By the close of 2024, global solar generation capacity is expected to reach nearly 2,000 Gigawatts. Solar panels consist of materials like silicon, glass, polymers, aluminum, copper, and other metals that harness solar energy. Typically, a solar panel’s lifespan can extend up to 30 years unless damaged. However, concerns arise over the fate of these materials once solar panels become outdated.
The longevity of solar panels is often cited as around 30 years, but this figure is considered a “best guess,” according to Garvin Heath from the National Renewable Energy Laboratory (NREL). Initial failures in solar panels are more prevalent due to manufacturing or installation issues. Fewer panels fail during their midlife, but failure rates increase as panels approach their third decade. Nevertheless, less than one percent of panels are typically non-operational by this time.
Matt Burnell, founder of ReSolar, a British startup focused on reusing, repowering, and recycling solar panels, has been investigating their functionality. After visiting a solar farm where numerous panels were damaged during installation, Burnell found that most panels still met manufacturer tolerance for reuse and power generation, despite minor imperfections. He noted that, besides manufacturing and installation, weather is the primary factor that diminishes panel functionality, as extreme or aggressive weather can cause degradation.
Panels considered unserviceable after manufacturing or installation can often still generate electricity. Many solar panels are decommissioned after 25 to 30 years, regardless of their operational status, due to efficiency losses. As efficiency wanes, typically due to the deterioration of laminated layers reducing light capture, solar farms often replace old panels to maintain optimal power generation.
Power grids have a finite number of interconnections with specific power capacities, obliging solar farms to generate maximum permissible electricity consistently. As newer modules become more efficient, it becomes more economical for solar farms to replace older panels.
Burnell noted that although there is potential for solar panel repair, the cost of testing and repairing them generally outweighs the cost of purchasing new panels. This economic imbalance can lead to usable panels being discarded, as seen when panels were reallocated to a Ukrainian hospital instead of being wasted.
Recycling of solar panels remains limited, with only one in ten panels being recycled and the rest often ending up in landfills. As more panels reach the end of their service life, particularly in pioneering solar regions like California, landfills might be overwhelmed. In the U.S., decommissioned solar panels fall under various waste regulations depending on their material composition, especially if they contain hazardous substances.
The Environmental Protection Agency (EPA) is considering rule development to standardize solar panel recycling, but without federal mandates or stringent state laws, recycling remains sparse. Regulations in the UK and Europe under the Waste from Electrical and Electronic Equipment (WEEE) directive mandate recycling responsibilities on suppliers.
Recycling techniques include mechanical processes that shred components, with more sophisticated thermal and chemical methods enabling the recovery of rare metals. Most recycled materials like silicon, silver, and copper often end up being of lower quality due to current processes.
Material diversity in solar panels poses challenges for recyclers, complicating the recycling process. While the recycling industry is at its nascent stage, with advancements anticipated, market practices still favor disposal owing to cost constraints.
Recent innovations at the National Renewable Energy Laboratory indicate a move toward more easily recyclable panels by employing laser welding, eliminating the need for adhesive polymers. These developments suggest a promising direction for future recyclability, although existing panels constructed with older technologies still present a significant challenge.
