TÜV Rheinland Quality Monitor Solar 2013: Cost Pressure Increases Risks to Quality of Solar Systems

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1 TÜV Rheinland Quality Monitor Solar 2013: Cost Pressure Increases Risks to Quality of Solar Systems Extensive study on quality and safety of photovoltaic modules and solar systems presented at Intersolar Europe / Trends of past ten years analyzed / Installation quality of systems: One third of all systems defective / Search for cost reductions negatively impacts quality / Solar modules: Workmanship quality varies greatly Cologne/Munich, June 19, TÜV Rheinland, the independent testing service provider, used Intersolar Europe as an opportunity to present the Solar 2013 quality monitor. For the first time, experts from the solar industry's leading testing company analyzed comprehensive data material from the past few years so that they could evaluate the current state of the art with regard to quality and industry trends. The study showed that: "There is a pressing need to improve quality throughout projects to plan and implement photovoltaic systems," states Willi Vaaßen, Head of the Solar Energy division at TÜV Rheinland. In previous years, around 30% of all large-scale systems approved by TÜV Rheinland have shown serious defects relating either to severe safety-relevant faults that require direct action or to a substantial number of faults that significantly impair system functionality. In addition, according to Vaaßen: "Half of all faults identified are installation errors." Analyses by TÜV Rheinland indicate that laboratory tests on photovoltaic modules must establish whether new module types have been well engineered to meet the requirements of the requisite IEC design certification. The number of faults detected in certification tests has decreased significantly: In 2002, 54% of all modules were still failing the IEC design certification at TÜV Rheinland in Germany. By 2012, the error rate had fallen rapidly to 10%. Although a very good sign, only limited conclusions can be drawn about the quality of modules in series production. Jörg Althaus, also Head of Solar Energy at TÜV Rheinland, comments: "Our more extensive tests on the workmanship quality and longevity of modules show that some manufacturers are not capable of ensuring consistently high quality in series production." In addition, experts believe that while the quest to

2 - 2 - save money in modules may well lead to innovations, the targeted material savings can have a negative impact on quality. Althaus: "At present, manufacturers are often overhasty in launching new products on the market, even if they are still having teething problems." A deterioration in the quality of testing and certification can also be seen around the world, as well as a reduced propensity among manufacturers to consistently abide by certification rules. For this reason, TÜV Rheinland is calling for a solar quality road map to ensure acceptance in society of solar energy and safeguard its reliable contribution to the energy transition in the long run. According to the experts at TÜV Rheinland, a program of this type would center on improving quality assurance processes in production and installation. This must incorporate intensified monitoring of these measures during production and in the end product including the use of market observation instruments as well as random testing of photovoltaic modules in specific projects and monitoring of the quality of the installation and system construction and operation. For the Solar 2013 quality monitor, the experts at TÜV Rheinland used its solar laboratory in Cologne to analyze the fault statistics in photovoltaic modules tested between 2002 and 2012 as well as errors in the initial acceptance of large-scale systems performed by the experts in previous years. The Solar quality monitor also incorporates the results of the PV+Test and energy yield test carried out by TÜV Rheinland for various photovoltaic modules, allowing the reliability of electricity generation and the energy yield to be compared. Finally, the study also uses the initial results of a research project examining fire protection in photovoltaic systems. Product Testing in the Laboratory: Fault Analysis for Photovoltaic Modules in Detail TÜV Rheinland has analyzed a total of 2,000 certification projects conducted at the Cologne Solar Testing Center over the past ten years. A certification project can cover several variants of the same module type because manufacturers often exchange and attain qualifications for a variety of materials. These are based on

3 - 3 - the design certifications in accordance with IEC and and the safety qualification in accordance with IEC A long-term trend can be clearly identified here: While 54% of all modules were still failing the IEC design certifications in 2002, by 2007 this had risen to 67% for the new thin-film modules and 29% for the new crystalline photovoltaic modules. At the time, this high fault rate was attributed to the large number of new module manufacturers on the market originating from Asia in particular. By 2012, the fault rate for both technologies had dropped to 10%. The experts ascribe this not only to the fact that manufacturers have learned to fulfill the IEC standards when constructing new module types but also to the ongoing development of the market. The distribution of faults indicates parallels between crystalline modules (1,740 certifications) and thin-film modules (370 projects analyzed): Of those projects in which tests were failed, 49% of all crystalline modules and 43% of all thin-film modules in the TÜV Rheinland test center failed during the four prescribed test series in the climate chamber, which include temperature changes between -40 C and +85 C. The climate chamber tests are a good ind ication of the longevity to be expected, the quality of the materials and the workmanship of the products. However, it is also notable that 11% (crystalline) and 12% (thin-film) of faults occurred during the required incoming inspection and measurement, that is, before any load tests had actually been carried out. These modules failed, for example, because the information on the model plate did not meet requirements or because they already exhibited damage. Modules: Fault Analysis in Detail For 2006 to 2012, the experts at TÜV Rheinland analyzed the development of key test fault categories in crystalline modules in the laboratory: Cycle tests in the climate chamber (-40 C to +85 C), 1,000-hour moistu re/thermal tests at 85 C and 85% humidity and the mechanical load test (tensile and pressure) at 2,400 pascals. The moisture/thermal test proved critical throughout. Here, the proportion of faults is always between 29% (2006) and 21% (2011); in 2012, it was 24%.

4 - 4 - The lamination is most affected by the test. Up to 2008, the number of faults during the temperature cycle tests rose to 39% and then dropped to 16% by Jörg Althaus: "The market development is plain to see here as manufacturers moved from manual to automatic soldering and rapidly reduced the thickness of solar cells." Althaus links the leap to 24% in 2012 to the huge drive to optimize the soldering procedures and soldering pastes used for solar cells. "Introducing many new features in a short space of time also makes faults more likely." Module performance in the mechanical load test has gradually worsened from a fault rate of 2% in 2006 to 16% in According to the experts at TÜV Rheinland, this shows very clearly that to reduce costs, manufacturers have sought new ways to save on materials that have not always proved successful for example with regard to module frames. And the fault rate has increased accordingly. Quality Defects in Modules: Laminate Properties and Cross-Linking Additional tests by TÜV Rheinland show that the data in the design certifications gives only limited indications as to the quality of the modules on the market. To examine the workmanship quality of modules in more detail, TÜV Rheinland tests a product's level of cross-linking and lamination. There are currently no standardized procedures for this area. Modules are taken from the market for both tests. TÜV Rheinland performs these supplementary tests which are quicker than the protracted tests conducted in the climate chamber on behalf of project engineers and investors to see whether modules meet the required quality. The tests enable direct conclusions to be drawn about the workmanship quality of modules. When modules are produced, films made of ethylene-vinyl acetate (EVA) are joined together and used to embed the cells. In 2012/2013, TÜV Rheinland used chemical analyses to determine the level of material cross-linking in a total of 310 samples from 36 different module types (23 manufacturers). Experience has shown the experts that cross-linking is usually between 68% and 90%. In 30 samples, crosslinking was sometimes significantly below this level. Jörg Althaus: "It is highly unlikely that these modules will last for 20

5 - 5 - years and yield returns." 50 samples demonstrated cross-linking of more than 90%. The experts regard this as critical too, because too high a value can make the materials too stiff. If the module is used outdoors for a prolonged period, this also entails a risk of operational failure. In a further series of tests performed on 25 modules in 2012, TÜV Rheinland used "rip-off tests" special tensile tests that target the reverse side films to examine laminate quality. Considerable differences emerged even between unloaded modules in mint condition: Destructive tests showed the adhesion of the reverse side films to be between just 30 N/cm and the highest value of 230 N/cm. After the rip-off test, TÜV Rheinland also subjected four different module types to a 1,000- hour moisture/thermal test in the climate chamber and then performed another tensile test on the reverse side films. This aimed to establish the extent to which film adhesion diminishes during the lifetime of the modules. And here too, the quality of workmanship and materials differed significantly. Adhesion of the reverse side films decreased by around 30% to 40%, although acceptable values were still achieved. TÜV Rheinland is working to expand this procedure for testing workmanship quality to offer project engineers and investors reliable supplementary tests that quickly indicate the quality of modules used. These tests are also part of TÜV Rheinland's new quality benchmark that is to prove whether the modules supplied for a system actually fulfill the properties agreed. TÜV Rheinland does this by taking the modules as test samples straight from the delivery batch. The tests are carried out at TÜV Rheinland's solar laboratory in Cologne. Safety tests, tests of the workmanship and production quality (such as determining the level of cross-linking and the rip-off test), performance tests and tests relating to potential-induced degradation (PID) are carried out. TÜV Rheinland's quick performance check also allows modules to be tested directly in the project. This check is designed to deliver information that is representative for a project or manufacturer about the power output of the modules and about any damage or quality defects caused by micro-cracks in modules. The experts

6 - 6 - calculate the required sample size for modules checked by TÜV Rheinland in a statistically accurate fashion with software on the basis of the flasher measurements of the module manufacturer. The aim is to reduce costs and increase efficiency. The modules are taken directly from the project here too. PV+Test: On the Lookout for "Good" Solar Modules The PV+Test aims to analyze and compare the quality and longevity of photovoltaic modules and, in doing so, look for "good" solar modules. According to the experts at TÜV Rheinland, the results of the PV+Test received so far for photovoltaic modules, which TÜV Rheinland has been carrying out for two years now together with Solarpraxis AG of Berlin, show that manufacturers incorrectly estimate the actual quality of their own photovoltaic modules in part. PV+Test is a comparative test in which modules are awarded grades. The assessments performed in the PV+Test go far beyond the prescribed IEC requirements. The main criteria are safety (25%), resistance to aging (25%), power output (20%), documentation and installation instructions (15%), workmanship (10%), and warranty terms (5%). A total of 21 module types have been analyzed to date, although in nine cases manufacturers chose not to publish the results. This is possible because PV+Test provides a positive list of the good modules on the market. However, it shows that the manufacturers themselves were not satisfied with the results, even though the testers graded four of these modules as "Good" and one even as "Very good (-)." "At the same time, our comprehensive and practical tests emphasize that there certainly are good photovoltaic modules on the market that yield long-term returns," summarizes Vaaßen. Up to now, five modules tested were judged to be "Very good." with another 12 graded as "Good." Three modules were found to be "Satisfactory" and one was deemed "Adequate." TÜV Rheinland and Solarpraxis buy the modules for the tests anonymously in retail outlets. Ongoing recording of power output measurements is of particular importance in the tests and takes place both before the tests and after the relevant test phases. This indicates which modules have weaknesses and where.

7 - 7 - Energy Yield Test: Identifying the Actual Yield For operators and investors, one of the most important quality aspects of photovoltaic modules is their actual energy yield. To determine this, TÜV Rheinland has developed the energy yield test: Here, experts perform an outdoor test in a moderate climate over one year to identify the energy yield of photovoltaic modules, which is then compared with the manufacturer's information and the power output measurements taken under standard test conditions in the laboratory. The last energy yield test completed, which lasted until September 2012, indicated large differences: In practice, the energy yield of the 14 modules measured was up to 5% greater or lower. To ensure sound results, measuring stands must offer maximum precision. TÜV Rheinland has used its many years of experience to implement the measuring technology and measurement principles. As with the PV+Test, the energy yield test also shows that tests conducted under real-world conditions are more likely to provide reliable quality statements than prototype tests in the laboratory. "The one-time design certification is indispensable for fundamental quality and safety. But that's not all: Manufacturers need to constantly invest in quality. And anyone looking for high-quality modules on the market should not fail to take into account further independent test results," states Althaus. The market now offers suitable opportunities for this, as shown by the results from TÜV Rheinland. Checking Solar Systems: Installation Defects Under the Microscope Analyzing the quality of photovoltaic systems is the second largest component of TÜV Rheinland's Solar 2013 quality monitor. Again, these results from the fault analysis of photovoltaic systems show that there is still considerable potential for improvement. Choosing a location, planning and tendering, selecting suitable modules, assembly systems and components, and constructing the system itself from transporting the modules to professional installation and acceptance to operational maintenance and monitoring: Individual project steps that, as TÜV Rheinland's results show, entail significant potential for error. In the current study, TÜV Rheinland analyzed the faults that occurred in 125 large-scale solar systems for which

8 - 8 - its experts have performed the initial acceptance over the past few years. The analysis incorporates ground-mounted systems of up to 25 MWp as well as on-roof systems with output of up to 2 MWp. "Every other fault that we detect is due to incorrect installation. Poor or even dangerous cable routing, incorrect foundation or installation of the support frame, faults in the connections or grounding and so on. One in five systems exhibits (mainly safety-relevant) faults that are so severe that immediate action is required. And a further 10% of systems have a large number of defects," says Willi Vaaßen, summarizing the results. A look at the distribution of faults between individual components and different project steps shows that every point contains serious potential for error. This also confirms statistics from the past few years, for example from insurance companies. 25% of all defects found by the experts occur in the module. In many cases, this is due to incorrect handling or installation. This can mean that modules are damaged before they even become operational. As with cabling faults (14% of all detects detected), this does not necessarily mean that bad products are being used. "But it does show the importance of system acceptance. What's the point of investing in good components, support frames, inverters and modules if they are going to be damaged when the system is constructed or installed in completely the wrong way?" asks Vaaßen. The fact that 18% of all system faults can be attributed to incorrect planning also shows how easy it is to avoid errors from the outset. According to the experts, system acceptance makes sense for larger projects that involve significant investment and in which various sections are implemented by different service providers. Generally, this outlay is not worthwhile for small on-roof systems. Here, it is paramount that the specialist company can prove its quality, be it through appropriate references or through certifications.

9 - 9 - Fire Risks Due to Quality Defects Faults in photovoltaic systems do not just lead to downtime, decreasing yield and possible legal disputes. In extreme cases, they can also increase the risk of fire, particularly when it comes to on-roof solar systems or building-integrated systems. Until 2014, TÜV Rheinland will be working with Fraunhofer ISE and other partners to investigate the connection in a research project on preventive fire protection in photovoltaic systems. Some parts of the project are being sponsored by the German Federal Ministry for the Environment. In this research project, Fraunhofer ISE and TÜV Rheinland examine cases of damage in photovoltaic systems installed on houses and the ground throughout Germany so that they can analyze the causes, circumstances, and effects of defective products or incorrect installations. So far, the project has seen the detailed examination of 180 incidents of heat and fire damage reported around Germany in which the photovoltaic system was cited as a possible cause. According to information from the researchers, this has so far been established in 65 cases a small number considering that more than 1.4 million photovoltaic systems have been installed in Germany. However, Willi Vaaßen observes that: "We know that the fire risk will continue to increase because the number of system continues to rise and these systems will age." The results received so far are based on research within the project itself and a nationwide survey sent to fire personnel and insurers, for example. These figures are not intended to be exhaustive; rather they provide a detailed evaluation of technical risks. There are already indications that, again, at least 50% of all faults leading to heat and fire damage can be attributed to poor installation. It is also worth noting that by far the most fires occur within one or two years of a system being commissioned. Problems with plug connections, connections and cable routing are worth mentioning here in particular. Accordingly, the project will continue to examine the subject of installation quality and recommended courses of action will be derived. Furthermore, 21% of fire incidents were caused by inverters and 20% by the modules themselves.

10 The project also aims to improve understanding of and remedy potential technical fault sources in individual components of solar systems and to improve technical fire protection. TÜV Rheinland Calls for "Solar Quality Road Map" Overall, TÜV Rheinland's Solar 2013 quality monitor indicates significant potential for improvement if solar energy is to be accepted by society and continue to contribute reliably and safely to energy provision in the years to come. However, TÜV Rheinland's investigations also show that suitable instruments and technical solutions already exist that improve and assure quality on a permanent basis. "We can and must learn from the errors of previous years. If greater quality and safety is to be achieved, action is required not only from manufacturers but from everyone involved in the market," concludes Willi Vaaßen. According to the experts at TÜV Rheinland, the core points of a Solar quality road map should address the improved checking and examination of photovoltaic modules in both production and the project as well as monitoring during system construction and operation. Independent testing of production, workmanship quality, energy yield and the longevity of photovoltaic modules has already been developed and is well established at some manufacturers. At the same time, the market must place greater value on these aspects rather than emphasizing cost factors alone. "You can already sense the change taking place here," says Althaus. "Short-term cost savings often prove very expensive in the long run." Benchmark tests such as the PV+Test are a very good indication of which modules offer high quality. And this is why these tests must be expanded further. For large-scale projects with various participants and service providers, TÜV Rheinland also stipulates that new systems should be accepted by professional, ideally independent bodies and maintained on a regular basis thereafter. In the Solar 2013 quality monitor, system installation proved to be a key weak point. Professional acceptance and comprehensive certification of solar systems as offered by TÜV Rheinland in large-scale projects ensure that potential faults are minimized. Providers such as Conergy have already resolved to implement this approach

11 systematically. Methodical system monitoring also helps ensure that faults are identified quickly. Parallel to this, TÜV Rheinland is aiming to further improve the work of specialist installation companies together with market partners and to help investors select qualified companies. This is one way to boost installation quality for a variety of smaller systems in Germany in particular. For this purpose, TÜV Rheinland has developed a comprehensive criteria catalog and, since 2013, has offered a certification service for specialist companies (following a detailed audit) that also involves examining the quality of installations in the field. TÜV Rheinland is pushing ahead with this program together with Mannheimer Versicherung. TÜV Rheinland will continue with the Solar quality monitor in the future and is planning to take the next step and publish the database internationally. Your contact for editorial inquiries: TÜV Rheinland, Jörg Meyer zu Altenschildesche, Press Officer, tel.: / presse@de.tuv.com Internet: