Energetica India Magazine March - April 2026

MODULE RELIABILITY 61 energetica INDIA- Mar-Apr_2026 There is growing emphasis on sustainability, such as reducing carbon footprints, recycling of PV modules, and replacing tox - ic materials like lead in perovskites. The adoption of AI and IoT technologies is helping optimise manufacturing processes and system performance, while IoT enables real-time monitor - ing of solar farms. Other emerging technologies, such as quantum dot solar cells and organic PV, are still in early research stages but offer po- tential for ultra-low-cost and flexible applications in the future. Reliability of Modules For all types of PV modules, reliability remains the most crit- ical parameter. A PV module must perform for 25–30 years under open and often harsh environmental conditions, which vary significantly across different geographies. The module is expected to deliver the rated power with limited degradation throughout its service life. Even small reductions in performance can result in significant losses in energy output and therefore in revenues. Modules are exposed to external conditions like wind, temperature fluctua - tions, and water, which can lead to performance degradation. Therefore, the design quality, manufacturing accuracy, and the Bill of Materials (BoM) play a vital role in determining the long-term performance of a solar module. With current technology, TOPCon cell-based modules can be made highly reliable, capable of delivering power with minimal degradation over 25 years or more. Module Design and Types Solar cells must be hermetically sealed and then interconnect- ed in series and parallel configurations to form a solar PV mod - ule. A single PV module, as a basic unit of power conversion, is expected to last at least 25 years in open environments. Most modules come with a warranty ensuring performance degrada- tion does not exceed specified limits over 25–30 years. There are primarily two types of modules: 1. Crystalline Silicon-Based Modules: These include multicrys- talline, PERC, TOPCon, bifacial, back-contact, and tandem cell-based modules. Currently, TOPCon cell-based modules are the most widely used. 2. Thin-Film Modules: These use a thin layer of semiconductor material on a glass substrate. Early versions, like amorphous silicon-based modules, were only warranted for 15 years. Now, HJT modules are more prevalent, combining crystalline silicon with thin-film layers. Tandem modules using perovskite cells also fall into this category. The fundamental design of any module aims to protect inter- nal cell components from environmental factors such as hu- midity, temperature, UV radiation, rain, and wind. Environmental Factors for Degradation Moisture is one of the most damaging elements for PV mod - ules. It can degrade conductive silicon deposits, thin oxide lay - ers, and other semiconductor layers, including poly or amor- phous films. Studies have shown that effects like snail trails, corrosion, and discolouration result primarily from moisture ingress. The quality of the backsheet and the effectiveness of sealing determine how resistant a module is to moisture penetration. Initially, backsheets were made with a Tedlar-Aluminium-Ted - lar (TAT) configuration. While this design was excellent for moisture resistance due to the aluminium layer, it became less popular because: 1. Aluminium is conductive, making it unsuitable for high-watt- age modules used in large-scale solar farms. 2. Although aluminium offers perfect moisture barrier proper- ties, the added cost made it commercially less viable. As the industry pushed for cost reduction, the use of less con- forming (and sometimes less reliable) backsheets became more common. However, in large solar farms where performance guarantees are critical, the choice of a high-quality backsheet remains an important decision. Reliability Certification Various international standards like IEC, UL, and JIS are de - signed to provide third-party certifications regarding the use - ful life of PV modules. These tests are conducted in laboratory conditions over limited timeframes and then extrapolated to predict long-term performance. However, it’s important to un - derstand that these certifications do not guarantee actual field performance over 25–30 years. Modules in the real world are exposed to a combination of stress factors – temperature, humidity, UV radiation, wind, and light – which change over time. Manufacturer reliability labs often conduct Design of Experiments (DoE) under fixed conditions to test module durability under combined stress sce- narios. Such testing helps in estimating the real-world life and perfor- mance variation of PV modules made from different materials and technologies. In this context, the backsheet remains one of the most crucial components to monitor and evaluate.