Paul van Gerven
31 May 2022

Dutch company Solarge has fixed a major flaw in solar panels, which aren’t as sustainable as they can be.

These days, most solar panel manufacturers guarantee that their products keep operating at near-optimal productivity for 25-30 years. That’s quite an achievement when you think about it. How many electrical devices spend up to three decades outdoors, exposed to sun, rain and storm, without breaking down? That’s some impressive packaging! As it turns out, however, this lifespan-enhancing wrapping comes at a cost: recyclability. For as impressive as the lifespan of solar cells is, they don’t last forever.

Apart from the silicon cells, solar modules primarily consist of glass, plastic and aluminum. These three materials are all routinely recycled. Yet, this happens not nearly as much as you’d expect from an industry that prides itself on sustainability.

The reason is simple: it’s a pain to take the panels apart. The aluminum frame pops off relatively easily, but separating the remaining components is such a laborious process that it isn’t really worth the effort. Instead, the glass, silicon and other materials are sometimes ground into a coarse powder, which is then used as building material or abrasive. This so-called glass cullet isn’t worth much, however, and it’s unlikely there will be enough demand for it to ‘recycle’ all obsolete solar panels this way.

Dutch solar company Solarge has developed solar modules that are easily disassembled once they’ve reached their expiration date, making recycling a piece of cake. Additionally, by replacing aluminum and glass with plastics, Solarge’s panels are much lighter than current commercially available products. This enables installation on rooftops that can’t support the weight of traditional panels, greatly expanding the market potential.

Solarge recently found enough financial backing to start a manufacturing facility in the Dutch town of Weert. Initial production capacity will be 100 MW/year, with ambitions to scale up to 350 MW/year and beyond.

This 72-cell solar panel from Solarge weighs 14.5 kilograms, a conventional one about 25 kilograms. Credit: Solarge

Take the plunge

“Polymeric solar module materials have been a holy grail for a very long time. It took chemical companies decades to find plastics that can survive 25 years of exposure to UV radiation and heat,” says Huib van den Heuvel, chief commercial officer at Solarge. One solution, currently touted by most chemical companies, is to use fluorine-containing polymers. These PFAS materials are associated with major health and environmental concerns.

Saudi chemical manufacturing company Sabic went another way. Having developed a way to stabilize fluorine-free polymers, it worked with Dutch energy research institute TNO ECN to qualify the materials. At the same time, Sabic’s product sparked the interest of construction business Heijmans, which saw an opportunity for prefab composite rooftops with integrated solar panels.

Van den Heuvel had a front seat for all of this because at the time, he was director of the solar R&D outfit Solliance, of which ECN is a partner. Once all the boxes were checked – the technology proven and interest gained from a major company – Van den Heuvel, Heijmans CTO Gerard de Leede and experienced manager Jan Vesseur decided to take the plunge and start Solarge.

Negative footprint

Although the trio initially aimed at the prefab rooftops, they soon realized that their lightweight panels – about half the weight of their conventional counterparts – had additional potential. “As much as 45 percent of Dutch rooftops, including barns and warehouses, aren’t strong enough for regular solar panels to be installed on. That’s a huge market,” says Van den Heuvel.

On top of that, Solarge offers significant sustainability improvements beyond avoiding the use of PFAS materials. The modules are fully recyclable and circular, as a result of the module’s design-for-reuse, which in turn leans heavily on the characteristics of Sabic’s polymer material. Most plastics used in solar packaging are heavily cross-linked, meaning the molecular strands have been linked together. This results in a more sturdy, less water-permeable material, but also one that’s very hard to recycle – cross-linking is basically an irreversible process, making the separation of silicon cells and encapsulating materials of an end-of-life module a tough nut to crack. Hence the shredding.

Sabic’s material, on the other hand, isn’t cross-linked. Cells and polymeric layers let go of each other simply by heating, making both of them available for recycling. “The backsheet can be recycled as is; it doesn’t matter what it looks like. But the characteristics of the front-side polymer, in particular transparency, have to be restored. And that’s no problem, using a chemical recycling process for which Sabic is currently expanding its production capacity,” explains Van den Heuvel, adding that there are promising indications that recycling of solar silicon will be possible in the near future as well.

Even before considering recyclability, Solarge’s modules feature a significantly lower carbon footprint than conventional modules. “That’s the result of polymers being less energy-intensive to manufacture and process than aluminum and glass. Just by replacing these materials, our carbon footprint drops 25 percent. But we want to go lower, much lower. We plan to substitute the Chinese cells that we currently employ with European ones that are manufactured using sustainable energy sources. That would cut our current footprint in half. Eventually, using biobased or recycled polymers, we could even achieve silicon solar cell packaging with a negative footprint.”

Missing the point

Solarge won’t be able to compete on price for a few years. Its modules aren’t inherently more expensive, but the company simply lacks manufacturing scale. Betting on customers willing to pay a premium for its lightweight and recyclable solar cells, as well as the introduction of new EU sustainability standards and carbon emission taxes that will discourage less sustainable PV imports from China and other Asian countries, it expects to quickly expand capacity. Van den Heuvel estimates that his company will reach price parity with conventional modules at a manufacturing capacity of 1 GW/year.

Isn’t there an elephant in the room, however? Thin-film solar cells haven’t been widely adopted yet, but once they are, they should be fierce competitors for Solarge’s product. After all, they’re also lightweight and they also require much less energy to be manufactured. That’s missing the point, says Van den Heuvel. “Our core business is packaging technology, it doesn’t matter for what kind of cells. We’ll gladly embrace thin-film PV when that comes along – that needs packaging, too.”