Guide for Ensuring Solar Glass Recycling Happens for Your PV Panels
A significant portion of framed silicon-based solar panel waste is glass, approximately 67-76%. Ensuring effective recycling of this glass is not only crucial for minimizing the environmental impact but also for achieving circular economy goals, a big value renewable energy investors are looking for. The recycling of solar glass presents unique challenges, particularly due to the use of antimony compounds in solar glass, which complicates the recycling process. We’ll explore the steps necessary to help you ensure solar glass recycling is happening when you send your panels off to be recovered for their material value. We’ll also address the hurdles, solutions, and regulatory framework that are required to facilitate glass recycling.
What are the challenges of solar glass recycling?
Proper recycling of solar panel glass strengthens the supply chain, reduces carbon emissions, creates recycling and transportation jobs, and contributes to a circular economy. However, recycling this material is not as straightforward as it may seem. Flat sheets of glass are manufactured in two primary forms: float glass and pattern glass. While float glass is most common in solar panels, patterned glass also contains antimony, a compound that improves solar glass efficiency but raises environmental and health concerns on the backend.
Glass containing antimony cannot be easily reintroduced into U.S. recycling systems due to its interaction with other materials during the recycling process, which can lead to unwanted emissions and lower quality. This makes recycling solar glass with antimony both costly and technically challenging. Transporting glass cullets (crushed glass ready for recycling) also presents a logistical challenge, as their low density makes transport costly and inefficient.
What is the regulatory support for solar glass recycling?
Currently, there are no specific federal mandates requiring the recycling of solar panels or their components, including solar glass. There are, however, counties and certain states, like Washington, that require all panels must be recycled once they reach end-of-life. Federal laws cover panels if the panels are deemed toxic via the Resource Conservation and Recovery Act (RCRA) and Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). These statutes do apply to how the hazardous waste must be handled.
Future extended producer responsibility (EPR) legislation could require manufacturers to disclose the composition of the solar glass used in their products, including the presence of antimony compounds. By doing so, recyclers would be able to determine whether the glass can be processed and in what types of glass facilities or whether specialized processes are needed for antimony-containing glass. Why is this important? Composition disclosure could transform how the solar recycling industry functions in the U.S., laying the foundation for more effective recycling and ensuring that materials are repurposed safely, sustainably, and economically.
The U.S. could also implement a threshold for antimony levels in solar glass, gradually reducing the allowable amount over time. This would encourage manufacturers to phase out the use of antimony in their production processes and facilitate more straightforward recycling in U.S. facilities. Mandating that solar glass compositions be registered in a centralized database would provide recyclers with the necessary information to handle the material appropriately.
Another critical regulatory step involves the development of a rapid analysis method to detect antimony in solar glass. Current methods are time-consuming and expensive, limiting their practicality for large-scale recycling. A faster, more cost-effective method would allow recyclers to sort solar glass by composition, ensuring that antimony-free glass can be efficiently recycled and that antimony-containing glass is directed to facilities equipped to handle it.
Industry cooperation and innovation are important in ensuring the success of solar glass recycling
While regulations play a crucial role, industry cooperation is equally important in ensuring the success of solar glass recycling. Manufacturers could work closely with recyclers to establish closed-loop recycling systems, where solar glass is recycled back into new PV modules or other high-value products. This requires manufacturers to be transparent about the materials used in their products and commit to sustainable production practices.
Innovation in recycling technology is also essential. Research into new methods for handling antimony-containing glass, such as developing alternative refining agents or improving the efficiency of recycling processes, will be key to overcoming the current recycling challenges. Efforts to reduce the transportation costs of glass cullets, such as establishing recycling facilities closer to recycling and manufacturing sites, can improve the economic viability of solar glass recycling.
How to ensure your solar module glass is being recycled
Ensuring that solar glass recycling becomes a standard practice requires a combination of regulatory support, industry collaboration, due diligence, and technological innovation. By mandating transparency in solar glass composition and setting clear thresholds for harmful compounds like antimony, the U.S. can create a more sustainable recycling system for PV modules. Industry stakeholders must also take responsibility for developing closed-loop recycling processes and investing in new technologies to handle the challenges posed by patterned, antimony-containing glass. With the right measures in place, solar glass recycling can contribute to the circular economy and domestic manufacturing.
Checklist for Ensuring Solar Glass Recycling
To help Developers, EPCs, and Utilities determine whether their solar glass is being properly recycled, the following checklist can be used:
1. Verify the Recycling Facility
✔ Confirm whether the recycling facility accepts solar glass and has the capacity to handle antimony-containing glass, if applicable.
✔ Ensure the facility is located within a reasonable distance from the glass manufacturing site to minimize transportation emissions.
2. Assess Compliance with Regulations
✔ Check if the recycling process follows the relevant hazardous waste regulations.
✔ Ensure the recycler is following best practices for sorting and processing solar glass.
3. Track Recycled Materials
✔ Request documentation that confirms the solar glass was recycled and how it will be reused (e.g., in new PV modules or other glass products).
✔ Confirm that the recycled glass is being reintroduced into the supply chain.
Resources
https://www.nrel.gov/docs/fy21osti/74124.pdf
https://seia.org/news/national-pv-recycling-program-aims-discontinuing-disposal-panels-landfills
https://www.sciencedirect.com/science/article/pii/S0022309323004143