Solar panel waste can include heavy metals such as silver, lead, arsenic and cadmium, which, at certain levels, can be classified as hazardous waste. According to Dr. David H. Nguyen, an oncological biologist, toxic chemicals in solar panels include cadmium telluride, copper and indium selenide, cadmium and gallium (di), copper, indium and gallium (di) selenide, hexafluoroethane, lead and polyvinyl fluoride.
Silicon tetrachloride, a by-product of crystalline silicon production, is also highly toxic. Because of the variation in design and components, tests have shown that some solar panels can overcome TCLP while others fail. In a nod to environmental concerns, many owners of used solar panels already recycle them instead of throwing them in landfills and thus derive residual value from their old equipment that would otherwise be thrown away. States, including Washington, where the Photovoltaic Module Management and Return Program will require solar panel manufacturers to finance recycling at the end of their useful life.
Government subsidies are one way to make solar panel recycling economically viable for waste generators, who now assume much of the cost of recycling. A summary of the hazards of cadmium compounds prepared by the EPA points out that exposure to cadmium can cause serious lung irritation and lasting impairment of lung function. Manufacturers of solar panels usually guarantee that they retain 80% of their efficiency for about 20 years. For any user of solar panels, this is not an immediate risk, since it only affects manufacturers and recyclers.
These solar panels usually contain small amounts of valuable metals embedded inside the panel, such as silver and copper. California has been a pioneer in boosting rooftop solar energy, and has created the largest solar market in the United States. Thin-film solar cells contain thin layers of semiconductive material, such as cadmium telluride (CdTe) or copper, indium and gallium diselenide (CIGS), which are superimposed on a support material such as glass, plastic or metal. By 2030, the United States is expected to have up to one million total tons of solar panel waste.
Solar panels provide clean, renewable energy from the sun, and their prevalence as an energy source has been increasing. The department expects that the number of solar panels installed in the next decade will exceed hundreds of millions in California alone, and that recycling will become even more crucial as cheaper panels with a shorter lifespan become more popular. Crystalline silicon solar panels are efficient, low-cost and have a long lifespan, and the modules are expected to last 25 years or more. Whether it's thousands of non-recyclable wind turbine blades reaching landfills or the growing recognition that solar panels contain toxic heavy metals that can pose a risk to the environment if leaked through the panels, the environmental costs of “renewable energy” are becoming more evident every day.
The board of directors surveyed local residential solar energy owners and found that many, not knowing what to do with the panels at the end of their useful life, were asking installers for help.