Wanted: A System for Longer Solar Panel Life

Solar energy is growing steadily in Sweden – but the way we handle solar panels is still largely linear. A new systems analysis within CircSolar shows that significant resources risk being lost when panels are taken out of use – but also that there are strong opportunities to create a more circular system.

Today, solar power accounts for 4.5 percent of global electricity production, but it’s expected to become the largest renewable source by 2029. At the same time, more than 100 million tons of solar panel waste are projected to accumulate worldwide by 2050 – representing a material value of over 150 billion dollars.

In Sweden, the solar panel market is growing. In 2024, 41,400 installations were connected to the electricity grid, with a total installed capacity of 847 MW. Today, solar power accounts for around two percent of Sweden’s electricity mix. The challenges related to end-of-life panels are still minor, but the volumes are expected to increase significantly in the future.

Everything Becomes Electronic Waste

At present, end-of-life solar panels are largely handled together with other electronic waste, meaning they are included in the same broad waste stream governed by the requirements of the WEEE Directive (Waste Electrical and Electronic Equipment). Under this European regulatory framework, the waste stream must be processed so that at least 80% of the materials are recycled, with the intention that these materials are recovered in a way that enables their use in new products.

However, the flow of solar panels entering this waste stream is far from homogeneous. It consists of both new and old panels, functioning and non-functioning, which today end up in one of four treatment pathways: material recycling, energy recovery, landfill, or export. As a result, they are often processed in systems that are not always adapted to the specific materials or construction of solar panels.

As the volume of solar panels reaching the waste stream increases, so does the need for new and more specialized recycling technologies. To meet the goal of 80% material recycling set out in the WEEE Directive, new collection and recycling lines specifically designed for solar panels are therefore gradually being established across Europe.

We’re seeing many different types of decommissioned solar panels that leave the system – from unsold inventory and transport damages to functional.

– Beatriz Pérez Horno, researcher in circular economy at KTH Royal Institute of Technology.

– We’re seeing many different types of decommissioned solar panels that leave the system – from unsold inventory and transport damages to functional, yet slightly degraded, panels replaced prematurely during so-called repowering. Many of these panels still work, and in some cases, they are completely unused, but today there are no markets in place to favor their reuse, says Beatriz Pérez Horno, researcher in circular economy at KTH Royal Institute of Technology.

Unsold Stock and New Initiatives

An unexpected insight from the CircSolar project’s systems analysis is how many solar panels never even reach installation. Consumers tend to prefer the latest models, which means that older panels risk remaining in storage.

To address this, the solar energy company Svea Solar has tested an offer allowing customers to purchase older models at a lower price.

– In this way, we can make better use of available resources while offering our customers a more cost-effective option, says Alison Wren, Head of Residential Hardware at Svea Solar.

This demonstrates that the industry can already take steps to reduce resource loss – even within today’s linear system.

Repowering: When Functioning Panels Are Replaced

The analysis also shows that rapid technological development and falling prices create a risk that many solar panels are replaced prematurely, even though they are still functional. This phenomenon, known as repowering, means that working panels are replaced with newer and more efficient technology. This presents a clear sustainability challenge, as there are currently no effective ways to extend the lifespan of used panels. As a result, fully functional solar panels may go straight to recycling – a process that is inefficient from both a resource and climate perspective.

With a theoretical lifespan of around 30 years, it would be more resource-efficient to keep panels in use longer, rather than replacing them after just 10–15 years.

The most advantageous option is to let the panels remain in their installations for as long as possible. When they do need to be replaced, a functioning second-hand market would be a far better choice than sending the panels straight to recycling.

Today, however, that market remains weak. This is due to a combination of rapid technological development, falling prices for new panels, high handling costs, and a lack of effective systems for the collection, testing, and quality assurance of used panels.

If there were effective systems for take-back, testing, and certification of used panels, we would gladly explore how they could be resold.

– Alison Wren, Head of Residential Hardware at Svea Solar

Taken together, these factors make it difficult for used solar panels to compete with new ones in today’s system. For reuse to become a realistic option in the future, a cost-effective handling is required, and solutions that create confidence among customers. Or, as Alison Wren puts it:

– It’s important that panels meet high standards of quality and safety. If there were effective systems for take-back, testing, and certification of used panels, we would gladly explore how they could be resold.

Design Challenges and Upcoming Requirements

Today’s solar panels consist of about 60–67 percent glass, 16 percent aluminum, 11 percent plastic, 4 percent silicon, and around 1 percent metals such as silver and copper. Yet materials and quantities vary from model to model. At the same time, problematic substances like PFAS and antimony are present – making circularity and recycling more difficult.

This is where the EU’s new Ecodesign for Sustainable Products Regulation (ESPR) and upcoming Digital Product Passports could play a crucial role.

– To advance the circularity of the system, data transparency and proper recording of the materials, designs, and models of panels being imported and deployed is crucial. Digital product passports have been on the table for a while, but putting these measures in place takes time, says Beatriz Pérez Horno.

Recycling – A System in Development

At present, there is no specific waste code for solar panels, which means they may end up being mixed with all other electronic waste. The research institute RISE and the Swedish Energy Agency have therefore recommended that solar panels be given their own waste category. This would make both recycling and data collection easier.

We’ve tested advanced recycling methods in the Netherlands with good results and expect to invest in a dedicated recycling line in Sweden as volumes increase.

– Sven Jonsson, Technical Advisor at the recycling company REMONDIS

– The glass, which makes up 60–70 percent of a panel, is particularly challenging. It’s unclear whether it can meet the high-quality requirements demanded by the market. We’ve tested advanced recycling methods in the Netherlands with good results and expect to invest in a dedicated recycling line in Sweden as volumes increase, says Sven Jonsson, Technical Advisor at the recycling company REMONDIS.

When Will the Volumes Come?

Analyses of future waste volumes within the CircSolar project show that the amount of end-of-life panels is expected to increase faster over the next 5–10 years than previously predicted. The reason is that many of the early installations are now approaching the end of their lifespan – and repowering could accelerate this development even further.

– Just because we haven’t yet seen the large volumes doesn’t mean they aren’t about to arrive. Circularity requires us to act proactively rather than reactively. We need to have solutions and plans in place before we find ourselves facing piles of discarded panels with no clear strategy for handling them. Otherwise, there’s a real risk that suboptimal measures will be taken and valuable resources will be lost, emphasizes Beatriz Pérez Horno

Next Step: A Circular Roadmap

With a clearer understanding of how today’s system operates, the CircSolar project is now ready to take the next step – to develop a circular roadmap for solar panels in Sweden. It will guide the transition toward a more resource-efficient and circular management of solar panels throughout their entire life cycle.

This gives us a strong foundation as we take the next step toward a shared roadmap.

– Johanna Olofsson Behrman, Project Manager Future Materials, Axfoundation

– Through collaboration across the entire value chain and KTH’s systems analysis, we’ve gained valuable insights into how solar panels can be managed more sustainably. This gives us a strong foundation as we take the next step toward a shared roadmap, concludes Johanna Olofsson Behrman, Project Manager at CircSolar.