With Resilex aiming to develop resilient value chains for the production of a new generation of PV modules, the project operates on the philosophical foundation of the “3R approach”: Reuse, Recycle, and Reduce. This eco-design methodology moves beyond traditional manufacturing by integrating environmental and circular considerations throughout the product lifecycle. While RESILEX spans the entire value chain, its most transformative technical breakthroughs occur at the cell level, where high-efficiency architectures are being re-engineered to eliminate material vulnerabilities. Here’s the work championed by partners CEA and CSEM.
Breaking the Dependence: Targeting Critical Raw Materials in Solar Cells
The solar cell is the functional heart of any PV system. Modern high-efficiency technologies, specifically Heterojunction (HJT), offer superior performance but currently rely on “hotspots” of high environmental and economic risk: Silver (Ag) for metallization and Indium (In) for Transparent Conductive Oxide (ITO) layers.
RESILEX addresses these vulnerabilities through aggressive eco-design. A primary breakthrough is the “In-less” cell, which has achieved a Technology Readiness Level (TRL) of 7. By utilizing nanocrystalline silicon selective layers, the project has demonstrated the ability to reduce indium content by over 70% with an efficiency loss of less than 0.1% absolute.
RESILEX Eco-Design Strategies for Solar Cells
| Traditional Material/Process | RESILEX Innovation | Strategic Impact |
| Silver (Metallization) | Copper-based screen-printing or Cu-electroplating. | Reduces Ag from 24.6 mg/Wp to 6.8–10.9 mg/Wp. |
| Standard Indium (ITO) | Ultra-thin ITO (15nm) or “In-free” AZO (Aluminum-doped Zinc Oxide). | Eliminates/reduces reliance on volatile CRM markets. |
| Standard PVD Process | AP-SALD (Atmospheric Pressure Spatial Atomic Layer Deposition). | Lowers energy use; eliminates vacuum requirements. |
| Thick Silicon Wafers | Transition to ultra-thin silicon wafers (65 µm). | Lowers polysilicon consumption significantly. |
The “So What?” Factor: Economic and Supply Security
The strategic value of these innovations is quantified through the Cost of Ownership (CoO). In a first hypothetical scenario studied by project partners (S1), the partial substitution of Silver with Copper results in a 42% reduction in metallization costs. When combined with reduced ITO thickness, this translates to a 10% total reduction in cell manufacturing costs. This transition shields European manufacturers from price volatility and scarcity, transforming eco-design from a compliance requirement into a competitive advantage.
Beyond the Cell: Building the Circular Module
If the cell is the heart, the module is the protective housing. Its design dictates long-term reliability and the feasibility of end-of-life (EoL) material recovery. Traditional modules often utilize crosslinking agents and hazardous substances that turn spent panels into “unrecoverable waste.” RESILEX Work Package 4 (WP4) re-imagines the module as a circular asset through several key innovations:
- Bio-based Frames: Transitioning from energy-intensive aluminum to wooden frames to drastically lower the embodied carbon footprint.
- Sustainable Backsheets: Shifting to fluorine-free and bio-based materials (PET, PP, or flax composites) to eliminate toxic off-gassing during recycling.
- Recyclable Encapsulants: Utilizing non-crosslinking Thermoplastic Polyolefin (TPO) instead of standard EVA. This allows for “delamination without destruction,” which is essential for high-purity silicon recovery.
- Lead-Free Interconnections: Employing Zero Busbar (0BB) or Electrically Conductive Adhesive (ECA) technologies to eliminate lead and further slash silver usage.
Strategic Trade-offs and Industrial Realities
A senior strategist must acknowledge that sustainability involves managed trade-offs. While Scenario 1 is high-performing, a fully “In-free” cell (Scenario 2) currently faces an efficiency gap of 1.2%, which remains a focus for optimization. Furthermore, reducing wafer thickness to 65 µm increases mechanical fragility, leading to higher breakage rates and a performance loss of up to 4.8% absolute compared to standard 165 µm wafers.
Finally, there is an economic circularity paradox: by removing silver, we reduce the “scrap value” of the module for traditional recyclers. This necessitates the development of new circular business models where the value is found in the high-purity recovery of silicon and glass rather than precious metal extraction.
Validating Success: Economic Impact and Technical Reliability
To ensure market adoption, RESILEX utilizes Life Cycle Assessment (LCA) and CoO analysis to prove that sustainability is economically viable.
Scenario 1 (S1) Performance Results
Comparative analysis of S1 (In-less/Ag-less) cells reveals:
- 10% reduction in total cell manufacturing costs.
- 42% reduction in mineral and metal resource consumption.
The Milestone 15 Demonstrator
The physical proof of concept is the “Milestone 15” demonstrator—a full-scale 60-cell module. This unit integrates TRL 7 In-less/Ag-less cells within a wooden frame, utilizing TPO encapsulants and fluorine-free backsheets.
Rigorous testing (Damp Heat, UV, Thermal Cycling) confirms that these designs meet international IEC standards. However, data indicates that “In-less” designs exhibit higher sensitivity to moisture ingress than standard HJT cells. This finding dictates that industrial-scale deployment must pair these cells with advanced, low-permeability packaging—such as the TPO and SiNx layers developed in the project—to ensure the 25-year durability expected by the market.
Future-Proofing: aligning with the European law
RESILEX proactively aligns with the EU’s Green Deal spirit, ensuring that European manufacturers are not caught off-guard by shifting mandates:
- ESPR (Ecodesign for Sustainable Products Regulation): By 2027, PV products must feature a Digital Product Passport (DPP). RESILEX’s focus on traceability and durability provides the framework for this mandatory disclosure.
- CRMA (Critical Raw Materials Act): The project’s success in slashing Indium and Silver use directly supports the EU goal of reducing reliance on third-country imports.
- NZIA (Net Zero Industry Act): RESILEX supports the target of meeting 40% of the EU’s annual solar deployment through improving domestic manufacturing by 2030.
- WEEE Directive: The move to non-crosslinking TPO encapsulants is a game-changer for recyclers. Unlike EVA, TPO allows for clean separation of components, enabling the industry to exceed current recovery targets (85%) by making high-value silicon and glass extraction technically and economically feasible.
The Roadmap to a Sustainable and Resilient Solar Future
The achievements of RESILEX in this specific domain, demonstrate that the perceived conflict between high performance and environmental sustainability is a false dichotomy. By re-engineering solar cells at the molecular level and modules at the structural level, we have produced a blueprint for a resilient European PV industry.
The roadmap ahead is focused on scale. We must now transition these validated TRL 7 strategies into mass production while deepening our end-of-life assessments to ensure 100% circularity. Through these innovations, Europe is not merely reacting to global market shifts; it is defining the new standard for a sustainable, sovereign, and resilient energy future.
Learn more
Factsheets
Factsheet #4 – Testing recycled silicon for PV applications
Factsheet #5 – BIo-sourced materials for producing new PV modules
Factsheet #6 -Driving down costs: eco-design innovations in silicon PV Cells for European Resilience
Factsheet #7 -Life Cycle Assessment for new and innovative eco-designed solar cells and modules
Deliverables
D4.2 – First report on bio-sourced materials & module components performance
D4.3 – Report of the CRM-free, low environmental footprint Si production cells
D4.4 – Roadmap for the eco-design of silicon solar cells & module technologies