PV modules due to the combination of temperature, humidity, and ultraviolet irradiation. Further on, spatial distribution of the degradation rates worldwide is computed and discussed proving direct correlation with the Köppen-Geiger-Photovoltaic climate zones, showing that the typical value considered for the degradation rate on PV design and manufacturer warranties (i.e., 0.5%/a) can vary ± 0.3%/a in the temperate zones of Europe and rise up to 1.5%/a globally. The mapping of degradation mechanisms and total degradation rates is provided for a monocrystalline silicon PV module. Additionally, we analyze the temporal evolution of degradation rates, where a global degradation rate is introduced and its dependence on global ambient temperature demonstrated. Finally, the categorization of degradation rates is made for Europe and worldwide to facilitate the understanding of the climatic stresses.

35 years of photovoltaics: Analysis of the TISO‐10‐kW solar plant, lessons learnt in safety and performance—Part 2

AbstractThe TISO‐10‐kW plant, installed in Lugano (Switzerland) in 1982, is the first grid‐connected PV plant in Europe. In a joint publication (part 1), we presented the results of the electrical characterization performed in 2017—after 35 years of operation—of the 288 Arco Solar modules constituting the plant. Power degradation rates were different among modules and two groups could clearly be distinguished: group 1, with a remarkably low mean degradation rate of −0.2% per year, and group 2, with a mean degradation of −0.69% per year. After 35 in a temperate climate, approximately 70% of the modules (considering a ±3% measurement uncertainty) still exhibit a performance higher than 80% of their initial value. In this paper, when possible, we attempt at correlating module performance losses to specific failure mechanisms. For this sake, an extensive characterization of the modules was performed using visual inspection, IV curve measurements, electroluminescence, and infrared imaging. We remarkably find that module degradation rates are highly correlated to the aging pattern of the encapsulants used in module manufacturing. In particular, a specific formulation of the encapsulant (PVB), which was used only in a minority of the modules (approximately 10%), leads to degradation rates of −0.2% per year, which corresponds to a loss in performance below 10% over 35 years. Potential safety threats are also investigated, by measuring the frame continuity, the functionality of the bypass diodes, and the module insulation. Finally, we discuss how the analysis of a 35‐year‐old PV module technology could benefit the industry in order to target PV module lifetimes of 40+ years.

Investigation on Potential-Induced Degradation in a 50 MWp Crystalline Silicon Photovoltaic Power Plant

The regular performance deterioration of P-type crystalline silicon solar modules and module strings caused by potential-induced degradation in a photovoltaic power plant was found in the field. The PID-affected solar modules dismounted from the photovoltaic power plant were further investigated systematically in the laboratory. For the first time, we found that the neutral point of voltage in a module string moved forward to the positive pole for a PID-affected module string as time goes on. Even if low positive voltage is applied to a PID-prone module, it could cause PID. The thermographic and electroluminescence (EL) images of a PID-affected module string also exhibit a regular degradation pattern. This is in good agreement with the measured power loss of the dismounted solar modules under standard test conditions. The results obtained in this paper show that the maximum power degradation rate of solar modules was as high as 53.26% after only one year of operation because of PID in the field. Due to the vast amount of solar modules and incomplete recovery, this is a terrible catastrophe for the owner of a power plant and module producer.

Long-term performance and degradation rate analyses of photovoltaic modules exposed in the Gobi Desert, Mongolia

Two types of crystalline silicon (c-Si) photovoltaic (PV) modules have been tested in the cold-dry climate of the Gobi Desert of Mongolia, from 2002 to 2012, to verify the preliminary estimation of PV power generation. This study mainly focuses on the analysis of the long-term performance of the PV modules using indices such as energy yield, reference yield, performance ratio (PR), and characterization indices of the main electrical parameters as well as degradation rate. Average annual energy yields were 1880 h for Module 1 and 1789 h for Module 2. Thus, PRs were 0.85 and 0.80, while the average annual reference yield was 2223 h. On the other hand, degradation rates of Modules 1 and 2 were −1.28 and −0.86%/year, respectively. The electrical degradation observed in both modules was due to the loss of short-circuit current as open-circuit voltage reduction was not considered in this field test.

Optimum inverter sizing of grid-connected photovoltaic systems based on energetic and economic considerations

The optimum sizing ratio of the photovoltaic (PV) array capacity, compared to the nominal inverter input capacity, was determined in grid-connected PV (GCPV) systems from two points of view: energetic and economic. The optimum ratio was determined by both empirical and analytical approaches, and based on two PV arrays connected to their inverters, plus three simulated inverters. The flatness of the optimum-energy region due to the inverter characteristics was decreased when economic factors were taken into account. The energetic and economic optimum sizing intervals were defined as the sizing regions causing less than 1% losses from their corresponding optimum points. Subsequently, a compound optimum sizing interval was proposed to maximise the energy injected to the grid and minimise economic costs simultaneously. The results showed that the GCPV system with lower specific DC power generation (kWDC/kWp) and inverter/module cost ratio presented a wider interval (1.12–1.25) than the interval (1.17–1.19) of the system with higher specific DC power generation and cost ratio, for all the analysed inverters. Finally, the optimum sizing ratio was completed by considering a PV module degradation rate of 1%/year, which resulted in a 10% increase in the optimum sizing ratio for a 20-year lifetime.

Annual degradation rates of recent crystalline silicon photovoltaic modules

AbstractLong‐term reliability and durability of recently installed photovoltaic (PV) systems are currently unclear because they have so far only been operated for short periods. Here, we investigated the quality of six types of recent crystalline silicon PV modules to study the viability of PV systems as dispersed power generation systems under operating conditions connected to an electric power grid. Three indicators were used to estimate the annual degradation rates of the various crystalline silicon PV modules: energy yield, performance ratio, and indoor power. Module performance was assessed both with indoor and outdoor measurements using electric measurements taken over a 3‐year period. The trends in the results of the three indicators were almost consistent with each other. Although the performance of the newly installed PV modules decreased by over 2% owing to initial light‐induced degradation immediately after installation, little to no degradation was observed in all the PV modules composed of p‐type solar cells over a 3‐year operation period. However, the PV modules composed of n‐type solar cells clearly displayed performance degradation originating from the reduction of open‐circuit voltage or potential‐induced degradation. The results indicate that a more continuous and detailed outdoor actual investigation is important to study the quality of new, high‐efficiency solar cells, such as heterojunction, interdigitated back contact solar cells, and passivated emitter rear cells, which are set to dominate the PV markets in the future. © 2017 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd.

Experimental evaluation of the discoloration effect on PV-modules performance drop

The objective of this paper is to measure and evaluate the degradation impact on a photovoltaic (PV) module exposed for almost two years under Moroccan climate. This degradation is a discoloration spot observed above the module's junction box. For this purpose, the drop of the module's electrical performances has been firstly measured using the I-V tracer PVPM1000X and compared with the initial values given by the manufacturer. Afterwards, and in order to measure the direct effect of the detected discoloration on the power production, comparison between the outputs of the affected module and another one with the same characteristics (taken as reference) has been done. Results show that the module's degradation rate (from the initial state) is of 7.56 %/year. Moreover, the power difference between the affected modules and the one taken as reference was found to be of 13.2 watts in average. Generally, this difference is directly linked to the detected discoloration and it represents a power drop of 5.28% from the module's initial capacity.

Degradation analysis of photovoltaic modules under tropical climatic conditions and its impacts on LCOE

After 4 years of operation at Thailand Science Park, degradation analysis of 73 photovoltaic (PV) modules of four different PV technologies; multi c-Si, hetero-junction Si, micromorph and CIGS, has been carried out. The degradation rate (DR) of individual modules and array performance are presented. It was found that some micromorph (thin film Si 1) modules seriously degraded and were in failure mode, resulting in a severe degradation of the thin Si 1 array’s performance. The average DR of other PV modules was found to range between 0.3 and 1.9%/year. The standard deviation (SD) of data from modules in the same array indicates the level of mismatch, which plays a role in evaluating array’s performance. The levelized cost of electricity (LCOE) in this study was found to range between 4.1 and 14 baht/kWh, depending on PV technology and its DR. The results suggest that, without any reduction of costs, the LCOE of solar PV electricity in Thailand would possibly be comparable with the retail price when the present PV technology has DR of about 0.2%/year or lower. The database we obtained is informative and useful for a further study on PV reliability and cost of solar PV electricity in the tropics.

Degradation analysis of photovoltaic modules based on operational data: effects of seasonal pattern and sensor drifting

Degradation analysis of photovoltaic (PV) modules based on real operational data is essential to the future development of the PV industry. Weather conditions and system drifting often lead to large uncontrollable fluctuations in operational data, which present great challenges for calculating degradation rates of PV modules. In this paper, we propose a new numerical two-step approach to overcome these difficulties. In particular, we will show that our method is able to eliminate effects of seasonal patterns and systematic sensor drifting in evaluating degradation rates of PV modules. The method is applied to the six-year operational data of a solar PV system installed at CA United States. We demonstrate that our approach can greatly improve the degradation calculations, compared with other widely used methods.

Technology advances needed for photovoltaics to achieve widespread grid price parity

AbstractTo quantify the potential value of technological advances to the photovoltaics (PV) sector, this paper examines the impact of changes to key PV module and system parameters on the levelized cost of energy (LCOE). The parameters selected include module manufacturing cost, efficiency, degradation rate, and service lifetime. NREL's System Advisor Model (SAM) is used to calculate the lifecycle cost per kilowatt‐hour (kWh) for residential, commercial, and utility scale PV systems within the contiguous United States, with a focus on utility scale. Different technological pathways are illustrated that may achieve the Department of Energy's SunShot goal of PV electricity that is at grid price parity with conventional electricity sources. In addition, the impacts on the 2015 baseline LCOE due to changes to each parameter are shown. These results may be used to identify research directions with the greatest potential to impact the cost of PV electricity. Copyright © 2016 John Wiley & Sons, Ltd.

Assessment of PV Modules Degradation based on Performances and Visual Inspection in Algerian Sahara

On-site measurement is a useful mean of diagnostic value and an important key for the assessment of electrical performances and the study of degradation of photovoltaic modules. This paper presents some findings of PV modules behaviour in Adrar (southernmost of Algeria). The study allowed assessing the long-term degradation of modules and detecting possibly defects by visual inspection method. The average annual power degradation rate of PV modules is around 1,5%. Such value tallies with several studies. The visual inspection let us to detect many types of failures in PV modules like delamination, burn marks, cracking but discoloration of encapsulant was the predominant modes of degradation. This study will provide useful information to the manufacturers and owners and helps to better understanding the degradation mechanisms and, therefore, improving the long-term reliability of photovoltaic modules in the Algerian Sahara.

Performance Degradation of Various PV Module Technologies in Tropical Singapore

The performance of ten photovoltaic (PV) modules with nine different solar cell technologies (and one different module construction) is monitored in the tropical climate of Singapore. The types of modules included in this study are monocrystalline Si (glass-backsheet with frame and glass-glass without frame), heterojunction crystalline Si, monocrystalline Si back-contact, multicrystalline Si, double-junction “micromorph” Si, single-junction/double-junction amorphous Si, CdTe, and CIGS. Three years of outdoor monitoring data are used to extract degradation trends of the performance of the various modules. Statistical decomposition methods are used to extract trends for performance ratio (PR), short-circuit current (I SC ), open-circuit voltage (V OC ), and fill factor (FF). The degradation rates of the monocrystalline Si modules are found to be equal to or less than -0.8% per year, mainly contributed by the decrease in I SC . The multicrystalline Si module shows a slightly higher degradation rate of -1.0% per year. The amorphous Si, micromorph Si, and CdTe modules show degradation rates of around -2% per year. The CIGS module showed an exceptionally high degradation rate of -6% per year. The decrease in FF and VOC is found to be significant for all the thin-film modules but not for the crystalline silicon modules.

Multi‐pronged analysis of degradation rates of photovoltaic modules and arrays deployed in Florida

ABSTRACTThe long‐term performance and reliability of photovoltaic (PV) modules and systems are critical metrics for the economic viability of PV as a power source. In this study, the power degradation rates of two identical PV systems deployed in Florida are quantified using the Performance Ratio analytical technique and the translation of power output to an alternative reporting condition of 1000 W m−2 irradiance and cell temperature of 50 °C. We introduce a multi‐pronged strategy for quantifying the degradation rates of PV modules and arrays using archived data. This multi‐pronged approach utilizes nearby weather stations to validate and, if needed, correct suspect environmental data that can be a problem when sensor calibrations may have drifted. Recent field measurements, including I‐V curve measurements of the arrays, visual inspection, and infrared imaging, are then used to further investigate the performance of these systems. Finally, the degradation rates and calculated uncertainties are reported for both systems using the methods described previously. Copyright © 2012 John Wiley & Sons, Ltd.