Dubbed the “sunrush,” the growth in solar energy use over the past 25 years has been exponential. In addition to increasing global capacity from 100 MW to over 300 GW in that time, costs in 2017 were an impressive 86% lower than in 2009.
One emerging concern, however, results from the fact that the life cycle of a typical solar panel is about 25 years. The glass and metal material from retired photovoltaic (PV) panels will begin to add up to millions of metric tons, and current recycling infrastructure may not be sufficient for dealing with such a large quantity of these materials.
Perhaps unsurprisingly, the process of recycling solar panels is fairly complicated, involving heat systems that burn up the adhesives as well as other methods used to separate out the crystalline silicon and the precious metals in the panels. The wide variety of materials used—from glass, aluminum, and synthetic sealing materials to metals like lead, copper, and gallium—makes it difficult to efficiently process and recycle them. Mark Robards, director of special projects for ECS Refining, says, “Nearly 75% of the material that gets separated out is glass, which is easy to recycle into new products but also has a very low resale value” (quoted on the website Ensia.com). If they aren’t recycled, PV panels cannot be sent to landfills since they are made with heavy metals and other toxic substances that can contaminate the surrounding soil, air, and water.
Along with the current difficulties of recycling solar panels, the changing makeup of the panels themselves presents a challenge. As manufacturers continue to improve their technology, they search for more cost-effective ways to construct panels. These methods often involve using alternative components—like a material called perovskite—rather than more easily recyclable materials like silver and copper. While solar panel costs are dropping and enabling the technology to become more widespread, the need for better recycling infrastructure is growing every year as more and more panels reach the end of their life span.
The solar energy industry in the US may take inspiration from a recycling association in Europe called PV Cycle which has developed a process for PV module recycling that is both environmentally and economically conscious. In 2016, they achieved a 96% recycling rate, a new record for silicon-based solar panel recycling. The head of Treatment & Operations at PV Cycle, Olmina Della Monica, remarks that their success “is the result of both continuous improvement and intensive research and development along the value chain.”
In contrast to the US, Europe’s PV panel disposal management is regulated by the EU’s WEEE (Waste of Electrical and Electronic Equipment) directive. Manufacturers of solar cells must obey legal requirements and specific recycling standards, operating with the mindset that these panels will need to be recycled at the end of their life span. There is no similarly strict control in the US, but California has initiated legislation on solar panel disposal that supports the PV module industry in making end-of-life management of PV modules convenient for both consumers and the public. As the “sunrush” continues, legislation like this will hopefully become ubiquitous across the nation.
What suggestions do you have for future policy development in the solar energy industry?