The race to solve solar energy's recycling problem

"We might have a teeny tiny problem with solar. And it’s not that they don’t produce energy at night. " What started delivering clean energy in the 1950s and took off in the late 2000s "…is now ready for the dumpster.

Not because the technology is trash, but because solar panels are built to last between 20 to 30 years. " Soon we could be looking at 27 million tons of out-of-date solar waste. And only a tiny fraction gets recycled.

Around 80% of old panels are landfilled! "Big problem. " One: plastics end up in the environment.

Two: precious metals would just go to waste. And three: recycling saves emissions. So I’m here in the French Alps to find a fix.

"And what this has to do with baking and bathing: now. " We’re at the French company ROSI. Founded in 2017, they’re one of the pioneers in solar recycling.

This is Antoine Chalaux, he has been working here for the past four years. "What are the main process steps in your recycling process? " "So, the first step is to get rid of the polymers.

So, we do it with a thermal treatment. It's a pyrolysis process in a furnace that eliminates the polymers. And then we separate the material with mechanical sortation.

And then you are at the last step because the photovoltaic cells contain different metals. And these metals we want to separate them from each other. So, we have a chemical treatment.

A small light chemical treatment that we do that detaches the silicon from the silver. And this way at the end we recover all the materials inside the PV panels. " Basically, a solar panel is made of a few main ingredients that need to be separated during the recycling process.

You’ve got tempered glass, thermoplastic glue, the cells with silicon, silver and copper, a plastic back sheet and an aluminum frame that holds everything together. Of course, the precise mix of components varies by manufacturer. "Why is it so hard to recycle these panels?

" "So, the good thing with solar panels is that they are made to last very long. 20, 30 years outside in any weather conditions they can last, because of the construction. This construction, with a strong glass sheet in the front with polymers gluing everything together, it's very water-resistant.

The problem is: now we need to recycle them. And we need to separate all these materials to put them back in the economy. And they are all glued together with polymer.

So, the most challenging first step is to separate the materials from the polymers. This is not possible if you crush it, because if you crush it you create small particles all glued together with this polymer. " And the plastic is literally everywhere.

"So, even when you now remove this. You still can't access the cells, right? " "Exactly.

You have different types of polymers, different layers. " "So, there's even more. Oh.

Wow. " "This is difficult, ah? " "Yeah.

" So, the first step is to get rid of the plastics. The panels get put into this big grey furnace. And because ROSI is still in the patenting process, everything today is pretty much top secret.

The mastermind behind this process is Guy Chichignoud – CTO and cofounder of ROSI. "Come with me. " "You can really feel the heat.

You can really feel the heat. Wow! " "How hot does it get in there?

" "400 degrees. " "400 degrees. That's really hot, so we don’t stay too close for long.

" The panels bake for between 1. 5 and six hours, turning the plastics inside into gas. "What is really important when you look at this process?

Does it depend on the temperature? How the panels are stacked up? What makes the difference?

" "What makes the difference and what is our knowledge and IP protection is: of course, it’s not a standard pyrolysis process. It’s customized and optimized for the treatment of solar panels. What we managed to do is to improve the general regulation of the oven depending on the source materials.

So, actually the modules contribute to the process. It’s not an oven with a payload. It’s a combination of the two.

It's coupled. Meaning we use the energy from modules to heat up the oven, so we can save energy. So, it’s a combination — the coupling between the machine, the equipment, the oven and the payload.

So, the combination of the two makes it more efficient. " ROSI sends hazardous gases and exhaust fumes through a five-stage filtering system. They say only CO2 and water vapor are released in the end.

But despite the CO2, recycling still saves emissions compared to mining fresh silicon. Creating the base silicon from quartz, coal and wood chips releases between 8 to 12 tons of CO2 per ton of silicon. ROSI says their recycling process only releases 3 tons.

A reduction of at least 5 tons of CO2 per ton of silicon. The company would not let us show you the solar panels going into the furnace. But this is what the solar panels look like after being "baked in the oven".

This batch is about 20 kilos and represents the content of one solar panel. "You can see the glass. You can see the silicon wafers, which are like super thin.

Yeah. And you can just break them into pieces. Yeah.

And then you've got the copper connectors. . .

" ". . .

copper ribbons. " Now, this mess goes into the next range of machines that take on the sorting job. When you look at a typical solar panel from the weight perspective, it’s about 76% glass, 10% plastic, 8% aluminum, 5% silicon, 1% copper, and 0.

1% silver. And it’s that really valuable silver that’s the main goal of this whole process. Though first, we need to extract the copper and glass.

But… "This whole process isn’t the only way to recycle solar panels. Other companies are trying it with mechanical recycling, for example. It’s less energy-intensive, it costs less and you do not need to deal with chemicals afterwards.

" However, the recovery rates can be lower. Firms like Solar Materials in Germany are using heat, like ROSI, at the start of their process, but no chemical baths. "In Japan, there is even one called the hot blade method.

And like the name suggests: a really hot and sharp knife is used to separate the glass from the rest. " Another German company is — putting it very, very simply — hitting the solar panels with lightning. This bursts them into several components which are then sortable.

"I don't think I can pick a clear favorite right now. " Marius Ian Peters has been researching photovoltaics for more than 20 years and is concerned about how to deal with all the plastics in the solar panels. "I'm not exactly happy, for example, with a thermal process in which the polymers are incinerated, because we would lose those polymers to go into a state for which the elements are still in there.

Now, that being said, it is very hard currently to take a polymer that's inside the solar panel, get it out of the solar panel, and treat it in a way that we can reuse it as a polymer. It's very energy-intensive to do that. And it doesn't really compete both energetically or economically, or ecologically, with making a new polymer.

" So, plastics are going to stay a pain to deal with, but what about the remaining materials after the mechanical sortation? "Now, most of the materials are separated, but we still need to get out the most valuable one that is still in these photovoltaic cells connected to the silicon: it's the silver. " The thousands of pieces of photovoltaic cells in these containers go through a set of five to eight chemical wet baths that are connected to each other.

Here, the silicon and the silver are separated from one another. "It is these tiny tiny silver lines that we are talking about here. Their job in a solar panel is to make the electricity available for direct use or storage in a battery, for example.

" In case you’re wondering, this is as much of the process as we could show you. "Can you specify a bit what kind of chemicals you use? Because chemistry is, like, a really wide term.

" "We avoid the use of organic solvents and strong acids, and we have specific conditions with different baths to treat the photovoltaic cells. " That’s as specific as they would get. Because we can’t really show you the inside of the process, we set it up a small experiment.

So, you first have the photovoltaic cells as they enter and, every step, you can see the silver fingers detach a little more. "It's like really tiny, small fingers. " "Yes, it is very, very thin.

" "Yeah, it almost looks like hair. " "Yeah. " "What's the purity on the silver and on the silicon that comes out of this?

" "So, our processes in general enable [us] to keep the same purity for the material when they come in. So we don't degrade the purity. So, for example for the silver, it comes from silver paste on the cells and silver pastes are, in general, above 90% purity.

For the silicon, it's 99. 99%. " "Okay.

That sounds quite pure. " The recovered purity is in line with scientifically published papers. But for the economics of the process another number is important: how much of the materials is actually recovered.

With their combination of thermal and chemical recycling steps, ROSI says they are able to recover 99% of the glass, aluminum and copper, 90% of the silicon and 95% of the silver. Which means that they get about 10 USD worth of silver out of each solar panel. The other stuff — glass, aluminum, copper and silicon — is worth another 10 bucks.

But of course, the recovered materials cost more than virgin materials. "Do you have the feeling that companies are willing to pay these premiums that you have for recycled material? " "Yeah, unfortunately, they don't pay big premium.

But today all the big companies, all big industrial companies in Europe have very strong targets on CO2 reduction and using recycled material is a very good way for them to reduce their CO2 emission from their raw materials. So, already with silicon, for instance, the CO2 emissions of silicon production is very high. So, for our customers, it's crucial that they use less CO2 intensive materials.

And our silicon completely fulfills this target. I would’ve loved to compare the prices for recovered materials to actual market prices, but ROSI wouldn’t tell me their numbers. Luckily for them, in France there is a so-called gate fee that every solar importer or seller must pay to recycling companies to make sure the panels are rightfully taken care of at their end of life.

Just to put this in perspective: a study by the US National Renewable Energy Lab put the cost of trashing a solar panel at under $5, whereas recycling one would cost $15 to $45. So, how do you make recycling pay? ROSI say they can process around 3,000 tons of solar panels per year here.

Not really that much compared to the millions of tons of trash expected in the upcoming years. And it’s not even enough for them to break even. But they're already planning to build a facility 10 times bigger in Germany by the end of 2025.

Which should be able to handle 30,000 tons per year. However, upscaling such a process is a real challenge, as their CEO told me. "For the very big-scale recycling site, we'll have to organize very well the operators, engineers, technicians, so all the traceability system, and also how to integrate the operators, so human beings with the automation, to reduce the cost to protect to maximum the safety of the site.

" "Also, you can’t use this recycled silicon straight away to form a new PV module. " One of the reasons being: the technology moved on. Twenty, thirty years ago, silicon of 99.

999% purity was used. Sounds pretty pure. However, today silicon more than a thousand times purer is required.

So, you’d need another purification process after this to create new silicon ingots and new wafers to put into new modules. This has been done on the science side. For example, by Germany’s Fraunhofer Institute, a research body that works closely with industry partners.

But ROSI is taking a different route and is selling its recovered materials to the automotive, building and electronics industries. "Another way to make this whole thing easier, and that wouldn’t require engineering the recycling process to perfection, is to redesign these solar panels and make them easier to recycle. " The Netherland Organisation for Applied Scientific Research has developed what they call a "release encapsulant" where a type of trigger is worked into the polymers that make them easier to get rid of during recycling.

Like pressing a button and everything goes poof. "At the National Energy Laboratory in the US, they are taking things up a notch by getting rid of all the plastic. And they are doing this by literally welding glass together.

" That way you wouldn’t need to deal with plastics used for encapsulation at all. But, of course, this is all still happening in the lab. Another promising tech could actually be perovskite solar cells, which I already did a video on.

Because the different layers of perovskite solar panels are created using chemicals, they could also be taken apart easier afterwards by using similar process steps. But they would need to be mass produced, first. "What I can say is that the recycling process for ROSI is working at a pilot facility.

But I’m going to be honest with you: I expected to get to know a lot more details about the process. I don’t even know what chemicals they are using. And the upscaling is going to be difficult as well.

Not just from the process or technical side of things, but they also need to get the financing right. And everything at the same time? Not easy.

Overall, bigger players with a lot deeper pockets will have to get involved to make recycling solar panels at a larger scale a reality. " "If you did enjoy the video: like it, comment on it, share it. And don’t forget to subscribe to our channel.

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