Solar energy is catching on and becoming more affordable to families. Homes in states across the nation are putting solar panels on their rooftops and on stands in their yards. Recycling those solar panels is new as the first solar panels being put on homes are now reaching their end-of-life. That leads to a problem. It’s time to consider some of these issues with solar panels and decide the best ways to recycle solar panels when they reach their end-of-life.
State Regulations May Make It Okay to Trash Them, But That’s Not Ideal
It’s estimated that most photovoltaic solar panels will last 30 years. Some do last longer, but the majority make it to the 30-year mark. Panels that were installed in the 1990s are reaching the point where they need to be decommissioned and recycled. The U.S. hasn’t set forth specific policies on recycling. Some states are doing this on their own. Washington was the first state to put a solar panel recycling mandate in place.
California and New York are also looking into recycling policies for solar panels. In 2015, California passed SB 489, which requires solar panels to be treated as hazardous waste and disposed of as such. The goals are to design PV modules for extended life and to repair and reuse them when possible.
The International Renewable Energy Agency (IRENA) teamed with the International Energy Agency Photovoltaic Power Systems Programme (IEA-PVPS) to assess what would happen when solar panels reach their end-of-life and become a prevalent new form of waste. They found that 90% of the materials are recyclable, so there’s an urgency to get recycling plans in place. If those materials were recycled, it could release more than 75 million tons of raw materials back into the manufacturing stream by 2050.
Multiple Materials Go Into Solar Panel Construction
There are three main types of solar panels: monocrystalline, polycrystalline, and thin-film panels. Each one is made in a slightly different manner, which can change how they are recycled. No matter which panel you’re recycling, there’s going to be glass, plastic, and metal.
To look at how solar panels are broken down, it helps to know how they’re made. It all starts with sand. Solar panels contain silicon, which is abundant in beach sand. That sand is collected for the silicon, which is then heated to extremely hot temperatures to get the silicon.
The silicon is melted together and boron is added to ensure the silicon has positive electrical polarity. That’s important to solar energy production. The mix of silicon and boron is shaped into cylindrical ingots. Monocrystalline cells are made from one crystal of silicon. Polycrystalline cells require multiple crystals of silicon.
Once the ingots are set, they’re sliced into discs or wafers using a wire saw. Those wafers are paper-thin, but they’re shiny and reflective. To make sure the sun’s rays aren’t reflected from the solar panel, the wafers are coated with anti-reflective materials.
After the anti-reflective coating has adhered, the wafers are treated with metal conductors. That coating also helps soak up the sunlight. Phosphorus is added as a final coating to create the negative electrical charge that makes the photovoltaic cell work properly.
Each of those wafers is connected to create the full solar panel. You can have up to 72 cells per panel, depending on where they’re being installed. The cells are covered by a glass panel on the side that faces up and a polymer on the bottom to create a waterproof, airtight panel that water and dirt cannot get into. A final metal frame is affixed to the sides to secure everything. This metal frame is secured using ethylene vinyl acetate (EVA) adhesive.
You also have thin-film solar panels. They differ from silicon solar panels as they’re narrow and use solar cells that are made from amorphous silicon, cadmium telluride, copper indium gallium selenide, or gallium arsenide. Some of these materials are carcinogens and must be handled correctly and responsibly when being recycled.
Carefully Deconstructing a Solar Panel Assures Materials Can Be Reused
While a lot goes into a solar panel, many of the materials are recyclable. Glass makes up the bulk of the materials that are recycled. Around 90% of the thin-film panels recyclable materials are glass. Almost 80% of a silicon panel is glass. Other recycled materials are:
- Plastic – 10% (silicon) and 4% (thin-film)
- Aluminum – 8% (silicon) and 6% (thin-film)
- Silicon – 5% (silicon)
- Other metals – 1% (Both silicon and thin-film)
Silicon and thin-film solar panels enter into different recycling steps. Take a look at the differences.
#1 – Silicon-Based Panels
The first part of the recycling process involves collecting the panels bringing them to a solar panel recycling facility. There, the aluminum and glass are separated from the photovoltaic cells. Glass is crushed and melted down where much of it can be reused in new glass products. Metals are also melted down and reused.
The coverings that were added to the silicon wafers are heated so that they evaporate. The metal materials added to the wafers are scraped or etched off. Some of the metal from the metal conductors will be reused. After cleaning, the waters are melted down and used in new products.
#2 – Thin-Film Panels
Like the silicon-based panels, they’re trucked to a facility that can recycle them. The laminated panels are fed into shredders to break them down into pieces that are usually no larger than 6 millimeters. They go into a screw pump where the solids and liquids are separated as the laminated film is removed through a mixture of chemicals. They’re rinsed and vibration is used to separate the layers.
Metals end up on one conveyor to get melted down and reused. Glass undergoes a final rinse and is melted down for reuse.
Other Components in the Solar Array Must Be Recycled, Too
That’s the solar panels. What about the rest of the solar array? To get the energy from a solar panel to the power lines, additional equipment like junction boxes and the solar panel inverter that turns the solar power from DC to AC. That solar panel inverter is a metal and plastic box that’s usually mounted in the basement or mudroom of a home. Power cables connecting the solar panels to a power meter and the solar panel inverter are also part of a system.
When you’re recycling solar panels, you may be recycling more than the panel. You might also have to recycle these electrical and computerized components. That’s going to require a specialist in electronics recycling.
Choose the Best Solar Panel Recycling Partner
Ask the solar panel manufacturer if there are any incentive programs. They may have tips on where to turn for help with solar panel recycling. Solar Energy Industries Association has its own list of tips for PV end-of-life management. One of the agency’s biggest tips is to choose an e-waste recycler that holds e-Stewards and R2 certifications. ERI does hold both e-Stewards, R2, and several other certifications that assure you nothing is going overseas or being improperly recycled.
ERI is the nation’s leader in electronics recycling. If you need an expert to properly recycle solar panels, inverters, metal hangers and frames, nuts and bolts, and the power cables, we can help. Call us to ask about recycling every part of a solar system.