Venice-based startup 9Tech has developed a highly efficient method for recycling solar panels, enabling the recovery of up to 99% of components. This innovative approach is significantly cleaner and greener than conventional recycling methods, as it avoids the release of toxic fumes.

As the global push for cleaner energy sources intensifies, it is estimated that 400 gigawatts of solar power are being added to the grid annually, a figure expected to more than quadruple by the decade’s end. While this growth is positive, environmentalists are concerned about the waste generated when solar panels reach the end of their lifespan. Built to withstand weather events for over 30 years, solar panels are tough and challenging to dismantle, making recycling or component recovery particularly difficult and reliant on harsh chemicals.

Challenges of Solar Panel Recycling

Most of today’s solar panels are of the crystalline silicon type, composed of silicon wafers coated with silicon nitride. Conductors made from silver and copper are printed onto the wafer surface, and the entire assembly is laminated in adhesive polymers for moisture protection. This setup is further encased in tempered glass and an aluminum frame. The primary challenge in recycling is the sticky polymer adhesive, which can be burned off, releasing harmful gases. Recovering expensive components like silver involves using toxic reagents such as hydrofluoric acid and nitric acid, making landfills a more convenient but environmentally harmful option.

9Tech’s Eco-Friendly Recycling Method

9Tech has introduced a revolutionary recycling method at its pilot plant in Venice. Here’s how the process works:

  1. Initial Disassembly: The aluminum frame and tempered glass are removed, leaving a sandwich of silicon wafers, metal conductors, and sticky polymer.
  2. Combustion Furnace: The components are heated to over 750°F (400°C), vaporizing the polymer. A filter captures the fumes’ content, and the furnace heat is repurposed.
  3. Material Separation: The remaining materials are passed through sieves and rollers to separate the silicon based on thickness and mechanically strip out the copper.
  4. Silver Recovery: An organic acid, aided by ultrasound, is used to separate the silver from the silicon pieces. A mesh net removes the silicon pieces, leaving silver in the solution, which is then filtered or centrifuged.

This process allows 9Tech to recover 90% of the silver, 95% of the silicon, and 99% of the copper from the solar panels. Although more expensive than traditional methods, the high purity and value of the recovered materials can offset the costs. The purity of the materials also makes them suitable for reuse.

Future Plans

9Tech aims to build a demonstration facility capable of processing 800 panels daily. This facility will not only help in recycling solar panels but also fine-tune the economic viability of operating a large-scale recycling plant.

With this innovative approach, 9Tech is set to make a significant impact on solar panel recycling, contributing to environmental sustainability and the efficient reuse of valuable materials.

By Impact Lab