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The scope of the project BI-FACE is to develop innovative bifacial modules and systems for flat roofs. The results will include three novel variations for bifacial modules and systems which are tested in three different climate areas: subtropical (Cyprus), temperate (Austria) and maritime temperate (Netherlands). The ultimate design of these systems is challenging due to the large number of parameters that influence the energy yield (e. g. tilt and distance between modules, reflecting surfaces, shading, cell spacing, materials used and weather conditions).

A holistic approach to energy performance needs to take the aspect of standardization into account. This standardization is currently lacking for bifacial modules, hindering rapid market introduction. Therefore, critical effort will be put in to harmonized performance characterization of bifacial PV modules in a factory and laboratory settings and correlate this with the outdoor performance. The results will be supplied to the standardization committees of bifacial modules.

The layout and mounting design of a bifacial system is critical to obtain the maximum possible performance on flat roofs. The construction demands with respect to wind load, stability, total weight (incl. ballast) and maximum allowed weight on a roof are directly influenced by this and need to be critically examined in parallel. The intended approach will compare theoretical investigations with tests in the laboratory and in the field.

The project BI-FACE aims to develop technically as well as economically novel bifacial PV systems to exploit the enormous potential of this technology.


  • Novel lightweight bifacial modules and systems for flat roofs for representative climates in Europe
  • Innovative, comprehensive models for design and installation of bifacial modules and systems including construction requirements
  • Novel manufacturing strategies
  • New performance and characterization measurements
  • Innovative mounting structures

The main expected results of the project

1.    New validated simulation tools for bifacial modules and systems, including simulation of the wind load

2.    Modeled and validated standardization advice for characterization of bifacial modules

3.    New high efficiency bifacial modules and systems

4.    Outdoor performance qualification of the bifacial system in different European climate zones and wind and snow load conditions

5.    Guidelines for flash tester upgrade at the module manufacturer’s site


Another innovation concerns performance evaluation after module manufacturing. During the project, strategies to accurately obtain the module performance with the flash tester, available at the manufacturer’s site, will be evaluated and integrated into the standardization process, which is in development at the moment. The consortia leader AIT is already member in these committees and therefore has the possibility to transfer knowledge of this international community to the project and in return to disseminate and influence the standardization processes with the results of the project.

With the consortium and with the projects targets, the full European market is represented to create a holistic approach to the performance of the bifacial modules and system. Tempress as equipment manufacturer for bifacial cells they will supply the consortium with the bifacial cells using European technology. The cells integrated in the bifacial modules will be done by PVP and Tempress.

Validation and platform formation for standardization on how to correctly characterize bifacial modules in lab and fab will be done by AIT and CTR. The results will be provided to the international standardization committee. This will create the regulation platform needed to further market penetration of bifacial technology. The modules and systems are researched in combined modeling effort of ECN, CTR and AIT as development of modules and systems cannot be done separately. The modules and systems are validated by ECN, CTR and AIT, which is used as input for the modeling. Outdoor tests are done throughout Europe to represent all climate zones and a final system prototype is placed at Tempress, on a flat roof of their factory besides their existing commercial bifacial system.