For a bright and sustainable photovoltaic industry: recommendations to tackle end-of-life challenges

1 For a Brighter and Sustainable Photovoltaic Industry Recommendations to help tackle end-of-life challenges Lancaster Energy Rabia Charef, Bethan Jones and Ana Rute Costa 2 3 Solar panels don’t just deliver clean energy; they also have the potential to contribute to a more sustainable and circular use of materials. Striking the right balance between producing renewable electricity and managing resources wisely is one of the key challenges the sector must now tackle collectively to strive towards an all-encompassing vision of sustainability. 4 Authors Rabia Charef | Senior Research Associate | ERALD II Beth Jones | Research Associate | ERALD II Ana Rute Costa | Principal Investigator | ERALD II Technical Revision Alona Armstrong | Co – Investigator, Lancaster Environment Centre | ERALD II David Cheneler | Co – Investigator, School of Engineering | ERALD II John Fielden | Co – Investigator, Chemistry Department | ERALD II Industry Input Emma Silcocks | Bluefield | ERALD II Georgia Whitehouse | Bluefield | ERALD II Design, Production and Cover Ana Rute Costa Doi: 10.5281/zenodo.15971190 ISBN: 978-1-86220-434-8 First published: 2025 How to cite this white paper Charef, Rabia; Jones, Beth; Costa, Ana Rute (2025), For a bright and sustainable photovoltaic industry: recommendations to tackle end-of-life challenges, Lancaster University, doi: 10.5281/zenodo.15971190. The right of Rabia Charef, Bethan Jones and Ana Rute Costa to be identified as authors of this white paper, has been asserted in accordance with sections 77 and 78 of the Copyright, Designs and Patents Act 1988. The End of Renewable Asset Life Decisions II (ERALD II) research project was funded by EPSRC IAA at Lancaster University and Bluefield Solar Income Fund (BSIF), a FTSE 250 solar-focused investment fund. 5 For a Brighter and Sustainable Photovoltaic Industry Recommendations to help tackle end-of-life challenges Rabia Charef, Bethan Jones and Ana Rute Costa 6 7 Contents Preface Executive Summary Introduction Background Challenges and recommendations to help tackle end-of-life of PV panels R1 | Follow the circular economy principles R2 | Adopt digital materials passports to improve data standardisation and traceability R3 | Prioritise design for disassembly, reuse, durability and recyclability R4 | Mitigate early loss scenarios and extend lifecycle of materials R5 | Explore partial repowering and cannibalisation strategies R6 | Explore Reuse potential and second-hand market opportunities R7 | Develop of partnerships and second-hand market support R8 | Improve recycling processes and technologies R9 | Create specific regulations for PV panels R10 | Investment in research and knowledge exchange Closing remarks References 7 9 13 17 19 bbb 20 23bb b 26 bbb 29 bbb 34 bb 37 bbb 40 bbb 44 47 51 52 54 8 9 Preface The End of Renewable Asset Life Decisions (ERALD) research project was funded by EPSRC IAA at Lancaster University and Bluefield Solar Income Fund (BSIF), the first solar-focused investment company to be listed on the London Stock Exchange and a current member of the FTSE 250. This collaborative research partnership was formed in response to a growing need to identify responsible end-of-life solutions for renewable energy assets, with a primary focus on solar photovoltaic (PV) technologies. Initially focusing on the latter stages of the asset lifecycle, our findings revealed that the levers for transformative change span the entire supply chain; no single stakeholder can achieve this shift alone. This underscores the necessity for a holistic research approach that fosters collaboration among industry, academia and policymakers. Consequently, the research underpinning this white paper pivots from an ‘end-of-life’ perspective to a comprehensive focus on circularity. Our aim is to map current practices, identify systemic barriers, drive efficiencies, create value and uncover synergies with other environmental and social agendas. We propose a strategic roadmap for future research, innovation and policy engagement, to accelerate the shift towards a more circular solar industry. This white paper presents the outcomes of a literature review and industry consultation on current practices and challenges across the PV industry, highlighting potential solutions and providing recommendations for industry and policy makers. We delivered three focus group discussions and twelve semi-structured interviews, consulting a total of 33 UK stakeholders with wide-ranging expertise across the PV industry. We would like to thank all the stakeholders that anonymously contributed to this research and made this work timely, and essential to help move towards a more circular solar PV industry. Our primary focus is on Crystalline Silicon (c-Si) PV Panels, as they currently represent 95% of the PV market (Majewski and Dias, 2023). We will also present the opportunities for the transition towards a more circular PV industry and explain the lifecycle of solar PV panels from their production to reuse options before end-of-life. Indeed, c-Si PV panels dominate the market and have been associated with technical challenges with regards to recycling and other environmental impacts (Preet and Smith, 2024). These technologies can be complex and require effective recycling methods to 16 energy is expected to lead to significant economic opportunities, potentially generating £11 billion in economic value through recycling by 2050 ($15 billion) (Sulkan et al., 2025). Conjunctively, if we are to achieve net zero energy goals through increased PV deployment, we need to embed circular economy principles within the industry. Key materials used to produce solar PV panels are approaching critical scarcity levels and may be subject to commodity price fluctuations in the future (Bobba et al., 2020), creating an opportunity to salvage materials from old panels through recycling to recirculate in the manufacturing of new panels. However, there are still important challenges within the recycling of solar PV panels that need to be addressed. The process can be costly and energydemanding, largely due to the current design of panels that are not intended for easy disassembly. PV panel components are often tightly bonded, making it difficult to separate and recover valuable materials efficiently. By advancing recycling strategies and integrating design-for-recyclability principles, the solar industry can enhance material recovery, reduce resource depletion, and mitigate environmental risks, reinforcing its role as a long-term sustainable energy solution (Badran and Lazarov, 2025). There is an urgent need to reevaluate the design of solar panels making them easier to disassemble to support better recycling and reuse. (Lunardi et al., 2018) By emphasising recyclability, promoting second-life use, and enhancing material recovery, the industry has the opportunity to reduce its reliance on raw materials and its overall environmental impact. Experts emphasise that efficient recycling solutions could reduce future raw material strain and improve the use of currently available resources (Badran and Lazarov,2025; Herceg et al., 2022). However, it is important that a holistic approach to this evaluation is adopted, with due consideration given to achieving a balance between asset performance, durability and other environmental and social factors. Solar PV panels are one of the cleanest sources of electricity, presenting as a key step in the global energy transition towards achieving net zero energy goals. However, to strengthen the sectors’ sustainability, it needs to transition from a linear to circular economy (Chowdhury et al., 2020). The UK is in a strong position to lead the industry towards a circular economy. As of February 2024, there were 1,468,652 solar panel installations across Table 1 | Challenges that affect end-of-life of PV panels and recommendations to address them (table on page 11) (Source: Drawn by Costa, 2025) Stage of the lifecycle of PV panels R Transversal (T) T1 Waste generated throughout the PV panels’ lifecycle and end-of-life. T2 The PV panels with low quality have higher degradation rates. T3 There is a lack visibility/traceability across the PV supply chain: where/how materials are source and processed. T4 Lack of standardised Environmental Product Declarations. T5 The Solar Stewardship Initiative has still low adoption. Raw materials RM1 High social risks in material sourcing, e.g. Modern Slavery. (RM) RM2 The PV Industry is dependent on critical raw materials, e.g. silicon, silver, copper, aluminium. Manufacturing M1 Use of EVA and POE to seal and protect the solar cells: panel materials are (M) blended together = make disassembly and material separation difficult. 17 M2 Polymer backsheets contribute to early failure. M3 Technology discontinuity: replacement not possible if the panels are not available anymore. Distribution (Di) Di 1 If PV panels are damaged during transportation, are malfunctioning/defective, they are replaced and don’t go back to manufacturing. Construction (C) C1 Transport and installation damages: poor packing/stacking/forklift. Use and UM1 Absence of centralised spare parts hub. maintenance UM2 (UM) Early retirement of functional PV panels. UM3 Unbalanced supply/demand for available spare parts = over-replacement. UM4 Downtime risks due to poor spare parts management. UM5 Repowering with new, more efficient PV panels. UM6 Ownership changes hands quickly and is viewed as a future problem. Decomissioning D1 Lack of proper storage and no information about PV panels content. (D) D2 Lack of testing and recertification and reconditioning facilities. D3 Lack of spare parts due to rapid technology evolution. D4 High-cost reuse and recertification processes. D5 Lack of regulations and policies to support the development of second-hand market opportunities, e.g. reuse, recertification. D6 Stigma around second-hand PV panels: reuse avoided due to lack of guarantees and seen as lower quality. D7 WEEE directive is not specific to the PV industry and does not consider second-hand solutions. D8 Export risks: old PV panels becoming unmanaged waste. Recycling (R) R1 Recycling costs higher compared to landfill. R2 Lack of research into sustainable water treatment methods. R3 Use of chemicals during the recycling process: chemical methods are slow and costly. R4 Lack of more sustainable alternative substances to replace the use of chemicals during the recycling process. R5 Lower Global Warming Potential (GWP) for recycling compared to incineration and landfill. R6 Disparity between quantity of material, material recovery and material revenue: loss of material value through downcycling. R7 EVA is not recovered: the encapsulant layer is difficult to remove or use high temperature. R8 Thermal decomposition generates toxic gases. R9 Recycling facilities: the minimum annual waste volume required to be profitable: 20kt (Choi & Fthenakis, 2014). R10 PV panels are complex by design and difficult to disassemble. R11 Low purity of recovered materials. R12 Success measured by weight is misleading for solar PV panels: by focusing only on the weight parameter, we risk ignoring critical and valuable materials that exist in small proportions. R13 Around 90% of a panel’s weight comes from glass, aluminium, and plastic, which are easy to recycle but not the most valuable. R14 Small amount (less than 5%) of materials like silicon, silver, and copper that make up over 50% of the panel’s economic value. 1 R2 R3 R4 R5 R6 R7 R8 R9 R10 18 the UK (Milroy, 2025). With strong government targets for net zero, growing collaboration between research institutions and industry, and a policy focus on circular economy models, the UK can help drive innovation in sustainable PV panel design, reuse, and recycling. This white paper is the outcome of a collaborative project between academia and industry. It aims to explore the challenges faced by the solar PV sector and propose practical strategies for creating a more sustainable and circular PV industry. The background section of the white paper reviews the composition and production process of crystalline silicon (c-Si) panels, which continue to account for most PV installations worldwide. This provides the technical foundation for understanding the environmental impacts and opportunities for circularity. Next, we identified the main challenges that the PV industry face and provide 10 recommendations for government, industry and academia. In Table 1, we present the identified challenges in relation to end-of-life of PV panels. In blue we map the challenges being presented and discussed to inform the recommendations. In yellow, we map the challenges that can be addressed by the recommendations made throughout the paper. However, some of these challenges are highly connected and intertwined. This mapping exercise was created to help us understand how to address the current challenges and identify the priorities to tackle end-of-life of PV panels. 19 Background The composition of crystalline Silicon (c-Si) PV panels The composition of the solar PV module Silicon PV panels represent approximately 95% of the global PV market (Majewski and Dias, 2023), and the first generation of PV technology. As illustrated in Figure 1, they are typically made of seven layers. The glass, aluminium frame and encapsulant typically represent 90% of the material weight of the panel (Table 2). A recent study shows that in Europe, the dynamic material composition of PV panels has changed over time. For instance, the use of bifacial panels has led to an increase in glass content. In parallel, the silver, silicon, aluminium and encapsulant contents have tended to decrease (Figure 1)(Kastanaki, 2025). Figure 1 | The conventional crystalline-silicon PV module design (Source: Heath et al., 2020) 20 The solar PV panel lifecycle The process illustrated in Figure 3 is the solar PV lifecycle, from raw material extraction to end-of-life. The production of c-Si solar PV panels is often characterised as energy-intensive, particularly during the fabrication of silicon wafers, which requires substantial energy input (Saad, 2024). The production of polysilicon itself can also be extremely energy intensive, leading to a high carbon footprint (Huang et al. 2017). Throughout the slicing stage of ingots to produce wafers, there is often a loss of valuable material, with energy and resources expended in its production (Madrigal et al. 2023). Figure 2 | Accumulated amounts of silver, silicon, encapsulant, aluminium, glass (evolving material content) and Cu (fixed content) of c-Si PV panel waste under the Regular Loss scenario (Source: Kastanaki, 2025) Table 2 | Weight distribution of materials of a silicon solar panel according to Majewski and Dias (2023) Figure 3 | The solar PV panels lifecycle (Source: Drawn by Charef, 2025) 21 For a Brighter and Sustainable Photovoltaic Industry Challenges and recommendations to help tackle end-of-life of PV panels “A balance between materials purity, process complexity, and throughput” (SSI_02)1 22 R1 | Follow the circular economy principles Challenges R1 Recycling costs higher compared to landfill. R2 Lack of research into sustainable water treatment methods. R3 Use of chemicals during the recycling process: chemical methods are slow and costly. R4 Lack of more sustainable alternative substances to replace the use of chemicals during the recycling process. R5 Lower Global Warming Potential (GWP) for recycling compared to incineration and landfill. R6 Disparity between quantity of material, material recovery and material revenue: loss of material value through downcycling. The recycling of solar PV panels has a lower Global Warming Potential (GWP) of 48% compared to landfilling and 49% compared to incineration and the Human Toxicity Potential (HTP) is reduced by 85% (Khankhoje et al. 2025). According to Lim et al. (2022), the recycling process of solar PV panels has a lower GWP value at 25 kg CO2-eq compared to that of landfilling at 121 kg CO2-eq. Due to wastewater generation and the use of certain chemicals, processes involving chemical recycling techniques (particularly acid etching and the subsequent recovery of metal) may have a higher HTP and freshwater ecotoxicity potential compared to landfilling (Lim et al., 2022).Moreover, the non-chemical recycling techniques, such as mechanical and thermal techniques have also some limitations. Indeed, the thermal treatment method shows lower impacts on climate change, fossil fuel potential, water consumption, ecotoxicity, human toxicity, and particulate matter production, but it has more pronounced effects on ozone depletion and land use (Sulkan et al., 2025). Adopting more sustainable approaches for the management of end-of-life solar PV panels may be hindered by the recycling costs for some producers, around £14-£22 ($20-$30) for one panel, while landfill disposal is only £0.7 - £1.5 ($1-$2) (Okon Recycling, 2025). The collection cost of PV panels should also be considered, which may vary depending on the proximity of assets to recycling locations. 1 | SSI refers to Semi Structured Interview, the 02 means that this was second interview taking place during our data collection. 23 Recommendation 1 | Follow circular economy principles Promote industry accountability and circular practices: (1) Introduce clear regulations and targeted grants to mandate end-of-life planning and support circular practices across the PV sector, (2) Follow a revised waste hierarchy, adapted for PV panels, prioritising reuse, remanufacturing and refurbishment followed by recycling and energy recovery, (3) Consider decommissioning plans and circular strategies from the early stages of solar farm development, (4) Encourage multistakeholder participation in policy development, (5) Integrate the consideration of Environmental, Social and Governance (ESG) outcomes within end-of-life solutions, (6) Collaborate across the supply chain to drive efficiencies and enhanced transparency, accountability and value retention. According to Lim et al. 2022, the recovery of silver accounts for the highest proportion of generated revenue, despite its small amount (Figure 4). Following silver, the recovery of aluminium frames generates the second highest revenue. The recovery of plastic, silicon, and copper generates less than 11% of the revenue, while the recovery of lead, steel and aluminium hydroxide are less than 1% each (Lim et al., 2022). Figure 4 | Breakdown of revenue for the EOL solar PV panel recycling plant (Wei Lim et al. 2022) 24 The treatment of PV panels should follow the circular economy approach and waste reduction principles, focusing on the top of the “10 Rs waste hierarchy” developed for the construction sector (Vermeulen et al. 2019). Weckend et al. 2016, recommended to reduce the number of materials in new modules and increase their efficiency. Materials that should be reduced are silver, silicon, aluminium and encapsulants (Weckend et al. 2016). In the waste hierarchy in Figure 5, reuse of PV panels will save energy, avoid the extraction of natural resources and prolong the useful life of materials contained within them (Pareek, 2021). Reuse is very limited, and its adoption is facing many challenges. To ensure a circular approach Kastanaki and Giannis (2022) suggest locating the PV manufacturing facilities near recycling facilities (Kastanaki and Giannis 2022). By ensuring efficient recycling, the elements extracted from old PV panels could provide a significant portion of materials needed in the manufacturing of new panels. To move from a linear to a circular economy, the PV industry needs to follow the 10 Rs hierarchy to guide PV panel lifecycle strategies, in particular: • Reduce material use in new modules, especially high impact materials (silver, silicon, aluminium, encapsulant); • Reduce raw material use and keep material in a closed loop: use more recycled materials; • Promote reuse of PV panels to reduce raw material extraction and prevent waste; • Co-locate manufacturing and recycling facilities to enable efficient material recovery and reuse in new panels (close the loop); • Invest in efficient recycling processes to ensure high-quality material recovery; • Rethink the design of PV panels to make them easier to disassemble. Figure 5 | The waste hierarchy adapted from the Reike et al.’s model of the 10 Rs (Source: Drawn by Charef, 2025) 25 R2 | Adopt digital materials passports to improve data standardisation and traceability Challenges T3 There is a lack visibility/traceability across the PV supply chain: where/how materials are source and processed. T4 Lack of standardised Environmental Product Declarations. RM1 High social risks in material sourcing, e.g. Modern Slavery. RM2 The PV Industry is dependent on critical raw materials, e.g. silicon, silver, copper, aluminium. Environmental and social impacts in the PV supply chain In solving complex sustainability challenges, it is important to recognise and manage the broader positive and negative environmental and social impacts that may arise across the supply chain. Increasingly, companies are using sustainability-related data to measure not only their direct impacts but also those occurring within their supply chains (Alves and Steinberg, 2022). Taking this holistic perspective is intended to enable informed decision-making, ensuring that positive changes in one area do not inadvertently cause adverse effects elsewhere. For instance, like most mining activities, the extraction of silicon for solar PV panels is an energy-intensive process (Cristóbal et al. 2020). It can also be associated with social risks, such as modern slavery, as highlighted in by Cockayne et al. (2022). In addition, during the operational phase of solar PV farms, environmental factors must be managed, such as implementing effective land management practices to achieve an optimal balance between renewable energy production and biodiversity conservation (Copping et al. 2025). The need for transparency and traceability One tool used to communicate environmental impacts is the Environmental Product Declaration (EPD). An EPD is a third-party verified document that provides data on a product’s environmental performance throughout its 32 failure rates to more accurately predict when waste might be produced, to help inform end-of-life planning and recycling market development. These are known as Regular Losses and Early Losses. In the Regular Loss Scenario, it is assumed that PV panels reach their expected and manufacturer guaranteed 30-year lifespan with no premature retirement or failures. In the Early Loss Scenario, we consider premature failures, accidents, or early replacements, including all likely “infant”, “mid-life”, and “wear-out” failure possibilities, before the panel’s 30-year lifetime is up (IRENA-IEA 2016; Buehler, 2018). This reduced panel longevity has several potential causes, classified under 6 categories in Figure 7, and may lead to earlier volumes in PV waste being generated. Many of these early losses are preventable. Poor manufacturing quality Figure 7 | Early Loss Scenario Causes (Source: Drawn by Charef, 2025) 33 or unexpected rapid performance decline can result in early failure. Physical damage during transport, handling, or installation also contributes significantly. This may be due to rough handling or environmental exposure. In some cases, panels are not technically defective but are removed early because newer, more efficient models make older ones appear economically obsolete and may make more efficient use of available land area. Some sites could also be decommissioned because the model of PV panels installed is no longer available on the market. A lack of proper storage conditions and testing infrastructure further complicates efforts to assess whether panels can be safely reused. Invest in recycling facilities – second-hand market organisation Although many studies and reports have forecasted a large amount of PV waste, Nyffenegger et al., (2024) reported that the unpredictable volumes of materials available for reuse and recycling hinder substantial investments in the PV recycling sector. This uncertainty makes it difficult for both public and private stakeholders to commit to the long-term infrastructure needed for efficient recycling. In Europe, Germany and Italy will be the first countries to generate 20kt of PV waste annually (Choi and Fthenakis, 2014). Countries need to prepare themselves by investing in recycling facilities to be able to manage the amount of waste forecasted. Without such preparation, valuable resources may be lost, and waste management systems overwhelmed. Manufacturers are already working on their own recycling solutions, focusing on lead-free panel designs and promoting the recovery and reuse of materiails like silicon, silver, aluminium and glass. The aim of eliminating the use of lead is due to potential environmental and health risks at the end-of-life of the PV panels (Heath et al., 2020). Recycling old panels enables the recovery of valuable materials like silicon, silver or rare metals (rather scarce or difficult to extract), enabling a closed loop and a more resilient economy. While some of these materials may not currently have a high market value, they are finite and expected to gain strategic importance as demand for clean energy technologies increases. According to the IEA (2025), global demand for critical minerals used in solar technologies is projected to grow significantly, making early recovery efforts essential for future supply security. Therefore, if recycling techniques become more efficient, metals recovered from old panels could form a large portion of resources needed to make new 34 panels. Moreover, as suggested by Kastanaki and Giannis, (2022) and some interviewees, to ease the process, manufacturing plants could be located close to recycling plants to maximise efficiency. This co-location would reduce transportation costs and emissions while encouraging continuous feedback between manufacturers and recyclers. Figure 8 below, illustrates the key stages in the solar PV panel manufacturing process, based on interview analysis. It highlights four production phases: ingot pulling, cell production, module assembly, and final testing. While the process is highly efficient—with less than 1% waste during cell and module production—defective modules that fail testing are diverted from customer delivery. These modules, along with waste silicon generated earlier, represent key opportunities for material recovery through in-house or external recycling, or even the second-hand market where reuse is viable. Figure 8 | Waste generated throughout the solar PV panels manufacturing: from the ingot to the module testing (Source: Drawn by Charef, 2025, based on the semi structured interviews) 35 Recommendation 4 | Mitigate early loss scenarios and extend the lifecycle of materials Manufacturers and recyclers, supported by governments and research partnerships, should: (1) Explore synergies and opportunities for collaboration, e.g. establish feedback loops between different members of the supply chain to facilitate the identification of challenges and the development of potential solutions, (2) Establish shared recycling facilities, (3) Develop technologies to support reuse and recycling, (4) Suggest policy support for warranty tracking and predictive maintenance. “Instead of full asset repowering, companies can adopt partial repowering, using data to identify and replace only failed modules” (SSI_012) 36 R5 | Explore partial repowering and cannibalisation strategies Challenges UM1 Absence of centralised spare parts hub. UM2 Early retirement of functional PV panels. UM3 Unbalanced supply/demand for available spare parts = over-replacement. UM4 Downtime risks due to poor spare parts management. D3 Lack of spare parts due to rapid technology evolution. Avoid full repowering According to SolarPower Europe, some decommissioned PV panels are still functioning and can generate up to 80% of their initial capacity (SolarPower Europe, 2024). While repowering or revamping4 can improve the performance of solar farms, it may lead to the retirement of PV panels that are still functioning. However, there are arguments to suggest that this strategy makes the most efficient use of limited land area available to site utility scale solar farms. Some interviewees suggested to also consider partial repowering. Where possible, reuse options for decommissioned but functional panels should be prioritised, either within the same site or elsewhere. One practical approach is to create centralised spare parts centres, where panels can be stored and later used to replace defective modules, an approach often referred to as cannibalisation. This involves removing functioning components from one solar farm to use them as spare parts or replacements in another solar installation. PV panel technologies are rapidly evolving with some models discontinued, making it difficult to find replacement parts. The creation of a centralised digital spare parts hub would facilitate the maintenance and extend the life of solar assets by locating compatible spare parts. 4 | Repowering involves replacing outdated components of a solar PV farm, like panels or inverters to boost performance and efficiency. Revamping refers to repairing or optimizing existing equipment without full replacement, such as fixing wiring or updating monitoring systems. “Cannibalising still-functional modules to extend asset life is a costeffective and environmentally beneficial practice” (SSI_012) 37 Strategic repowering should aim to reconcile the need to improve energy efficiency with the objective of extending the lifetime of existing modules, reducing waste and supporting a more circular solar economy. Create a centralised spare part hub As solar PV technologies evolve, replacing defective modules can become challenging. Identical PV panels with the same physical and electrical characteristics may no longer be available on the market. This unbalanced supply/demand creates technical challenges that may lead to more equipment being replaced than is technically required. These challenges are a key reason why the creation of centralised spare parts hub could be a fundamental strategy. Spare parts are intended to replace similar items and play a key role in ensuring solar PV farms run smoothly. Their proper management is critical to avoid downtime. The location of the spare parts hub is also important, as it helps minimise transportation distances and associated emissions. According to SolarPower Europe (2021), commercial contracts often recommend stocking at least 0.2% of specific spare parts to support long-term operation. As shown in Figure 9, a centralised spare parts centre is a facility where solar panels that have been removed from service, but are still functioning, can be stored, tested, and reused. These hubs can act like “second-hand parts banks” for the solar PV industry, offering a reliable source of replacements for aging and damaged systems (Secondsol, n.d.). When combined with materials passports, these hubs can be managed more efficiently. Materials passports provide essential information about each panel’s specifications, condition, history and material composition. This enhances transparency and helps identify, track, and match decommissioned panels with reuse opportunities across solar projects. Technicians can quickly assess whether a panel is compatible with a given system, helping extend the life of solar components, reduce waste, and support a more circular solar economy. 38 Recommendation 5 | Explore partial repowering and cannibalisation strategies Manufacturers and recyclers should create research partnerships and business models to enhance material recovery rates and reduce waste. Supported by materials passports, the PV Industry should create a centralised digital spare part hub to facilitate the exchange of second-hand PV panels and extend the life of solar farms. Figure 9 | Waste generated from the module production to the end-of-Life (Source: Drawn by Charef, 2025, based on the semi structured interviews) 39 R6 | Explore Reuse potential and second-hand market opportunities Challenges T2 The PV panels with low quality have higher degradation rates. D4 High-cost reuse and recertification processes. D5 Lack of regulations and policies to support the development of second-hand market opportunities, e.g. reuse, recertification. D6 Stigma around second-hand PV panels: reuse avoided due to lack of guarantees and seen as lower quality. High cost of the reuse process and gap in regulations According to several authors and interviewees, the current reuse of PV panels is very limited (Radavicius et al., 2021; Van Opstal and Smeets, 2023). Due to the high cost of the reuse process, the eligible panels are typically those prematurely retired and in need of minimal repair before 11 years Peters et al. (2021) or 12 years for Kastanaki, (2025). Indeed, they need to be in good condition to be eligible for reuse (Freeman, n.d.) and handled by a specialised logistics company to ensure no damage occurs during transport. Both professionals in the field and researchers agree that there is a clear gap in regulations when it comes to certification standards, safety protocols, and warranty requirements for enabling a robust reuse pathway (Pareek, 2021). Poor quality of Solar PV panels Peters et al. (2021) suggest that panels with degradation rates exceeding 1.5% per year have limited remaining value and are unlikely to be viable for reuse, even at no cost. According to some authors, the standard efficiency degradation rate for PV panels is around 0.8% per year, under normal conditions (Hocine and Samira, 2019) while others reported a 0.7% efficiency degradation rate (Van Opstal and Smeets, 2023b). The authors highly recommend buying PV panels with better quality and durability, even if they are more expensive, as they will be able to produce more electricity and therefore revenue across their lifetime. “Reuse is currently limited due to handling damage, lack of certification, and low economic viability. However, emerging demand for reused panels exists, particularly in non-domestic applications’’ (SSI_011) 40 Cost of reuse: recertification process There are also legal issues preventing the refurbishment or reuse of operational second-hand PV panels, due to certification requirements, safety measures and warranty. Moreover, the recertification process is very expensive, which may impact the business case for reuse (for those buying and selling). The buyers of second-hand panels may want a warranty which would be difficult to provide. Recovered PV panels could generate extra income through reuse Regarding additional revenue streams, the sale of recovered PV panels for reuse could generate extra income for asset owners. Indeed, according to Pareek (2021) the profits gained by the seller of second life modules could become higher than the cost for recycling or landfilling. According to Kastanaki (2025), “If all waste is diverted to recycling, the gross value of recovered materials will reach £27 - £40 (€32-47) billion by 2050.” Under current conditions, a used panel sells for about 36% of the price of a new panel, while repair costs average £48 ($65) per module. After overcoming certification barriers, one-quarter of all PV panels reaching end-of-life by 2050 could be reused instead of being recycled or sent to landfill (NREL, 2021). Therefore, there are considerable opportunities in the investment of facilities aiming to extend the PV panels lifetime, whether for repair, reuse or recycling. Figure 10 | The reuse market challenges and opportunities according to the interviewees (Source: Drawn by Charef, 2025) “Companies should develop testing protocols and establish quality standards to expand secondlife markets” (SSI_011) 41 Reuse potentials Figure 10 gives an overview of the challenges and opportunities of reusing PV panels, extracted from the interviews conducted. Some of the items shown in Figure 9 are confirmed through existing literature. In Europe, instances of PV panels being transferred to LIC/NEEs (Low Income Countries / Newly Emerging Economies) have been noted in research (Pareek, 2021). Although this may be well-meaning (i.e., as part of social impact initiatives for communities without access to renewable energy), questions have been raised by the industry around whether donated PV panels will work and whether the countries they are being donated to have been supported with the necessary skills and infrastructure to operate, maintain, and dispose of them correctly (Kinally et al., 2022). Moreover, interview participants believe that there are several reuse potentials that could be considered, such as solar carports, domestic use, donation to communities, hospitals and universities. In terms of cost, the price of a second-hand PV panel has been assessed as approximately 70 % of the price of new panels (Weckend et al., 2016). Building trust in recovered solar PV panels through certification Despite the long lifespan and slow degradation of solar panels (less than 1% efficiency loss per year), their reuse faces challenges. Many older panels remain functional and could be reused (Deline et al., 2021), however the market for second-hand panels remains small. This is mainly due to concerns over quality, safety, and a lack of trust. Buyers often perceive reused panels as unreliable, even when their environmental value is high. To address these concerns, third-party certifications could play a crucial role by verifying product performance and safety. Re-certification, including checks for installation, maintenance, and efficiency, are essential for building trust. However, there are still no widely available standard processes for certifying reused panels (Tsanakas et al., 2020). Recommendation 6 | Explore reuse potential and second-hand market opportunities The PV Industry and governments should collaborate to facilitate second-hand market opportunities, (1) Develop reuse and repair infrastructure, (2) Expand upon reuse within the WEEE Regulations and create a specific standard for second-life PV panels, e.g. domestic use, (3) Create third-party certifications that can promote market transparency by confirming product quality, (4) Create financial incentives to stimulate the reuse market. 48 Summary The trade-off between durability and recyclability is a critical consideration in the lifecycle management of solar PV panels. On one hand, prioritising durability involves using materials like EVA/POE that enhance longevity and performance, enabling the panels to withstand harsh environmental conditions, thereby extending their operational life and reducing the frequency of replacements. However, panels designed for maximum durability often incorporate materials and construction techniques that are difficult to disassemble and recycle. This complexity can lead to higher costs and technical challenges in the recycling process, potentially resulting in improper disposal and the loss of valuable materials. Conversely, prioritising recyclability involves designing panels that are easier to disassemble and process at which could act to simplify the recycling process, reduce costs and improve the materials recovery rates. However, prioritising recyclability over durability may inadvertently increase the total amount of waste generated over the asset’s lifetime. To address this issue, a balanced approach is necessary. Policymakers and industry stakeholders should promote the development of innovative designs that optimise durability and recyclability, as well as recycling processes that seek to minimise adverse environmental impacts. Recommendation 8 | Improve recycling processes and technologies Invest in the current PV recycling processes and technologies to: (1) Minimise environmental impact and maximise material recovery rates, (2) Inform disassembly, reuse and recyclability, (3) Inform and support Extended Producer Responsibility (EPR) schemes. WEEE Directive recycling target: At least 85% must be recovered At least 80% must be recycled by weight 49 R9 | Create specific regulations for PV panels Challenges UM6 Ownership changes hands quickly and is viewed as a future problem. D5 Lack of regulations and policies to support the development of second-hand market opportunities, e.g. reuse, recertification. D7 WEEE directive is not specific to the PV industry and does not consider secondhand solutions. Success measured by weight is misleading for solar PV panels: by focusing only on R12 the weight parameter, we risk ignoring critical and valuable materials that exist in small proportions. R13 Around 90% of a panel’s weight comes from glass, aluminium, and plastic, which are easy to recycle but not the most valuable. R14 Small amount (less than 5%) of materials like silicon, silver, and copper that make up over 50% of the panel’s economic value. Regulatory Framework: Classification and inconsistencies The Waste Electrical and Electronic Equipment (WEEE) Regulations 2013 are the UK’s implementation of the EU WEEE Directive (2012/19/EU), which were designed to reduce the amount of electronic and electrical waste going to landfill and to promote reuse, recycling and recovery. Solar PV panels were officially brought under scope of these regulations in 2014. Post-Brexit, the UK has retained the WEEE framework and adapted it to fit domestic regulatory structures. Solar PV panels continue to fall under its scope. One interviewee explained “Under the WEEE regulations we have a treatment provider supporting the treatment and collection and the producer compliance schemes that report data to the Environment Agency and manage collections and treatment activities.” However, there is ongoing confusion around classification, particularly the distinction between Business-to-Consumer (B2C) and Business-toBusiness (B2B) waste. In the UK, most PV panels, although used in commercial solar farms, are currently treated as B2C waste. This classification subjects them to stricter and more costly recycling obligations. If these panels were correctly classified as B2B, they could be collected in bulk, tested, and reused more efficiently. “Advocate for Reclassification of solar panels under WEEE to reflect that most are B2B, not B2C, which affects funding and responsibility.” (SSI_011) 50 When classified as B2C waste, PV panels must undergo a stricter and more expensive recycling process, complicating their reuse or resale. Given that these panels usually come in bulk from solar farms being upgraded or repowered, reusing them is more practical, easier and cheaper. Incorrect classification can lead to improper recycling or unfairly shift recycling costs to other parts of the supply chain. Correct B2B classification would hold producers and large users more accountable and support better waste management planning. Policy and regulatory needs Stakeholders are calling for clearer and more supportive policies. Many interviewees highlighted the importance of broad stakeholder engagement with UK Government bodies (such as DESNZ and DEFRA - Department for Environment, Food and Rural Affairs). According to them, government policies play a crucial role in accelerating circular economy practices within the solar PV sector, not only by setting rules, but also by creating the conditions for long-term change. There is a real appetite for more structured and binding frameworks; many have indicated that in the absence of regulatory drivers, commercial incentives alone will not be sufficient in transforming industry behaviour. Although awareness across the sector is increasing, many stakeholders do not have robust plans in place for end-of-life of PV panels which may be in part, due to the short ownership cycles of solar assets. Stakeholders urged stronger legislation, mandatory circularity planning and targeted government grants. Several interviewees emphasised the importance of not only meeting recycling quotas but also ensuring that recycled materials are recovered to a quality suitable for reintegration into new manufacturing cycles. They also stressed the importance of policies that clarify the distinction between reuse and recycling processes, enabling businesses to make informed, low-risk decisions. While these measures are not yet mandated in the UK, they are seen by many stakeholders as essential to drive circular practices in the solar PV sector. The WEEE Directive: weight-based targeting The WEEE Directive, while valuable, is not “tailored” to PV panels. Interviewees pointed out that it lacks clarity on second-hand market development, reuse standards and recycling quality. Indeed, the directive currently uses weight-based targets to measure recycling success, which is problematic for solar PV panels. About 90% of a panel’s weight is made of “Advocate for Support for extended producer responsibility (EPR) models and leasing schemes (e.g., “pay-perwatt” models) to promote sustainable design and recovery.” (SSI_011) 51 glass, aluminium and plastic, having all low value compared to silver, copper and silicon that represent 5% of the weight but over 50% of the economic value (Figure 13). Therefore, if we seek purely weight-based recycling rates, we will continue to lose critical materials (Majewski and Dias, 2023). Recommendation 9 | Create specific regulations for PV panels Enhance the specificity of the WEEE Directive with PV-panel specific regulations: Policy makers should update/revise the WEEE Directive to make it more specific to PV panels and related regulations to: (1) Reclassify panels as business-to-business waste, (2) Require early end-of-life planning and support high-quality material recovery, (3) Enforce Extended Producer Responsibility (EPR), (4) Define standards for reuse versus recycling, (5) Create a regulatory and financial environment that encourages innovation in recycling and the growth of the second-hand market, without burdening compliance. Figure 13 | The PV Panels Weight Dilemma (Source: Drawn by Charef, 2025) 52 Figure 14 | Policy-related recommendations for Government, insights from interviews (Source: Drawn by Charef, 2025) Figure 15 | Policy-related recommendations for PV Industry, insights from interviews (Source: Drawn by Charef, 2025) 53 Solar panels don’t just deliver clean energy; they also have the potential to contribute to a more sustainable and circular use of materials (Lin et al., 2022). Striking the right balance between producing renewable electricity and managing resources wisely is one of the key challenges the sector must now tackle. R10 | Investment in research and knowledge exchange Recommendation 10 | Investment in research and knowledge exchange opportunities to tackle end-oflife of PV panels The UK government should provide targeted grant funding open to both academia and industry to research under three main categories: 1 - Materials (1a) The LCA of PV panels from extraction to disposal to enable the most sustainable solution to be identified: environmentally friendly, financially viable, socially equitable, (1b) Further advance recycling technologies to facilitate a circular economy and recover valuable materials; 2 - Systems and digitalisation (2a) Digitalisation of the PV sector by implementing material passports, developing systems using AI and digital trackers, (2b) Improved transportation, handling and storage of solar PV panels to avoid damage and early failure; 3 - Business models and design (3a) Alternative business models and markets, (3b) Alternative design of PV panels, considering Design for Disassembly. The PV industry and governments should provide worldwide standards, regulations, and policies that enable material custody throughout the supply chain and provide dedicated guidance for end-of-life solar assets. 54 Closing Remarks The Figure 16 presents a summary of the recommendations presented above and highlights in blue the circular economy cycle of the materials, prioritising design for disassembly, remanufacturing with recycled materials and reducing waste and downcycling where possible. The yellow lines show the importance of data transparency and accountability to inform the decisions throughout the lifecycle of materials. In white we explore potential reuse cycles of PV panels, and the light blue dashed lines highlight the need to recycle all the PV panels lost throughout the supply chain. Solar panels don’t just deliver clean energy; they also have the potential to contribute to a more sustainable and circular use of materials. Striking the right balance between producing renewable electricity and managing resources wisely is one of the key challenges the sector must now tackle collectively to strive towards an all-encompassing vision of sustainability. Collaboration between the PV industry, policymakers, and researchers is essential to implement these recommendations and unlock the full potential of solar as a resilient, sustainable energy solution for a brighter future. Figure 16 | Roadmap for the Photovoltaic Industry, recommendations to help tackle end-of-life challenges (Figure on page 53) (Source: Drawn by Costa, 2025) Roadmap for the Photovoltaic Industry Recommendations to help tackle end-of-life challenges PV Panels lifecycle to create a cicular economy Early loss recycling loops Digital Materials Passports Second-hand markets, e.g. domestic use, universities, hospitals, community hub The PV industry, government and researchers need to work together to achieve these recommendations. If we tackle the challenges that affect the end-of-life of PV panels now, we will be able to build a truly sustainable and brighter future. 1Recommendation 1 | Follow circular economy principles 2Recommendation 2 | Adopt digital materials passports to improve data standardisation and traceability 3Recommendation 3 | Prioritise design for disassembly, reuse, durability and recyclability 4Recommendation 4 | Mitigate early loss scenarios and extend lifecycle of materials 5Recommendation 5 | Explore partial repowering and cannibalisation strategies 6Recommendation 6 | Explore reuse potential and second-hand market opportunities 7Recommendation 7 | Develop partnerships and second-hand market support 9Recommendation 9 | Create specific regulations for PV panels 10 Recommendation 10 | Investment in research and knowledge exchange opportunities to tackle end-of-life of PV panels 8Recommendation 8 | Improve recycling processes and technologies 57 References Alves, R.-A., Steinberg, G., 2022. 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