2021-07-15 project

ANOMALOUS – Requirements for testing, documentation and evaluation of anomalies in photovoltaic module backsheets

In the ANOMALOUS project investigations are carried out in order to close the existing normative gap in the evaluation of backsheets of photovoltaic modules in the field and to define uniform criteria for the evaluation of irregularities.

Dominika Radacki
Anna Reuter
Responsible German body
Logo Bundesministerium für Wirtschaft und Klimaschutz

Project term: June 1, 2021 – May 31, 2023

Consortium partners:

  • Fraunhofer-Center für Silizium-Photovoltaik (CSP)
  • Forschungszentrum Jülich GmbH, IEK-11, HI ERN (HIERN)
  • Hochschule Anhalt (HSA)
  • Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW)
  • Aluminium Féron GmbH & Co. KG (Feron)
  • HaWe Engineering GmbH (HaWe)
  • Sunset Energietechnik GmbH (Sunset)
  • Deutsche Kommission Elektrotechnik Elektronik Informationstechnik in DIN und VDE (DKE)

Project funding: The ANOMALOUS project is funded by the German Federal Ministry for Economic Affairs and Climate Action (BMWK) Mas part of the "WIPANO" program (Knowledge and Technology Transfer through Patents and Standards).

Project lead: Projektträger Jülich (PtJ)

Project motivation

In recent years, reocurring inspections of photovoltaic (PV) systems have shown a significant increase in module failures triggered by the polymeric backsheets. Irregularities in polymeric backsheets, such as chalking, delamination, cracking or browning, usually results in degradation of the electrical isolation and increases the risk of electrical shock.

Existing standards and regulations for safety testing primarily focus on the function of new products. Research is conducted in order to understand the underlying degradation mechanisms with the scope to avoid severe reoccurring long-term defects in the future.

However, this work does not address the current need to assess the daily found backsheet issues in the field.

As of today, approximately 60 GWp PV systems are currently connected to the grid in Germany; a large proportion of them are now more than five years old and increasingly exhibit anomalies of the backsheet such as chalking, decoloration and cracking. Several of the observed anomalies are merely cosmetic at this stage, while others pose an inherent electrical safety risk as electrical live parts at high DC potentials are exposed. In addition to electrical safety, a defective backsheet can also result in significant yield loss due to the shutdown of system components.

However, there are no existing recommendations for action in the form of standardized rules and criteria with regard to faulty backsheets. The ANOMALOUS project addresses precisely this shortcoming.

Project description

The investigations carried out within the scope of the ANOMALOUS project serve to close the existing normative gap in the evaluation of backsheets in the field and establish uniform criteria for the evaluation of abnormalities.

Project aims

The project work focuses on the development of a VDE application rule and a standardization application that define criteria for evaluating older PV systems while providing recommendations for action for assessors and maintenance companies. The resulting catalog of abnormalities will also provide more legal certainty in the individual steps of the value chain. In addition, research findings will be made available to the PV market in order to significantly increase the lifetime of PV modules and thus contribute to reducing the carbon footprint required for the production of new modules.

Icon 'please note'

We invite experts, assessors, owners, and operators of PV systems to send their findings to support the ANOMALOUS consortium with the provision of detailed data such as photos showing the PV system and the observed anomaly, on the location of the system, age of the plant, module manufacturer, type of installation, etc. by mail to to develop a comprehensive catalog of anomalies and a reliable guideline. If you have any questions about relevant materials and their use in our project, please feel free to contact us by mail.

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