On April 29, 2026, we successfully hosted our 2nd QUASAR Horizon project webcast, bringing together experts from industry and academia to explore a frequently underestimated topic in photovoltaic (PV) circularity: the role of polymers in PV modules.
While most EOL discussions focus on glass, silicon, and metals, polymer components such as backsheets and encapsulants play a decisive role in module lifetime, recyclability, and overall sustainability. Under the title “The Forgotten Material in PV EoL: Repairing, Recycling & Reducing Polymers in PV Modules”, the webcast explored innovative approaches to repair, recover, and ultimately reduce polymer use in PV modules.
With around 40 registered participants, the strong attendance and active discussions clearly demonstrated the growing interest in polymers as a missing link in future PV circularity strategies.
Polymers: A small share with a large impact
Polymers account for only around 5–15 wt% of a PV module, yet they strongly determine durability, reliability, and recycling quality. In particular:
- Backsheets ensure electrical insulation and protect modules from weathering, moisture, and UV exposure.
- Encapsulants mechanically stabilize the module and shield solar cells and interconnections.
- At end of life, polymer layers are often difficult to separate due to thin, multi‑layered and highly durable designs that were never intended for recycling.
As long as these materials remain unaddressed, high‑value PV recycling will remain limited.
Extending Module Lifetime through Backsheet Repair
Backsheet degradation was identified as a major driver of premature module failure and safety risks. In many cases, such degradation results from inappropriate material selection during module design and insufficient long‑term testing.
Typical degradation pathways start with chalking, followed by micro‑cracks and eventually visible cracking. Over time, this can lead to loss of electrical insulation, moisture ingress and subsequent degradation of encapsulants, solar cells and electrical interconnections — resulting in reduced energy yield, operational disruption and safety hazards.
Guy Beaucarne (Dow Performance Silicones) presented a repair‑oriented solution based on coating degraded backsheets with a flexible, silicone‑based material. The one‑part, moisture‑curing sealant forms an elastomeric layer that restores electrical insulation and protects against water ingress while remaining easy to apply in the field.
A key message was that backsheet degradation follows a chain of events. Interrupting this chain at an early stage allows for thinner coatings, lower material consumption and reduced maintenance costs, making preventive repair a promising strategy for extending module lifetime.
From Obstacle to Resource: Recycling of Backsheets
Backsheets make up only a small fraction of a PV module, but they have a large impact on recycling quality. They are thin, multi‑layer polymer structures designed for long service life – not for easy separation at end of life.
The diversity of backsheet designs is a key challenge for recycling. There is no single “typical” backsheet; instead, many PET‑based constructions with different coatings, pigments and layer combinations coexist in the installed PV fleet.
Katrin Nord‑Varhaug (Norner AS) presented one chemical recycling route for PET‑based backsheets, where PET is chemically depolymerised and recovered as terephthalic acid (TPA) – the main building block for new PET. The approach was demonstrated on real PV backsheet waste with different designs.
A key conclusion was that recycling only enables circularity if material quality is high enough for reuse. To close polymer loops in PV, recycling technologies and material design must be developed together.
Encapsulants as Feedstock for Chemical Recycling
Encapsulants represent another largely untapped polymer stream in PV end‑of‑life management. Caroline Grand (Dow) presented an evaluation of encapsulant films recovered from modules with varying designs, materials and operational histories.
The analysis showed that ethylene‑rich encapsulants are particularly well suited for pyrolysis, yielding higher amounts of carbon‑rich fractions. Under controlled conditions, these materials can support closed‑loop recycling concepts, rather than being down‑cycled or incinerated.
Remaining challenges were also addressed, including the potential need for sorting and cleaning prior to pyrolysis to limit contamination. Within QUASAR, the next steps will focus on lab‑scale pyrolysis of encapsulants, aiming to characterize pyrolysis oils and assess their suitability as cracker feedstock.
Rethinking Module Design to Reduce Polymers
Beyond repair and recycling, the webcast explored how polymer use can be reduced at the design stage.
Christoph Pönisch (Offenburg University of Applied Sciences) introduced the LIFE‑Moduleconcept, which combines back‑contact solar cells with alternative coupling materials. This approach reduces — or potentially eliminates — the need for conventional encapsulant layers by up to 95%, while maintaining optical performance — offering a fundamentally different module architecture.
Such concepts demonstrate that design‑for‑circularity is not limited to improving recyclability, but can also mean avoiding problematic materials altogether.
Outlook
The second QUASAR webcast demonstrated that polymers are no longer a side topic—they are central to the future of sustainable PV. Repair, recycling, and reduction strategies must be developed in parallel to unlock the full circular potential of solar technologies.
QUASAR will continue to advance these approaches through targeted research, lab validation, and collaboration across the PV value chain.
For more details and to access the presentation:
Link to Webcast 2nd QUASAR webcast
