One of the most exciting developments in the solar sector in the past decade has arguably been the build-out of solar panel recycling plants around the nation. Solar panel recycling, formerly only an issue for further down the line, is now occurring at scale by firms fully engaged in the specialized sector – We Recycle Solar, SolarCycle, SolarPanelRecycling.com (SPR), and many more.
Of course, recyclers are part of a green-minded sector, but they don’t handle solar panels solely for the warm fuzzies. They are operating a company after all. The aluminum frames and recovered copper, silicon, and silver are the biggest moneymakers from recycled silicon solar panels today.
At the end of the day, for recycling to work, somebody needs to consume the goods you’re making, and that has to happen at scale, said Brett Henderson, CEO of SPR.
“When you break a silicon panel down into all its base commodities to be recirculated back into manufacturing industries, most of any panel is glass. Glass is not a particularly precious commodity.”
“And you’re getting to subsidize it by collecting aluminum, silver,”
said Peter Gallo, a researcher at the University of California, Los Angeles.
Like recyclers, manufacturers play the commodities market. Silver costs are soaring; therefore, some panel makers are looking at versions that utilize less of the valuable metal. Panels without silver would cost less to make, but they’d also be worth less when recycled. Such manufacturing developments are pushing recyclers to become some of the market’s most informed solar panel specialists.
The recycling methods discussed here focus on the primary option in the global solar industry: silicon solar panels. First Solar’s local manufacturing base has resulted in several utility-scale solar projects in the United States using cadmium-telluride (CdTe) thin-film panels. However, its design is not as appealing to third-party recyclers. Cadmium and tellurium are not in demand in the market today. Thin-film panels are aluminum-free (no frame).
The first step in recycling silicon solar panels is to take out the junction boxes and frames. What’s left is mostly that inconsequential glass. But the more thoroughly and skilfully you remove that glass, the simpler it is to get to the more precious bits.
Solar panel recyclers spend most of their R&D time removing the glass, whether by grinding it off, using force, or some other means. SPR recently completed a $12 million improvement at its three recycling operations (in North Carolina, Georgia, and Texas), and can now extract glass without nicking the silicon wafers and encapsulants underneath. OnePlanet, a solar panel recycler based outside Jacksonville, Florida, has devised a recycling technique that recovers 99.5% of module glass with 99% glass purity, said CEO André Pujadas. OnePlanet achieves this using high-velocity airflow that splits and fractures the glass apart from the other components.
Once the glass is removed, all recyclers do much the same: they shred the silicon wafer and its connections into a fine powder and run it through density separation, leaving copper and a silver-silicon mix. Recyclers can easily sell copper, whereas refineries can better divide the silver and silicon to sell to bigger buyers.
“Having [refining] in-house is not going to be a competitive advantage. They accomplish this at huge scale for industries all around the globe. SPR is not attempting to re-invent the wheel,”
Henderson said.
However, the recycler could benefit from OnePlanet’s patented recycling method.
“When you remove the cleaner glass, the silver-silicon mixture is less contaminated with crushed glass,”
Pujadas said.
“That means the end product is concentrated into 95 percent pure silicon with 1 percent silver – a more valuable commodity for refineries.”
“The whole business philosophy here would be to extract and recover minerals and re-introduce them into the supply chain for re-consumption, that is, to encourage a circular economy,”
he added.
“A big part of that is how much value you extract from the whole value chain. This recycling method is extremely high-purity silicon-focused. [Eventually] we will have enough silicon that it may be a feedstock for producing metallurgical grade silicon.”
They may also appear sooner than anticipated. Already, panel recyclers are watching future manufacturing trends to see how they may affect their ability to stay in business.
Most silicon solar panels are built to perform well for at least 25 years or more, so we haven’t yet seen a wave of panels retire from the first big wave of U.S. installations in the early 2010s. But enough panels are damaged by shipping and handling, poor weather, and production faults that recyclers must anticipate tomorrow’s trends now.
Henderson said SPR installed bifacial recycling technology at its processing locations within two years of its launch. “We’re putting new technology into our stream immediately,” he stated.
SPR has research analysts on staff to quickly track manufacturing trends and help determine whether the recycler needs a new processing technique or additional offtakers for different material compositions. If solar panels consume less silver, the copper may be worth more, but the silicon-silver combination may be less desirable to certain refineries. Recycling is the simple part; the hard part is finding the proper commodity buyers.
“We’re starting to see technology out there to not use any silver on a solar panel, or much less. If it’s still this silicon-based technology, it’s just going to change the economics of it,”
said Henderson.
“Over time, insurance costs go up, equipment costs go up, labor costs go up, regulatory costs go up. And then if you’re taking one of the components that helps subsidize it out, it’s definitely going to mean that asset owners are going to have this roller coaster on how recycling prices may be.”
Tandem perovskite-silicon panels are still new to the market, but several recyclers are already thinking about how to handle them. Another worry is the use of lead, which would need stronger encapsulants to keep out moisture and be tougher to break to access the important components. And then there’s the lead poisoning issue.
It may be a dangerous substance, and then you have to deal with transportation and full-framework disposal under a hazardous-waste scenario, Pujadas added.
“Then you have to double down on your emission systems and safety culture. That might be done. But when do you start doing it?”
That’s the puzzle in the solar panel recycling space: whether to invest in new processes and when to rely on a constant supply of existing technology. That’s why today’s controllable efforts—such as improving glass removal and silicon purity—will help any solar panel design.
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