The next generation of solar panels is not only more efficient, but also cleaner, circular and less reliant on raw materials from outside Europe. These are not mere side issues for Europe’s strategic position. They are prerequisites.
Solar energy is the backbone of the Dutch energy transition. Every year, hundreds of thousands of new panels are installed on the roofs of homes and businesses, and in large ground-mounted arrays. At the same time, the first generation of panels is reaching the end of its technical lifespan.
This development presents the sector with a broader challenge than simply scaling up. It is not just about more solar panels, but about better solar panels: panels that are less dependent on scarce raw materials, can be recycled to a high standard and meet Europe’s requirements for a future-proof energy supply. After all, today’s choices regarding materials and design determine not only the environmental performance of panels, but also their processability, residual value and sensitivity to changing regulations.
This means that sustainability, economic viability and strategic autonomy are directly interlinked. Many panels that are still considered the market standard today are, in essence, designed on a linear basis: they are difficult to recycle to a high standard, rely on raw materials and supply chains outside Europe, and are not without future regulatory risks. It is precisely here that the tension is growing between the rapid roll-out of solar energy and the framework conditions needed to ensure that growth remains sustainable in the longer term.
How can you get the most out of the panels that are already in place? And how can you ensure that new panels are better aligned with the needs of the energy transition from day one: clean, circular, economically sustainable and less reliant on supply chains outside Europe? To answer these questions, TNO is working with partners on two fronts.
The first track focuses on the existing fleet: millions of panels that will eventually be replaced and from which valuable raw materials must be recovered. Raw materials that would otherwise be lost, have to be re-imported, or end up as waste.
The second track looks to the future: how can solar panels be designed so that, right from the start, they meet tomorrow’s requirements, are free from harmful substances, are recyclable by design, and are manufactured in Europe?
The two approaches are inextricably linked. Recycling technology is essential for the existing fleet, but ensuring that future panels do not cause the same problems is the most sustainable step. TNO and its partners are achieving concrete results on both fronts.
Solar panels are designed to be so robust that they last for decades, but this is also their weakness when it comes to recycling. Glass, solar cells and protective layers are bonded together with powerful adhesives. Current recycling methods are therefore often crude: crushing or heating, followed by processing into building materials for use in road surfaces or bridges, for example. This results in the loss of valuable materials. Alternative recycling methods that aim to recover materials often consume an excessive amount of energy.
The economic logic is clear: by 2024, around 24 per cent of the silver mined worldwide was already being used in solar panels. Since then, the amount of silver used per panel has fallen, but it still accounts for a significant proportion of global silver consumption due to the growth in production. If this raw material is discarded on a massive scale as waste, an unnecessarily large amount of economic value will be left untapped.
Silver, as well as the silicon used to make the solar cells themselves, are also scarce raw materials. Recovering them is therefore essential, particularly as global demand is rising sharply. The growth of solar energy and other applications is putting pressure on their availability. This is precisely why it is crucial to keep these raw materials in the cycle as much as possible.
TNO therefore developed a fundamentally different approach to recycling: a laser technology that selectively breaks the bond between the various layers in the solar panel without damaging the underlying materials. With an expected recovery rate of 99 per cent for silver, whilst using only a fraction of the energy consumed by existing methods, recycling is transformed from a cost centre into an economically attractive source of raw materials.
“By 2030, we expect to see a significant wave of end-of-life solar panels in Europe. That is not a waste problem; it is an opportunity for raw materials.”
Mirjam Theelen, head of research at TNO
What exactly is in the standard panels currently installed on most Dutch roofs? The answer has both economic and strategic implications, and it is less reassuring than the sector generally acknowledges.
In addition to the silver and silicon mentioned above, a typical solar panel consists of glass, an aluminium frame and plastics (packaging). The aluminium frame is fairly easy to recycle, and this is already being done on a large scale. The situation is different for the glass and plastics.
The vast majority of these panels are made using glass sourced from China. That glass, which accounts for around 70 per cent of a panel’s weight, contains antimony: a toxic heavy metal that is added to molten glass to remove air bubbles and produce a transparent and clear glass mass. This refining process is essential for the quality of this special glass used in solar panels, but at the same time it makes the end product problematic.
Antimony is harmful to humans and the environment and is classified as a critical raw material, the extraction of which is heavily concentrated outside Europe. This makes it a challenge to recycle the glass on a large scale to a high standard at the end of its life, and in practice it often ends up in lower-value applications, for example in the construction industry as fill, insulation or foundation material. Consequently, some of the material’s value is inevitably lost. Each panel contains, on average, tens of grams of antimony.
Alongside antimony, PFAS play a role in the debate on sustainable solar panels. PFAS, known as ‘forever chemicals’ because they hardly break down at all in the environment, are used in the protective plastic coatings of solar panels. Which coatings these are depends on the panel’s construction.
A REACH restriction process aimed at banning PFAS in solar panels has been underway within the EU since 2023, and is now approaching its final stage. For parties currently investing in PFAS-containing panels, this poses a regulatory risk with direct financial consequences.
The choice of materials during the design phase therefore directly determines how easily a panel can be recycled, what regulatory risks it entails, and the extent of its dependence on external raw material supply chains. These are not technical details. They are economic and strategic choices.
Whilst TNO is working on improving the recycling of currently installed solar panels, the development of a new generation of panels that tackles these problems at source is taking place in parallel. “Circular by design”, right from the first day of production. This track has two levels: what is already available today, and what is coming in the near future.
A striking example of how this is already available comes from Solarge, a Dutch manufacturer with a factory in Weert, Limburg, which is already marketing lightweight solar panels that are completely free of PFAS and antimony, thereby staying ahead of forthcoming European regulations. The panels are made of plastic rather than glass, which makes them about half as light as conventional panels.
This makes them suitable for roofs that cannot support the weight of traditional panels – a category estimated to cover an area comparable to that of all the solar panels installed in the Netherlands to date combined.
The panels are designed to be fully circular: at the end of their life cycle, the recovery of materials generates revenue rather than costs. Solarge offers customers a take-back guarantee, with circularity as a business model rather than a marketing claim.
The laser technology has been demonstrated to work on a full-scale basis. As part of the CVER project (Circular Processing of Solar Panels), TNO applied the laser technology to complete modules from Solarge, lightweight solar panels made of plastic, completely free of PFAS and antimony. This project also involves collaboration with another partner in the supply chain, the recycling company MIREC.
The results show that circular design and high-quality recycling reinforce one another. The following was achieved when dismantling the Solarge modules using laser technology:
The PFAS-free plastic backsheet (polypropylene reinforced with glass fibres) could be removed, reused and relaminated without any problems, providing a direct demonstration of a closed-loop material cycle.
The polymer front sheet could be easily removed from the module after laser processing and gentle heating, without damaging the underlying layers.
More than 99 per cent of the wafer material was recovered, with a purity of over 99.9 per cent.
Although Solarge panels are, by design, exceptionally low in silver – which in itself is a sustainability benefit – initial tests have already shown that 93 per cent of the silver present was recovered with a purity of over 96 per cent.
Smartly designed panels are also easier to recycle. The results prove that this dual approach works: better materials at the outset mean better returns at the end of the product’s life, and thus lower total system costs over the entire life cycle.
The next step is solar panels made not from silicon but from perovskite.
TNO has observed that many organisations around the world are investing in a new type of solar cell technology: perovskite solar cell technology, often mounted on glass.
Unlike many other organisations, TNO has made a conscious decision to opt for roll-to-roll technology using flexible films, drawing on the knowledge and experience within the Dutch ecosystem. Applications for the end product range from lightweight, bespoke films that generate solar power to lightweight, circular solar panel technology using polymers, as demonstrated by Solarge.
TNO and Solarge have already jointly developed a prototype perovskite solar panel using a unique polymer structure – a world first for the Netherlands that combines these two innovative technologies. The light-absorbing layer is produced using TNO’s roll-to-roll manufacturing process for perovskite, in which solar cells are manufactured, as it were, on a conveyor belt, similar to the printing of a newspaper. Solarge provides the expertise for the plastic structure surrounding these cells, using the same approach as in their existing panels: lightweight, circular and glass-free.
An additional challenge in this regard – which various parties are working on in collaboration with TNO, amongst others – is to ensure that this plastic structure remains PFAS-free. A great deal of research is currently being carried out into the effectiveness of these layers, taking into account costs, availability and certifiability. The prototype already demonstrates that the combination of these technologies is, in principle, suitable for the transition to multi-layer perovskite solar cells, with CO₂ emissions expected to be less than 10 grams per kilowatt-hour – a fraction of those from conventional solar panels.
Solarge and TNO are working on plans to develop the technology into a fully-fledged product as quickly as possible, with support from the SolarNL Growth Fund project.
“This will make the Netherlands a world leader in sustainability, and in the long term, price breakthroughs are also possible.”
Gerard de Leede, CTO at Solarge
A sustainable energy supply chain, in which we produce renewable energy to meet our own needs, makes the Netherlands and Europe resilient in economic, climate-related and political terms. Anyone wishing to use solar energy as the foundation of the energy transition must also consider the supply chain behind those panels. Europe is currently heavily dependent on components from China, ranging from glass to rare earth elements. This dependence makes the energy transition structurally vulnerable: to price fluctuations, geopolitical tensions and supply risks.
The innovations being developed by TNO and its industry partners offer a counterbalance on each of these fronts. Perovskite technology can be produced locally using materials that are largely available in Europe. Lightweight plastic modules reduce dependence on Chinese glass. Circular material and design choices make the panels future-proof. Advanced recycling technology keeps valuable raw materials within the European supply chain. And a growing European manufacturing sector centred on new PV technologies increases the strategic freedom of choice for policymakers and industries.
Strategic autonomy in energy is not an ideological stance. It is an economic prerequisite. Whoever controls the supply chain also controls the costs and the continuity of the energy supply.
The energy transition will only succeed if it is both economically viable and strategically sound. This requires more than simply installing more solar panels. It requires panels that ease the strain on the raw materials supply chain rather than adding to it, that can be recycled without losing value, and that make Europe less dependent on supply chains outside the continent.
TNO is working on both fronts: on advanced recycling technology that recovers valuable raw materials from existing panels, and on a new generation of technology that tackles these problems at source. From circular plastic panels already installed on Dutch roofs today to perovskite solar cells produced on a conveyor belt, from bespoke solar film to closed-loop material cycles: the technology to make the solar sector future-proof is under development, and is already partly available.
The next generation of solar panels isn’t just more efficient. They’re cleaner, more circular and strategically sounder. And they’re closer than you think.
Link to the original article: Solar energy of the future: cleaner, circular and European
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