Impact resistance of BIPV systems: New testing procedure for performance assessment of multifunctional products

Abstract Building integrated photovoltaics (BIPV) is progressively achieving an advanced level of technical maturity and considerable market penetration. In the last kilometre for considerable market implementation, major challenges are today mostly related to improving cost‐effectiveness and product reliability. BIPV multifunctional products are still framed in complex and sometimes unclear qualification processes, in the grey area between electrotechnical and construction sectors, impacting commercialization and users' confidence. The EN 50583 part 1 and part 2 standards today represent the main regulatory framework in Europe for BIPV. However, acts in force for product certification, in the construction and electrical sectors, in most national and local contexts are not yet harmonized for BIPV and imply wide margins of interpretation. The product's qualification in the EU is therefore based on electrical standards for photovoltaics modules or, on the other hand, on standards for construction products. To overcome some of these barriers and challenges, the authors propose a newly developed procedure for testing the impact resistance of BIPV products, introducing a performance‐based approach with the goal of combining building and electrical‐related limit states and responding to the need for a harmonized assessment to ensure the product's safety in use. The methodology and preliminary findings resulting from the application of real test cases, taking also into account the effect of temperature, are presented and analysed. As a result, it is envisaged that the implementation will help operators and prospective normative upgrades, ensuring more outstanding product quality for BIPV's market and driving towards a drop in life cycle costs

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

The 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

35 years of photovoltaics: Analysis of the TISO‐10‐kW solar plant, lessons learnt in safety and performance—Part 1

The TISO‐10‐kW solar plant, connected to the grid in 1982, is the oldest installation of this kind in Europe. Its history is well documented, and the full set of modules has been tested indoors at regular intervals over the years. After 35 years of operation, we observe an increase in the degradation rates and that the distributions of modules' performances are drastically changing compared with previous years. Two groups of modules can be observed: (a) group 1: 21.5% of the modules show a very modest degradation, described by a Gaussian distribution with mean yearly power degradation of only −0.2%/y. (b) Group 2: 72.9% of the modules form a negatively skewed distribution with a long tail described by mode (−0.54%/y), median (−0.62%/y), and mean (−0.69%/y) values. In earlier years, decreases in performances could strongly be correlated to losses in fill factor (FF). After 35 years, the situation changes and, for a subset of modules, losses in the current (Isc) are superimposed to losses in FF. The reasons for this will become clearer in part 2, where we will present results of a detailed visual inspection on the whole set of modules and will focus on safety aspect too. We conclude that, after 35 years of operation in a temperate climate, approximately 60% (~70% if considering a ± 3% measurement uncertainty) of the modules would still satisfy a warranty criteria that module manufacturers are presently considering to apply to the technology of tomorrow: 35 years of operation with a performance threshold set at 80% of the initial value.JRC.C.2-Energy Efficiency and Renewable

Analysis of Non-Linear Long-Term Degradation of PV Systems

The current work presents the degradation evaluation of different PV systems under the weather conditions prevailed in the Swiss midlands, Jura and Alps. The purpose of this paper is to analyze degradation rates and change of degradation rates over time. The analysis is done for the degradation rates of three 25-30 years old PV systems in Switzerland, one of which is the oldest grid connected PV system in Europe of its size (30-year-old 555 kW PV system Mont-Soleil). The two other PV systems are located on Jungfraujoch and in Burgdorf. The examined degradation metric in this study is the performance ratio (PR) which is normalized energy yield with received insolation. The focus of this study is to examine the linear degradation rate of the PV plants and find the best non-linear fitting functions to the degradation. It is found that the annual degradation differs between the systems although they have identical PV modules. The highest linear degradation was found for Tiergarten East system with 0.6 %, 0.5 % for Tiergarten West, 0.3 % for Mont-Soleil and 0.02 %, for the Junfraujoch system. For non-linear degradation, 2nd order polynomial and breakpoint functions were used. The performance of both functions varies depending on to the PV system, and it is found that breakpoint function provided the best results and fit better than polynomial function

35 years of photovoltaics: Analysis of the TISO-10-kW solar plant, lessons learnt in safety and performance-Part 1

The TISO-10-kW solar plant, connected to the grid in 1982, is the oldest installation of this kind in Europe. Its history is well documented, and the full set of modules has been tested indoors at regular intervals over the years. After 35 years of operation, we observe an increase in the degradation rates and that the distributions of modules' performances are drastically changing compared with previous years. Two groups of modules can be observed: (a) group 1: 21.5% of the modules show a very modest degradation, described by a Gaussian distribution with mean yearly power degradation of only -0.2%/y. (b) Group 2: 72.9% of the modules form a negatively skewed distribution with a long tail described by mode (-0.54%/y), median (-0.62%/y), and mean (-0.69%/y) values. In earlier years, decreases in performances could strongly be correlated to losses in fill factor (FF). After 35 years, the situation changes and, for a subset of modules, losses in the current (Isc) are superimposed to losses in FF. The reasons for this will become clearer in part 2, where we will present results of a detailed visual inspection on the whole set of modules and will focus on safety aspect too. We conclude that, after 35 years of operation in a temperate climate, approximately 60% (similar to 70% if considering a +/- 3% measurement uncertainty) of the modules would still satisfy a warranty criteria that module manufacturers are presently considering to apply to the technology of tomorrow: 35 years of operation with a performance threshold set at 80% of the initial value