While transitioning from silver to base metals like copper in solar panels presents manufacturers with significant advantages in cost and availability, new research suggests it could potentially decrease the future economic viability of recycling end-of-life PV modules.
Researchers from the University of New South Wales (UNSW), Poland’s Gdansk University of Technology and the Polish Academy of Sciences, have analyzed the material composition of diverse solar panels in the Australian market as part of efforts to better understand the profitability of recycling processes for the growing PV waste stream in Australia and similar markets.
“There is still a lack of comprehensive, experimentally derived data on the material composition of diverse photovoltaic panels in the Australian market,” the researchers said. “This paper addresses this gap by providing a detailed characterisation analysis of 12 different PV panels from various manufacturers.”
The study shows that despite variability in material composition across the different panels, the key components – including aluminium, glass, ethylene and vinyl acetate (EVA) laminate, and solar cells – are all recyclable and meet raw material production requirements.
The researchers said the study also reveals potential barriers for future recycling with the variability between panels produced by different manufacturers posing a threat to effective commercial recycling processes.
Among the issues highlighted is the significant variance in solar cell composition with a reduction of silver content in newer panels. The copper content also varied depending on the cell technology of the panel.
“A consistent year-on-year decline in silver content was observed in solar panels, signalling potential decreases in economic revenue for recyclers,” the researchers said, adding that “this trend warns recyclers of potential decreases in future economic revenue, as silver comprises up to 47% of a panel’s recoverable value.”
The study also shows that the recyclability of each of the components depends heavily on the composition with both aluminium and glass being reduced in value as a result of contamination with various impurities.
The research team said that while the glass can be recycled, there was obvious variability among the samples with the potential to significantly decrease the recyclability.
“As a result, the only option for recycling the glass in these cases may be downcycling the glass into concrete, aggregates and road base materials …severely diminishing the value of the glass,” they said.
The findings show that up to 98.3% of aluminium frames are suitable for recycling but warned that surface coatings containing high amounts of sulphur decrease purity and economic value.
The researchers said the findings of the study could be used to inform policy development, optimise recycling strategies, and better forecast the economic viability of recycling processes for the growing PV waste stream in Australia and similar markets.
Management of end-of-life solar modules is a significant issue in Australia with an estimated 4 million panels being decommissioned each year. Government analysis shows only 17% of those panels are currently being recycled and forecasts that the waste stream will increase to more than 90,000 tonnes annually by 2030, and a cumulative 1 million tonnes by 2035.
The study “Beyond assumptions: Experimental characterization of end-of-life photovoltaic panels composition for recycling in Australia” was published in Solar Energy Materials and Solar Cells.
