Giving solar panels a second life

The sun is setting on a generation of solar panels. Since the late 1990s, the need to find ways of generating electricity without burning fossil fuels has led to rapid growth in the use of photovoltaic panels, both on a domestic scale (on rooftops) and industrial (generally in fields). Their use has increased significantly since 2010, when financial incentives came into force to encourage their uptake. This included energy companies offering free panels to homeowners under the Feed-in-Tariff scheme, where they would be paid for electricity generated.

In the UK, total installed capacity for photovoltaic solar power reached 18.9 GW peak capacity in May 2025, according to the Department for Energy Security and Net Zero, providing just over 5% of total electricity generation – a proportion that has risen from just 0.01% in 2008. In terms of area, the government estimates that 21,200 hectares of land were covered by solar panels in the UK in September 2024 (2,120 million square metres) – about 0.1% of the total land area in the country. Worldwide, solar generation capacity reached 1062 GW in 2022.

But these impressive figures mask a looming problem. Solar panels’ performance declines over time, due to factors such as long-term exposure to UV rays and weather, with most having a 25- to 30-year useful lifespan. This means that a substantial proportion of the installed panels across the country are approaching the end of their life.

In the UK, end‑of‑life solar panels are not automatically treated as hazardous waste, but they are regulated. Under UK law, they are classified as electrical and electronic equipment (EEE), which means that once they reach end of life, they fall under the Waste Electrical and Electronic Equipment (WEEE) Regulations. This classification places legal duties on producers and waste handlers to ensure they are properly collected, assessed and recycled.

As their use continues to grow, solar panels are forming part of a rapidly increasing e‑waste stream and without coordinated regulation and treatment capacity, valuable materials could be lost and environmental risks could rise. 

This has focused attention on the possibility of recovering valuable materials from discarded solar panels and recycling or reusing them. In 2024, the Exeter Centre for Circular Economy (ECCE) at the University of Exeter produced a report, From Linear to Circular: Evidence from the UK solar sector, that explored the continued use of solar panels and their component materials after they reach end of life. One of the report’s co-authors, Professor Peter Hopkinson, sees the issue as part of a wider problem of e-waste: the UK needs better systems for collecting, testing and recycling end‑of‑life solar panels at scale. “We are facing, yet again, another challenge with products, components and materials that have been placed on the market where we don’t have infrastructure or regulations that can manage end of life in a coordinated way. So, we’re not capturing the maximum value from those products. Rather like electronic components generally, we’re facing a messy and complex situation, and it’s going to get worse.”

By 2030, according to ECCE, an estimated 82 million tonnes of e-waste per year will require safe disposal in the UK, of which some 30,000 to 200,000 tonnes will be solar panels – potentially reaching 1.2 million tonnes by 2050. The materials that make up the majority of a typical panel’s mass are aluminium, used in the frames; critical minerals such as copper and silver, used in the electronics; and the glass that comprises the panels’ outer surface. If these materials can be extracted from the solar panels and purified, they can be sold to manufacturers for reuse in new products: copper and silver are in high demand for electronics, although are difficult to recover because of the small percentages; aluminium is used in many sectors, notably aerospace and general manufacturing; and clean glass is, of course, readily recycled. Despite this, however, some of the concern over solar panels focuses on materials used in their electronics and the photovoltaic cells themselves, such as crystalline silicon and rare earth minerals, which have limited global supply.

ECCE sees making solar panels part of a circular economy largely as being a matter of design, ensuring that the components of panels can be separated easily for repair (if possible) or disassembly to recycle their constituent materials. “Modularity is the first thing to think about,” says Diego Bermudez, a research and impact fellow at ECCE who has worked on data modelling for several circular economy projects. “But you also have to think about the materials you use and minimise those that are difficult to recycle or reuse.”

Extracting the materials

In cases where the solar panels cannot be repaired or reused, engineers are working on ways to extract and recycle the material components. One such process is flashlight delamination, which uses short pulses of high-intensity light to separate the layers of polymer composite: the light pulses heat up the materials, causing their layers to separate. The process, along with disassembly steps, separates solar panels into glass, aluminium, polymers, silicon, and metals such as silver, in a form that can be sold to manufacturers and reused in other products. Dresden-based Flaxres is one company using this technique. Its mobile recycling plant for solar panels travels to where the panels are decommissioned, saving on transportation costs. With a capacity of 10 tonnes per day, Flaxres claims the plant can recycle 95% of materials in the panels. 

Photorama, an EU-funded project that involved companies from Spain, France, the Netherlands, Sweden, Germany, and Italy, concluded in early 2025 with the opening of a pilot plant in Tangermunde, Germany. Similarly to Flaxres, the plant incorporates flashlight delamination, alongside processes such as diamond wire cutting; water jets to separate polymers and solar cells; solvent extraction with an ethylene glycol/calcium chloride mixture followed by electrolysis to recover silver and silicon; and a similar extraction/electrolysis process with methane sulfonic acid for indium and gallium. According to project coordinator Claire Agraffeil, one of the project’s biggest achievements was coping with the diversity of design in the solar industry and across several different countries. “It may seem easy, but there are over 150,000 models of photovoltaic devices, with their own design specifications, so it is very complex to find a universal way of disassembling them. We had to design and develop a whole system, flexible enough to treat any kind of photovoltaic waste. It is very important, because recycling is about throughput and high-volume treatment.”

Although recovered glass, aluminium and silicon can be readily reused across a range of applications, it is the conductive metals that represent the most valuable resources contained within end-of-life solar panels. These essential materials are crucial for clean energy technologies, yet their supply remains constrained and vulnerable to disruption. By recycling spent panels and recovering these critical metals, the industry can help to mitigate supply risks, reduce reliance on raw material extraction, and support a more resilient supply chain for renewable energy technologies.

France-based ROSI Solar, claims to have developed the first process to recover pure silver from spent solar panels. It uses a thermal delamination process – high heat in the absence of oxygen that breaks materials down into a mix of gas, liquid and solid char, often used in plastic recycling – to separate the constituent materials, then further treats the products of pyrolysis with water-based chemistry to extract and purify copper and silver for sale and reuse. Its plant can process 10,000 tonnes of panels per year and although the mass of metals recovered is small – a little over 40 tonnes of copper and 8 tonnes of silver per year – this represents a large fraction of the value of the panels, where over 60% of the material value is embodied in just 3% of the total mass.

The possibility for recycling doesn’t just stop with the panels themselves; the solar sector can also be a customer for recycled material – including those recovered from spent panels – making it a potential contributor for a wider circular economy. Researchers at Newcastle University are working with the Ministry of Defence and a Norwegian company, Wastefront, to use carbon black, a pigment that can be made from waste tyres, in printable light-absorbing inks that can be used in photovoltaics. The project found that the ink performed as well as a product made with virgin carbon black.

Steps towards a circular economy

While innovative ways of recycling and reusing solar panels are paving the way towards a more sustainable and circular economy, it is clear that further action is needed from both industry and government. Stronger policies, increased investment, and collaborative efforts are essential to scale up such solutions and ensure their widespread adoption, ultimately maximising the environmental and economic benefits for society.

Recycling is a first step and to make it more efficient, the ECCE report encourages manufacturers to publish lists of all the materials in their products, highlighting anything hazardous and making it easier to track the impact of the products on the environment. Government policy should also encourage investment in developing recycling facilities specifically for solar equipment, while industry should establish testing facilities to identify equipment that can be reused rather than scrapped and formulate standards for photovoltaic reuse.

Business models that extend the lifespan of functional panels through repair, maintenance and reuse, and improved data collection on system performance and failure cases can also help to effectively manage the growing challenge of solar waste. Such insights will be crucial for refining panel design, shaping better regulations and supporting the shift to a more circular economy in the industry.

The future sustainability of the UK solar industry depends on embracing circular economy strategies that prioritise ongoing use, robust repair, and effective recycling of the materials that make up the panels, supported by transparent information and progressive policies. This approach will help retain the value of solar technologies, reduce environmental impact and ensure the sector’s continued growth.

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Stuart Nathan would like to thank Ananda Nidhi, the lead researcher of the From Linear to Circular report; Dr Kiran Gulia of Green Loops; Claire Agraffeil of Photorama; and Pablo Dias from SolarCycle for their help in producing this article.