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Photovoltaic module life time forecast and evaluation

Periodic Reporting for period 2 - SOLAR-TRAIN (Photovoltaic module life time forecast and evaluation)

Reporting period: 2018-09-01 to 2020-08-31

The quality assurance in the photovoltaic industry is yet in its infancy, requiring both underpinning science and trained personnel to reduce costs of energy. An unmet industrial requirement is an accelerated and operating environment specific service life time and energy yield assessment. SOLAR-TRAIN has qualified selected early stage researchers in the field of PV durability as part of a highly innovative, multi-disciplinary project meeting industry requirements. The objective was to develop novel, validated models for the service life time and energy prediction of PV modules and systems. The elements to this puzzle were researched in the frame of 14 MSCA Fellowships with individual areas of focus, such as
• climatic degradation factors,
• system analytics,
• material (polymer) parameters,
• service life & energy models,
• linking production to performance and
• performance enhancement by improved O&M.
The project was integrated both in terms of research as well as training. This inter-sectoral approach provided excellent theoretical and technical background as well as immersion in different business sectors and career mentoring, allowing ESRs to build up a sustainable professional network across Europe. To enable a most effective cross-sectoral training, the project’s beneficiaries and partners represent the entire value chain, from materials developers / manufacturers through to operators and insurance companies. SOLAR-TRAIN has delivered on the targets stated in Issue Paper No. 2 of the SET Plan to maintain and strengthen PV technology leadership in Europe.
The project Solar-Train started with an extensive recruitments process. The recruited ESRs received an extensive training in their host institutions and also in the Beginners’ Week and the three Summer Schools in 2017, 2018 and 2019 to ensure that they have the necessary know-how on PV technology.
The scientific work already yielded valuable results which triggered a lot of interest in the international PV community. Related to the climatic impacts on PV systems, the most crucial climatic impacts for degradation effects have been identified. Existing climate classifications have been analysed and a classification adapted to the needs of PV technology have been proposed. The identified crucial impacts were also used in laboratory tests and two new setups for material tests have been designed and applied as prototypes.
The identified most relevant degradation patterns were also used as focus topics for the development of tests and the investigation of materials for PV-modules. Several sets of samples to investigate specific degradation effects have been developed and produced and were exposed to newly developed multi-stress accelerated ageing tests. This work was also used to develop alternative methods to identify degradation effects at an early stage..
The work on reproduction of degradation effects was accompanied by material research with special focus on polymeric components of PV-modules. Especially in terms of understanding material interactions significant results have been already achieved.
All the results and data mentioned above were also used to develop models which enable the prediction of the degradation and yield of PV modules and systems consisting of different components and installed in different climates. Basic mathematical modelling approaches have been studied for their applicability for PV modules. An approach has been selected which offers the possibility to include different climatic conditions with different combinations of load-parameters and also different module types, represented by different expectable degradation processes. In parallel, the effect of different degradation modes of PV modules on the yield of complete power plants has been analysed. Methods were developed to identify specific module degradation modes and to optimize O&M using systems data.
1. Climatic degradation factors
This work aimed to understand which failure modes occur in different environments. A practical outcome has been a screening approach for failure modes that can be carried out in highly accelerated conditions. The work further aims at the development of data sets that allow the classification of geographical regions according to their climatic loads. Therefore it was focusing on the calculation of synergistic effects of different climatic factors (T, r.h. UV, TC...) with regard to degradation effects in materials and full modules.
2. Analysing degradation and failure modes of PV modules
The aim was to achieve a comprehensive understanding of the degradation mechanisms in the field and the possibility of tracing them back to the manufacturing steps. That process has been done through the identification of failure modes as well as the investigation of critical parameters in the manufacturing line that can provide an early signal of potential degradation. Early degradation or failures, as well as standard aging mechanisms, were analysed. The goal was to define figures of merit applicable to the manufacturing process to stop/modify/rework product fabrication.
3. Evaluation of polymeric materials in PV modules
This WP dealt with the investigation and evaluation of polymeric materials which are utilized in and promising new materials for PV modules. Prominent PV module degradation and failure modes like yellowing, delamination, potential induced degradation or corrosion are directly linked to the degradation behaviour of the polymers. The focus of the research was on the weathering stability of the materials as well as on the interactions of the different materials within a PV module for different stress factors and micro-climates.
4. Service life time prediction of PV modules and systems and related economic impact
The aim of this WP was to develop degradation models that allow a prediction of the service lifetime of PV modules and systems, including internal and external aspects, such as e.g. material properties, materials interactions, and climatic influences. The main focus was on the identification of the relevant processes like hot spots, cracks, PID, UV embrittlement, delamination, influencing (climatic) factors and the related kinetics for the degradation for PV modules. This way, a path-breaking tool for the climate- and module-dependent calculation of the yield of a PV plant throughout its lifetime shall be provided.
There has been also a substantial impact besides the personal development of the ESRs on the quality and excellence of PV reliability research in Europe. The project addresses some of the most crucial scientific topics of PV like material interaction and location specific service-life and yield prediction for PV- modules and systems. As first results already could be presented to the scientific community and industry at the beginning, it was foreseeable that there will be a significant improvement of the know-how on PV reliability in Europe by the project. Solar-Train was one of the biggest or the biggest coordinated activity on PV reliability in Europe and its approach and results are very well recognized up until today. Project representatives have been invited to scientific events and also been asked for cooperation several times from international industrial and scientific organisations and journals which can be seen as catchable proofs for that statement.