According to the Solar Energy Industries Association, “Solar energy is the cleanest and most abundant renewable energy source available, and the U.S. has some of the richest solar resources in the world.”(1) With a lifespan ranging from twenty-five to possibly one hundred years or more, photovoltaic (PV) panels are efficient, effective composed of natural materials such as glass, aluminum, copper, silicon and lead.
How much lead is in a solar panel?
Lead is used in the solder to interconnect photovoltaic cells as part of the manufacturing process. The typical silicon solar panel (which constitutes over 95% of all installations (2) contains approximately 12-14 grams of lead. (3)(4) Note, newer generation PV panels are switching to lead-free solder in their manufacturing. (4)
For a solar panel weighing 40 pounds, the lead concentration is 175 parts per million (ppm). This concentration percentage remains constant regardless of the number of panels: whether it is two, twenty or two hundred panels, the lead content, based on total panel weight, remains the same: 175 ppm.
How do solar panel lead levels compare to USEPA lead levels (limits) for soil and water?
The lead content in solar panels is significantly lower than USEPA standards for soil:
- The USEPA standard for lead in bare soils on play areas is 400 ppm, more than double the lead levels found in PV panels. (5)
- The USEPA standard for lead in bare soils on non-play areas is 1200 ppm, almost seven times the 175 ppm found in solar panels. (5)
Thus, apart from the physical harm of sharp edges from crushed panels, using crushed panels in play or non-play areas, in terms of lead levels, would be permissible under USEPA standards. When used as an aggregate material in bituminous asphalt for roads, walls or other construction, crushed solar panel glass would have easily acceptable lead standards per EPA requirements.
However, waste panels cannot be disposed of near places that would affect drinking water as the United States drinking water standard for lead is 15 parts per billion (ppb). (5)
Are there universal waste standards for solar panels?
Recognizing the fact that solar panels can be recycled without environmental harm has led states to begin classifying them as Universal Waste. (6)
Currently, California and Hawaii classify solar panels as universal waste (rather than hazardous due to the lead content) and consideration for universal waste classifications are underway in New York and North Carolina. (7)
At the federal level, EPA is in the process of creating a formal proposed rule, scheduled to be released in 2025, that reclassifies solar panels as universal waste. This reclassification should recognize the actual low lead content of photovoltaics to improve the management of end-of-life solar panels, i.e., promote recycling.
Conclusion
When it comes to lead, recycling solar panels instead of filling landfills is a wise choice and protects the environment. As long as the recycled product does not come into contact with drinking water, using solar panel glass aggregate is a useful and non-toxic alternative due to the already low lead levels. Assuming that the crushed glass panels are a percentage of an aggregate mix, the 12-14 grams of lead from a 40-pound panels would be further diluted, reducing total lead content.
- https://www.seia.org/initiatives/about-solar-energy
- https://www.epa.gov/hw/end-life-solar-panels-regulations-and-management
- “Recent Facts About Photovoltaics in Germany” Fraunhofer Institute for Solar Energy Systems, section 20.1
- https://www.pv-magazine.com/2019/10/26/the-weekend-read-a-lead-free-future-for-solar-pv/
- USEPA Region III, “Lead in Soil”, August 2020
- https://www.bdlaw.com/content/uploads/2023/12/Law360-Expanding-EPAs-Universal-Waste-Rule-For-Renewable-Energy.pdf
- https://www.esglegalsolutions.com/2023/11/solar-panels-may-be-hazardous-waste-no-more/