> Quick answer: Long-term reliability in outdoor solar products is most strongly correlated with consistent material sourcing, robust encapsulation, and rigorous environmental stress testing—practices that ensure durability under real-world conditions [1][20].
Ensuring long-term reliability in outdoor solar products like solar lamps is crucial for their performance and longevity. This article delves into the key production-line practices that can significantly impact the reliability of these products, including rigorous material selection, process control, and environmental stress testing.
The Role of Encapsulation Integrity and Material Durability
The failure of perovskite solar cells due to water exposure underscores the critical need for proper encapsulation [8][9]. Similarly, high-efficiency technologies such as TOPCon and heterojunction modules can be severely affected by UV exposure, indicating that encapsulation and UV resistance are essential [6].
- Proper Encapsulation: Ensures protection against environmental ingress.
- UV Resistance: Essential for preventing degradation over time.
Consistent Material Sourcing and Process Control
A study by RETC found that differences in glass suppliers can lead to an order-of-magnitude difference in glass fracture rates, despite identical designs [16]. This highlights the importance of consistent material quality and traceability.
- Material Traceability: Ensures uniformity across production batches.
- Lot Testing: Validates the reliability of each batch.
Environmental Stress Testing
UL and other organizations emphasize the need for accelerated aging tests such as damp heat, thermal cycling, and UV exposure to screen for long-term degradation [1][4][20].
| Test Type | Purpose |
|–––––––-|–––––––––-|
| Damp Heat | Moisture resistance |
| Thermal Cycling | Temperature stability |
| UV Exposure | Light-induced degradation |
System-Level Quality Assurance
The failure of connectors due to moisture ingress and poor mating is often linked to supply chain pressures [2]. Ensuring consistent, traceable processes across the entire system is essential for reliability.
- Connector Integrity: Prevents moisture ingress.
- Supply Chain Oversight: Maintains material quality.
Data-Driven Monitoring and Field Validation
Tigo Energy and SolarEdge advocate for IoT integration to translate material quality and field behavior into predictable long-term performance [17]. Intertek’s on-site testing services use mobile labs and drones to detect underperformance without shipping modules, enabling faster reliability assessments [11].
Innovation vs. Reliability
Despite the industry’s focus on efficiency, reliability is increasingly tied to disciplined manufacturing practices rather than technological innovation alone. New technologies like n-type cells and perovskite materials are more sensitive to environmental stressors, making their reliability even more dependent on robust encapsulation and process control [6][8].
Key Takeaways
- Robust encapsulation and material durability are critical for preventing degradation.
- Consistent material sourcing and rigorous testing ensure uniform performance across batches.
- System-level quality assurance extends beyond the module to include connectors and supply chain oversight.
- Data-driven monitoring and field validation enhance reliability through continuous improvement.
References
- [1] UL_White_Paper_Getting_More_Reliability_in_PV_Installations__b6861436 — magazine
source passage
proven scientific test procedures to screen PV modules for reliability, performance and safety. UL’s performance and reliability services for PV modules provide third-party evidence of industry standard testing to assess consistency in the manufacturing process that also includes technical inspections of PV module factory operations. Additional tests can be conducted to demonstrate the impact of long-terms stresses on PV module performance and safety. 1 “Development and application of a UV light source for PV-module testing,” M. Koehl, et al, 24th European Photovoltaic Solar Energy Conference (2009). Web. 8 April 2014. http://www.eupvsec-proceedings.com/roceedings?paper=4697. 2 “Reliability of PV-modules – Natural, accelerated and simulated degradation,” M. Koehl, et al, SPIE Conference 7048-4, September 2008. Web. 8 April 2014. http://www.iea-pvps.org/index.php?id=15&eID=dam_frontend_push&docID=272. 3 “System voltage potential-induced degradation mechanisms in PV Modules and Methods for Test,” P. Hacke, et al, 37th IEEE Photo- voltaic Specialists Conference (2011). Web. 8 April 2014. http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6186079&sortTy pe%3Dasc_p_Sequence%26filter%3DAND%28p_IS_Number%3A6185829%29%26pageNumber%3D6%26rowsPerPage%3D50. 4 “Accelerated Aging: Challenge, Opportunity and Necessity,” B. Jaeckel, et al, Photovoltaic Module Reliability Workshop 2011. Web. 8 April 2014. http://www.nrel.gov/docs/fy14osti/60170.pdf. 5 “Test-to-Fail of Crystalline Sil
- [2] PV_Connectors_Energy__075705d0 — authority
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of some metals to high humidity and other environmental stressors; – Supply-chain pressures that lead to cost-cuts in manufacturing, including materials substitution and reduction; – Prevalence of low-quality replacement connectors that are vulnerable to ingress of moisture /and particulates. A Four-Part Investigation Our research spans these topic areas: Onsite inspections include visual inspections for evidence of cross-mating, separation or loose connections, and signs of heat deformation; and thermal inspection via a handheld long-wave infrared camera. Onsite data collection will include connector type, manufacturer and serial number, if known, location of connector in the array, and site metadata, including module make and model, system age, climate zone, exposure to extreme weather, etc. This task will also include development of a master spreadsheet to ensure thorough and consistent data across multiple sites. Connectors removed from photovoltaic systems as a result of onsite inspections, commercially off-the-shelf connectors and connectors obtained via the project’s mail-in program, will be subjected to materials characterization and forensics analysis. The COTS connectors will represent a statistically significant number of each type, based on such data as market share, unit price, morphology and country of origin, and will provide important data on the variation in quality of connectors being sold in the US. Techno-economic analysis (TEA) data will be collected in p
- [4] Degradation_and_Failure_Modes_in_New_Photovoltaic_Cell_-_IEA-PVPS__47a6a12d — authority
source passage
in a single process solving all challenges at once. “The new report, Degradation and Failure Modes in New Photovoltaic Cell and Module Technologies, highlights key factors that impact the reliability of advanced solar technologies,” said Marc Köntges, a leading author of the report. “We identified common failure mechanisms and provide insights to improve long-term reliability and efficiency. These findings pave the way for more robust and sustainable solar energy solutions, supporting the transition to cleaner energy worldwide.” This report also provides Photovoltaic Failure Fact Sheets (PVFS) 2025, offering practical and field-oriented information crucial for planners, installers, investors, inspectors, consultants, and insurance companies engaged in the solar energy sector.
- [6] UNSW_Next-gen_solar_module_could_degrade_faster_than_expected__bfa0f162 — authority
source passage
you could expect depending on your location,” corresponding author Dr Poddar said. “It gives a holistic overview for manufacturers or developers who want to install panels somewhere, without having to do all the background calculations themselves.” The findings carry particular significance as the solar industry rapidly deploys advanced high-efficiency technologies designed to capture a broader portion of the solar spectrum, including ultraviolet light. While traditional silicon solar modules primarily rely on visible and infrared light to generate electricity, newer cell architectures such as TOPCon and heterojunction are engineered to harness UV radiation for improved conversion efficiency. That improvement, however, may come with unintended consequences for long-term reliability, with recent research documenting notable UV sensitivity in certain next-generation designs. “Our results highlight that modules with similar technology and orientation can still exhibit region-specific degradation,” the researchers state in the paper. “This is due to the influence of local weather and climate when exposed to outdoor conditions. This underscores the need for climate-specific indoor testing and accelerated tests for reliability and better lifetime predictions. “Notably, UV photodegradation alone can account for nearly a quarter of the total annual degradation in monocrystalline silicon modules in regions with high UV dose, potentially reducing system lifetime by seven to ten years.”
- [8] Durability_is_more_important_than_record-breaking_solar_cell_efficienc__14cd2dc1 — magazine
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will produce significantly less energy over their lifetime, regardless of the high efficiencies achieved in the lab. When introducing new technologies, if they fail to demonstrate reliability, they will struggle to gain trust from investors, regulators and consumers. Stability is a key factor in building credibility for new materials and designs. Solar panels are a long-term investment for both residential and commercial installations. Frequent replacements or repairs due to instability increase the overall cost of ownership, making solar less attractive to consumers and businesses. Instability also impacts large-scale solar farms, where replacing many solar panels becomes a logistical and financial challenge. Panels with short lifespans also contribute to the growing issue of solar waste. As installations scale globally, ensuring durability can help minimize the environmental footprint of solar technology. In this sense, stability aligns with the sustainability ethos of renewable energy by reducing resource consumption over time. Plus, the degradation of some new solar materials can be dangerous. Perovskite solar cells contain lead-halide complexes that dissolve in water. Without proper encapsulation there are risks of these poisoning the local environment. Reframing industry priorities The solar industry’s obsession with efficiency is understandable. Efficiency metrics are easy to communicate, resonate with consumers and drive scientific notability. However, for solar energ
- [9] Durability_is_more_important_than_record-breaking_solar_cell__14cd2dc1 — authority
source passage
will produce significantly less energy over their lifetime, regardless of the high efficiencies achieved in the lab. When introducing new technologies, if they fail to demonstrate reliability, they will struggle to gain trust from investors, regulators and consumers. Stability is a key factor in building credibility for new materials and designs. Solar panels are a long-term investment for both residential and commercial installations. Frequent replacements or repairs due to instability increase the overall cost of ownership, making solar less attractive to consumers and businesses. Instability also impacts large-scale solar farms, where replacing many solar panels becomes a logistical and financial challenge. Panels with short lifespans also contribute to the growing issue of solar waste. As installations scale globally, ensuring durability can help minimize the environmental footprint of solar technology. In this sense, stability aligns with the sustainability ethos of renewable energy by reducing resource consumption over time. Plus, the degradation of some new solar materials can be dangerous. Perovskite solar cells contain lead-halide complexes that dissolve in water. Without proper encapsulation there are risks of these poisoning the local environment. Reframing industry priorities The solar industry’s obsession with efficiency is understandable. Efficiency metrics are easy to communicate, resonate with consumers and drive scientific notability. However, for solar energ
- [11] On-Site_Next-Generation_Solar_Testing_and_Inspection_Faster_and__4d2db2d1 — authority
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# On-Site Next-Generation Solar Testing and Inspection: Faster and Smarter Source: Blog/Web URL: https://www.intertek.com/solar/onsite/ Author: Date: 2025-09-05 Identify microcracks, underperformance, and safety risks without shipping modules. Gain actionable data and on-site optimizations with the industry's most advanced mobile labs and drone technology Intertek’s on-site photovoltaic (PV) testing services provide an essential solution for site owners, operators, EPC (Engineering, Procurement, and Construction) firms, and O&M (Operations and Maintenance) teams looking to maximize the efficiency and reliability of solar installations. Our field-testing experts deliver fast, accurate data to validate solar energy output, ensuring that every PV module meets critical performance standards from commissioning through long-term operation. Enhance Energy Production and ROI Our on-site solar testing services are designed to optimize energy production across all PV installations, helping stakeholders identify performance issues early to reduce downtime and enhance system return on investment (ROI). By capturing detailed performance data, we empower site owners and operators to maintain peak output and minimize risk through proactive maintenance. Comprehensive field assessments also enable streamlined warranty management, making it easier to resolve warranty claims and prepare for asset transitions. Intertek’s PV field testing services provide safety and performance testing, deliverin
- [16] Understanding_and_preventing_PV_module_glass_fracture__0db3e70f — authority
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# Understanding and preventing PV module glass fracture Source: Blog/Web URL: https://www.vde.com/en/vde-americas/newsroom/pv-module-glass-fracture-byline?trk=public_post_comment-text Author: Date: 2025-09-19 Solar glass fracture is a probabilistic event that occurs based on a combination of internal and external factors, many of which are hiding in plain sight. As an example, module manufacturers have largely continued to treat solar glass as a commodity—meaning it is rarely subject to batch traceability or lot tracking—even though tempering process control becomes more important as modules get bigger, as shown in Figure 6. Meanwhile, forensic analysis has revealed evidence that glass supply chain plays at least some role in the proliferation of low-energy glass fracture. “A developer came to RETC recently with two side-by-side projects,” recounts Kedir. “While both sites used modules from the same manufacturer, the number of cracks exhibited on one site was an order of magnitude higher than the other. Testing modules from the site experiencing glass failure, we found that 75% of samples tested under the design load rating. It turned out that the modules at these side-by-side sites came from two different production lines, each supplied by a different glass manufacturer.” If a change in glass vendor at the point of production can account for an order of magnitude difference in early mortality in the field, why isn’t this variable part of a standard bill of materials (BOM) ve
- [17] Do_We_Need_Solar_Inverter_Reliability_Standards__81655bbf — magazine
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marketplace in the long term.” —Brad Dore, Director of marketing, SMA America“Module reliability is an important aspect in the industry, specifically if it can be translated to bankability, lower cost of capital etc. Tigo Energy believes that using information technology and connecting modules into the internet of things (IOT) will enable the industry to translate material quality, module construction and field behavior into the more valuable, predictable long-term performance of the asset. This will lower the industry’s risk level, increase the availability of lower-cost funding and improve market adoption.” — James Bickford, Tigo Energy“Since about 2 out of every 3 installations in the U.S. residential market are now built with module level electronics, it’s overdue to evaluate how we test them. Our philosophy is that components that go near or on the modules should be tested with a similar methodology as modules. That means that module-level electronics need to be tested for thermal cycle, damp heat and humidity freeze. They also need electrical component testing that solar modules don’t require, such as burn-in tests.” —Michael Rogerson, North America marketing manager, SolarEdge“We believe that the entire PV market needs a dedicated focus on reliability, and that includes inverters and power electronics of all kinds. Most string and central inverters have, at best, a 10-year design life, and most of the leases and PPAs out there are less than five years old. The industry
- [20] Damp_heat_UVID_testing_are_highest_percentage_of_red_flag_-_PV_Tech__d915c629 — authority
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ongoing antidumping and countervailing duty (AD/CVD) investigations, these “highly refined manufacturing processes” move outside of China, where there is considerable expertise in these processes. “There are steps in the manufacturing process that dictate a cell’s ability to withstand some of these light-induced degradation modes,” said Kedir. “Manufacturers need to tightly control these steps. But if you take a highly refined manufacturing process out of China and move it to Africa, Eastern Europe, or the US, plant operators need to substantially revise the process definition. “Without adequate batch testing, PV modules from a new factory could have a very different reliability profile, even though companies are nominally using the same manufacturing equipment and an identical BOM [bill of materials].” RETC awards 13 ‘overall highest achiever’ status However, the report is not without positives. Backsheet ultraviolet durability testing returned 100% of tests in the high achievement category, while light- and elevated temperature-induced degradation returned a high achiever percentage of 66%, the two highest figures for testing types that returned no red flags. RETC also awarded a total of 13 companies its “overall highest achiever” status—Imperial Star, JA Solar, JinkoSolar, LONGi, Qcells, Runergy, Solarspace, Thornova, TrinaSolar, TW Solar, VSUN, Waaree and Yingli Solar—up from 12 the previous year. Nine of these companies—JA Solar, Jinko Solar, LONGi Solar, Runergy, Solars
proven scientific test procedures to screen PV modules for reliability, performance and safety. UL’s performance and reliability services for PV modules provide third-party evidence of industry standard testing to assess consistency in the manufacturing process that also includes technical inspections of PV module factory operations. Additional tests can be conducted to demonstrate the impact of long-terms stresses on PV module performance and safety. 1 “Development and application of a UV light source for PV-module testing,” M. Koehl, et al, 24th European Photovoltaic Solar Energy Conference (2009). Web. 8 April 2014. http://www.eupvsec-proceedings.com/roceedings?paper=4697. 2 “Reliability of PV-modules – Natural, accelerated and simulated degradation,” M. Koehl, et al, SPIE Conference 7048-4, September 2008. Web. 8 April 2014. http://www.iea-pvps.org/index.php?id=15&eID=dam_frontend_push&docID=272. 3 “System voltage potential-induced degradation mechanisms in PV Modules and Methods for Test,” P. Hacke, et al, 37th IEEE Photo- voltaic Specialists Conference (2011). Web. 8 April 2014. http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6186079&sortTy pe%3Dasc_p_Sequence%26filter%3DAND%28p_IS_Number%3A6185829%29%26pageNumber%3D6%26rowsPerPage%3D50. 4 “Accelerated Aging: Challenge, Opportunity and Necessity,” B. Jaeckel, et al, Photovoltaic Module Reliability Workshop 2011. Web. 8 April 2014. http://www.nrel.gov/docs/fy14osti/60170.pdf. 5 “Test-to-Fail of Crystalline Sil
of some metals to high humidity and other environmental stressors; – Supply-chain pressures that lead to cost-cuts in manufacturing, including materials substitution and reduction; – Prevalence of low-quality replacement connectors that are vulnerable to ingress of moisture /and particulates. A Four-Part Investigation Our research spans these topic areas: Onsite inspections include visual inspections for evidence of cross-mating, separation or loose connections, and signs of heat deformation; and thermal inspection via a handheld long-wave infrared camera. Onsite data collection will include connector type, manufacturer and serial number, if known, location of connector in the array, and site metadata, including module make and model, system age, climate zone, exposure to extreme weather, etc. This task will also include development of a master spreadsheet to ensure thorough and consistent data across multiple sites. Connectors removed from photovoltaic systems as a result of onsite inspections, commercially off-the-shelf connectors and connectors obtained via the project’s mail-in program, will be subjected to materials characterization and forensics analysis. The COTS connectors will represent a statistically significant number of each type, based on such data as market share, unit price, morphology and country of origin, and will provide important data on the variation in quality of connectors being sold in the US. Techno-economic analysis (TEA) data will be collected in p
in a single process solving all challenges at once. “The new report, Degradation and Failure Modes in New Photovoltaic Cell and Module Technologies, highlights key factors that impact the reliability of advanced solar technologies,” said Marc Köntges, a leading author of the report. “We identified common failure mechanisms and provide insights to improve long-term reliability and efficiency. These findings pave the way for more robust and sustainable solar energy solutions, supporting the transition to cleaner energy worldwide.” This report also provides Photovoltaic Failure Fact Sheets (PVFS) 2025, offering practical and field-oriented information crucial for planners, installers, investors, inspectors, consultants, and insurance companies engaged in the solar energy sector.
you could expect depending on your location,” corresponding author Dr Poddar said. “It gives a holistic overview for manufacturers or developers who want to install panels somewhere, without having to do all the background calculations themselves.” The findings carry particular significance as the solar industry rapidly deploys advanced high-efficiency technologies designed to capture a broader portion of the solar spectrum, including ultraviolet light. While traditional silicon solar modules primarily rely on visible and infrared light to generate electricity, newer cell architectures such as TOPCon and heterojunction are engineered to harness UV radiation for improved conversion efficiency. That improvement, however, may come with unintended consequences for long-term reliability, with recent research documenting notable UV sensitivity in certain next-generation designs. “Our results highlight that modules with similar technology and orientation can still exhibit region-specific degradation,” the researchers state in the paper. “This is due to the influence of local weather and climate when exposed to outdoor conditions. This underscores the need for climate-specific indoor testing and accelerated tests for reliability and better lifetime predictions. “Notably, UV photodegradation alone can account for nearly a quarter of the total annual degradation in monocrystalline silicon modules in regions with high UV dose, potentially reducing system lifetime by seven to ten years.”
will produce significantly less energy over their lifetime, regardless of the high efficiencies achieved in the lab. When introducing new technologies, if they fail to demonstrate reliability, they will struggle to gain trust from investors, regulators and consumers. Stability is a key factor in building credibility for new materials and designs. Solar panels are a long-term investment for both residential and commercial installations. Frequent replacements or repairs due to instability increase the overall cost of ownership, making solar less attractive to consumers and businesses. Instability also impacts large-scale solar farms, where replacing many solar panels becomes a logistical and financial challenge. Panels with short lifespans also contribute to the growing issue of solar waste. As installations scale globally, ensuring durability can help minimize the environmental footprint of solar technology. In this sense, stability aligns with the sustainability ethos of renewable energy by reducing resource consumption over time. Plus, the degradation of some new solar materials can be dangerous. Perovskite solar cells contain lead-halide complexes that dissolve in water. Without proper encapsulation there are risks of these poisoning the local environment. Reframing industry priorities The solar industry’s obsession with efficiency is understandable. Efficiency metrics are easy to communicate, resonate with consumers and drive scientific notability. However, for solar energ
will produce significantly less energy over their lifetime, regardless of the high efficiencies achieved in the lab. When introducing new technologies, if they fail to demonstrate reliability, they will struggle to gain trust from investors, regulators and consumers. Stability is a key factor in building credibility for new materials and designs. Solar panels are a long-term investment for both residential and commercial installations. Frequent replacements or repairs due to instability increase the overall cost of ownership, making solar less attractive to consumers and businesses. Instability also impacts large-scale solar farms, where replacing many solar panels becomes a logistical and financial challenge. Panels with short lifespans also contribute to the growing issue of solar waste. As installations scale globally, ensuring durability can help minimize the environmental footprint of solar technology. In this sense, stability aligns with the sustainability ethos of renewable energy by reducing resource consumption over time. Plus, the degradation of some new solar materials can be dangerous. Perovskite solar cells contain lead-halide complexes that dissolve in water. Without proper encapsulation there are risks of these poisoning the local environment. Reframing industry priorities The solar industry’s obsession with efficiency is understandable. Efficiency metrics are easy to communicate, resonate with consumers and drive scientific notability. However, for solar energ
# On-Site Next-Generation Solar Testing and Inspection: Faster and Smarter Source: Blog/Web URL: https://www.intertek.com/solar/onsite/ Author: Date: 2025-09-05 Identify microcracks, underperformance, and safety risks without shipping modules. Gain actionable data and on-site optimizations with the industry's most advanced mobile labs and drone technology Intertek’s on-site photovoltaic (PV) testing services provide an essential solution for site owners, operators, EPC (Engineering, Procurement, and Construction) firms, and O&M (Operations and Maintenance) teams looking to maximize the efficiency and reliability of solar installations. Our field-testing experts deliver fast, accurate data to validate solar energy output, ensuring that every PV module meets critical performance standards from commissioning through long-term operation. Enhance Energy Production and ROI Our on-site solar testing services are designed to optimize energy production across all PV installations, helping stakeholders identify performance issues early to reduce downtime and enhance system return on investment (ROI). By capturing detailed performance data, we empower site owners and operators to maintain peak output and minimize risk through proactive maintenance. Comprehensive field assessments also enable streamlined warranty management, making it easier to resolve warranty claims and prepare for asset transitions. Intertek’s PV field testing services provide safety and performance testing, deliverin
# Understanding and preventing PV module glass fracture Source: Blog/Web URL: https://www.vde.com/en/vde-americas/newsroom/pv-module-glass-fracture-byline?trk=public_post_comment-text Author: Date: 2025-09-19 Solar glass fracture is a probabilistic event that occurs based on a combination of internal and external factors, many of which are hiding in plain sight. As an example, module manufacturers have largely continued to treat solar glass as a commodity—meaning it is rarely subject to batch traceability or lot tracking—even though tempering process control becomes more important as modules get bigger, as shown in Figure 6. Meanwhile, forensic analysis has revealed evidence that glass supply chain plays at least some role in the proliferation of low-energy glass fracture. “A developer came to RETC recently with two side-by-side projects,” recounts Kedir. “While both sites used modules from the same manufacturer, the number of cracks exhibited on one site was an order of magnitude higher than the other. Testing modules from the site experiencing glass failure, we found that 75% of samples tested under the design load rating. It turned out that the modules at these side-by-side sites came from two different production lines, each supplied by a different glass manufacturer.” If a change in glass vendor at the point of production can account for an order of magnitude difference in early mortality in the field, why isn’t this variable part of a standard bill of materials (BOM) ve
marketplace in the long term.” —Brad Dore, Director of marketing, SMA America“Module reliability is an important aspect in the industry, specifically if it can be translated to bankability, lower cost of capital etc. Tigo Energy believes that using information technology and connecting modules into the internet of things (IOT) will enable the industry to translate material quality, module construction and field behavior into the more valuable, predictable long-term performance of the asset. This will lower the industry’s risk level, increase the availability of lower-cost funding and improve market adoption.” — James Bickford, Tigo Energy“Since about 2 out of every 3 installations in the U.S. residential market are now built with module level electronics, it’s overdue to evaluate how we test them. Our philosophy is that components that go near or on the modules should be tested with a similar methodology as modules. That means that module-level electronics need to be tested for thermal cycle, damp heat and humidity freeze. They also need electrical component testing that solar modules don’t require, such as burn-in tests.” —Michael Rogerson, North America marketing manager, SolarEdge“We believe that the entire PV market needs a dedicated focus on reliability, and that includes inverters and power electronics of all kinds. Most string and central inverters have, at best, a 10-year design life, and most of the leases and PPAs out there are less than five years old. The industry
ongoing antidumping and countervailing duty (AD/CVD) investigations, these “highly refined manufacturing processes” move outside of China, where there is considerable expertise in these processes. “There are steps in the manufacturing process that dictate a cell’s ability to withstand some of these light-induced degradation modes,” said Kedir. “Manufacturers need to tightly control these steps. But if you take a highly refined manufacturing process out of China and move it to Africa, Eastern Europe, or the US, plant operators need to substantially revise the process definition. “Without adequate batch testing, PV modules from a new factory could have a very different reliability profile, even though companies are nominally using the same manufacturing equipment and an identical BOM [bill of materials].” RETC awards 13 ‘overall highest achiever’ status However, the report is not without positives. Backsheet ultraviolet durability testing returned 100% of tests in the high achievement category, while light- and elevated temperature-induced degradation returned a high achiever percentage of 66%, the two highest figures for testing types that returned no red flags. RETC also awarded a total of 13 companies its “overall highest achiever” status—Imperial Star, JA Solar, JinkoSolar, LONGi, Qcells, Runergy, Solarspace, Thornova, TrinaSolar, TW Solar, VSUN, Waaree and Yingli Solar—up from 12 the previous year. Nine of these companies—JA Solar, Jinko Solar, LONGi Solar, Runergy, Solars