Laser Delamination Recovers 99% of Solar Panel Silver at 84% Less Energy

A laser-based recycling process developed at the University of Glasgow recovers silver from end-of-life solar panels with more than 99% selectivity while cutting recycling energy use by an estimated 84% — and its commercialization partner says scale-up could take less than a year.

The technique, described in the journal Communications Materials, targets the scrap stream everyone in the sector is watching: global solar capacity has reached 3 terawatts, and end-of-life panels are projected to generate more than a million tons of waste by 2030, rising past 200 million tons by 2050.

Why the encapsulant is the bottleneck

The economics of solar recycling hinge on a thin slice of mass. Valuable metals make up just 0.05% of a panel's weight but represent two-thirds of its scrap value. They're locked in place by ethylene-vinyl acetate (EVA), a polymer engineered to seal cells for two decades or more outdoors.

Cracking that seal conventionally means heating to 450–600 °C or soaking panels in toxic chemicals — then leaching silver with hazardous, polluting nitric acid. That energy and chemistry bill is what has kept high-value recovery marginal.

How the laser process works

The Glasgow team, working with cell stacks supplied by the Fraunhofer Centre for Silicon Photovoltaics in Germany, used a standard 1064 nm fiber laser to scan decommissioned cells. The light passes almost straight through the transparent EVA and is absorbed by the silicon beneath, heating the interface between the two.

Above a power threshold, the EVA releases as an intact film. Metallic busbars are physically separated, leaving a powder of predominantly silicon, aluminum and silver. The downstream chemistry is deliberately mild:

• Dilute sodium hydroxide removes the aluminum.
• An iron chloride and choline chloride brine dissolves the silver.
• Silver was recovered at better than 99% selectivity in one panel type.

No nitric acid anywhere in the flowsheet — which changes the permitting and handling picture for any operator considering the route.

What the partners are saying

Dr Joseph Cameron of the James Watt School of Engineering, who led much of the work, said: "The plastic that seals solar cells is designed to survive decades outdoors. It is very good at this, but this is exactly why old panels are so hard to recycle. By using a laser, we can release the encapsulant in one piece rather than burning or dissolving it. That gives us much cleaner material to work with at recycling centers. The silver can be pulled out selectively with mild, simple chemistry, and the silicon is left behind ready for recovery."

The paper's first author is Bashayer Alsulami, a recent PhD graduate of the James Watt School, building on her earlier research into metal recovery from end-of-life panels. Professor Jeff Kettle, REACT's principal investigator and corresponding author, noted the project shows what the centre exists to do: "We've taken a global problem and developed a process that a Glasgow laser company can help take towards commercial equipment."

The commercialization path — and its catch

Glasgow-based Watt Laser Ltd is now working with the university to explore taking the technique to market. Declan Brannagan of Watt Laser framed the opportunity squarely: "Solar recycling is about to become a very large market, and the industry needs processes that are clean, selective and economic. What stands out about this work is that it uses standard industrial fiber lasers, the same kind of systems already used on production lines for marking and cutting."

The equipment angle matters for practitioners: there's no exotic laser supply chain to build. Brannagan said scaling from a single laser head to multi-head systems handling full panels at commercial rates is an engineering challenge his company understands well. His timeline and his condition were equally direct: "We expect that scale-up of this technology will take less than a year, but needs an industrial end player to firm up throughput at this stage."

The research sits within the EU APOLLO project and REACT — the Responsible Electronics and Circular Technologies Centre, led by the University of Glasgow and backed by UKRI. Researchers from Princess Nourah bint Abdulrahman University in Saudi Arabia and the Fraunhofer Centre for Silicon Photovoltaics co-authored the paper.

What happens next depends on one thing: whether an industrial recycler signs on to anchor throughput. Until that end player appears, this stays a demonstrated lab process with a claimed sub-year path to equipment — watch for the first pilot-line announcement.