California has seen rapid growth in the use of solar photovoltaic (PV) panels to generate electricity for homes, businesses, schools, farms, utilities, and more. Solar energy is a critical part of California’s efforts to cut air pollution, reduce the use of fossil fuels, and stop the worst impacts of climate change.
In 2002, California passed the nation’s first renewable portfolio standard, mandating electric utilities invest in solar and wind power. A few years later, in 2006, California launched the Million Solar Roofs Initiative to incentivize consumers and businesses to invest in solar energy. Consequently, as of 2021, 20 percent of California’s electricity came from instate solar. Approximately 65% of the state’s solar PV market is found in the utility-scale sector, typically large industrial-scale power plants in the desert regions, while 35% is located on rooftops or on ground-mounted systems at schools, parking lots, and farms.
With a typical 25-year lifespan for most solar PV systems, the majority of solar panels installed in California are still in use today. Like many consumer electronics, solar PV panels can be reused or, once they reach the end of their useful life, they can be recycled. However, reuse and recycling practices need to be supported and promoted. Industry, consumers, and the government can work together to reduce the number of solar PV panels that unnecessarily end up in landfills by increasing reuse and recycling opportunities and practices. Understanding the facts is an important part of building a sustainable energy system.
What is a solar PV panel made of?
There are two types of solar PV panels commonly used today. The most popular, making up 95% of the global market, are crystalline silicon (c-Si). These solar panels are commonly installed on homes or as ground-mounted systems. The panels are rectangular-shaped, and made of an aluminum frame with a glass top and a light polymer backside. Solar panels also have a junction box, which is a small box containing electrical wires on the underside of a panel. Approximately 80% of the solar panel is made of these recyclable materials, which can be recycled relatively easily. The rest of the panel, chiefly the solar photovoltaic cells made of silica (which comes from sand), can be recycled with available specialized machinery. In total, over 95% of a crystalline silicon panel can be recycled.
The other kind of solar PV panels is called thin film, making up approximately 5% of the global market. Many utility-scale solar power plants, as well as some distributed systems such as solar shingles, use thin film. Thin film can be made of thin glass, plastic sheeting, or metal with the photovoltaic material deposited on top in one or more layers. Thin film systems can also be recycled.
Do solar panels contain selenium and cadmium?
The answer to this question is primarily no. In fact, it is a common misconception that solar panels contain large amounts of heavy metals of any kind. Crystalline silicon solar panels, making up 95% of the global market, do not contain any amounts of selenium or cadmium. They can contain small amounts of silver, which technically is classified as hazardous, and lead, used in soldering of electrical components, comparable to what is found in household electronics. Some thin film solar panels do contain selenium, cadmium, or other heavy metals. All of these metals are housed as part of the solar panel itself and do not leak out or expose the surrounding environment unless the panels are crushed.
When can solar panels be reused?
Solar panels are typically warrantied for 25 years. Because there are no moving parts to break or wear out, many of the solar systems that were built more than 25 years ago are still in operation today. Solar PV panels do lose some of their efficiency over time, however, motivating some solar users to replace older, but still functioning, panels with newer more efficient panels.
There is a thriving market for second life solar panels made possible by marketplaces like Energy Bin and a number of companies that specialize in decommissioning solar installations and redirecting the used panels to other customers. The original customers are often eager to resell the used panels, pocketing the funds or using them to offset the cost of a newer system, and the new customers are often eager to buy the panels at discounted prices. There are also companies finding innovative ways for second life panels to generate low-cost clean electricity for power industrial processes that otherwise would have used fossil fuels.
Solar panels that are not broken or defective also are donated to nonprofits such as Habitat for Humanity.
When are solar panels retired?
Solar panels are retired if they are broken or no longer work due to disasters, such as fire or hailstorms, old age, or damage during shipping and installation. Some reduced-efficiency panels are retired instead of reused. In all these cases, solar panels are ideally recycled rather than deposited into a landfill.
Can solar panels go into a landfill?
In California, solar panels can be legally disposed in conventional landfills but only after verifying that the panels do not contain hazardous materials. Designated laboratories commonly provide this verification via testing that can cost upwards of $1,500, which is more than most homeowners are willing to spend. If a solar user does not have the funds to conduct this specialized test and cannot obtain a record of the manufacturing materials another way to verify the absence of hazardous materials, the state of California considers the panels to be hazardous waste by default, triggering complicated rules for disposal and recycling.
How do California regulations limit the ability to recycle solar panels today?
The California Department of Toxic Substances Control (DTSC) classifies solar panels that have not undergone the verification process for hazardous materials discussed above as universal waste, which is a type of hazardous waste. A common form of universal waste is pesticides, which are well known to be toxic and can be more difficult to handle than solar panels. Because solar panels are listed as universal waste by default, recyclers are prohibited from using basic techniques that use heat, chemicals, or water in their recycling processes. Additionally, the procedure to permit a recycling plant is difficult in California. As a result, recyclers that serve the California market often set up facilities in neighboring states. As of July 2022, California had one recycling plant accepting solar panels.
Because solar panels are classified as universal waste, anyone who wishes to bring the panels to a recycling facility must follow strict and costly notification, transportation, storage, training, reporting, and recordkeeping requirements.
While the DTSC’s justification for the austere recycling and handling regulations is that some solar panels contain toxic substances, as discussed above, many panels do not have any toxic substances and those that do have small amounts comparable to household electronics, such as flat screen TVs. Household electronics are classified by DTSC as e-waste. E-waste rules are less restrictive than universal waste which, in turn, promotes recycling and responsible disposal practices. Most cities and counties offer easy-to-use e-waste disposal services for homes and businesses. These opportunities do not exist for solar panels, today, which runs counter to state recycling goals.