Could Europe’s next silver mine already be sitting on our rooftops? A new recycling technology could turn old solar panels into a valuable source of silver and silicon.
Solar panels are designed to withstand decades of heat, moisture and mechanical stress. That durability is valuable during use, but creates a problem at the end of their life.
The glass and silicon cells are bonded tightly together by layers of encapsulant. Silver is used in the conductive contacts on the cells. Panels are therefore often shredded or heated to break down the bonding materials.
Both approaches can make it difficult to recover silver and high-purity silicon without damaging or contaminating them.
TNO has developed a different approach.
A laser weakens the adhesion between the encapsulant and the silicon cells. The different layers can then be separated more precisely, without exposing the entire panel to extreme heat.
According to TNO, the laser-assisted process uses less than 1 kWh per module, compared with around 25 kWh per module for pyrolysis.
TNO expects the process to recover 99% of the silver, while preserving high-purity silicon for reuse in applications such as batteries or new solar cells.
That could become increasingly important as significant volumes of solar panels reach the end of their lifespan in Europe.
It also creates new opportunities for innovation. Valuable technology can lie in the laser treatment, process settings, material separation and integration into an industrial recycling line.
A solar panel is designed to last at least 25 years.
The strategic value of its materials can last much longer.
