Solar panel recycling: How does it work?

Solar power is one of the fastest-growing clean energy sources, but what happens to old panels? Solar panels have a lifetime of about 30 years. With the increasing number of solar panels being sold and installed in the U.S. each year, it's only a matter of time before high volumes of panels are at the end of their useful life and have to be disposed of. Solar panel recycling is still at an early stage, but as the renewable energy market continues to expand, recycling processes will play an increasingly important role.

Solar energy is inexpensive, fossil fuel, and emission-free, and boosts sustainability efforts. But, it's important to note that after about 30 years, many crystalline silicon solar panels will start seeing significant dips in energy production. So, it may be time to replace or dispose of them entirely. More and more panels will reach the end of life each year (some experts think we'll have 80 million metric tons of solar panel waste by 2050). Even now, old panels are becoming a problem as most of them end up in landfills where they can release toxins harmful to the environment and human health.

Recycling solar panels is good for the environment

Like any manufactured product, disposing of solar panels is hardly environmentally friendly. Heavy metals in solar cells, like cadmium and lead, can become hazardous waste if not recycled or disposed of properly. Additionally, solar panels that are carelessly thrown away can end up in large landfills (as most of them do currently due to the solar panel recycling process' infancy). By recycling solar panels, we can keep harmful materials out of landfills and the environment.

Recycling solar panels repurpose rare, expensive elements

Besides environmental protection, recycling solar panels will be economically impactful as well. Some rare elements in photovoltaic (PV) cells, like gallium and indium, are being depleted from the environment over time. If we could recover these valuable materials, we can conserve the limited amount available on earth and continue to use them for photovoltaic panels and other products. Furthermore, a 2016 study by the International Renewable Energy Agency (IRENA) estimated that $15 billion could be recovered from recycling solar modules by the year 2050. By recycling solar panels, we can conserve essential materials that can go back into new panel products, alleviating supply chain constraints and ultimately lowering the cost of solar.

Solar panels are made from several components, including:

• Silicon solar cells

• Metal framing

• Glass sheets

• Wires

• Plexiglas

Right away, it's clear that many of the core components of PV panels can be recycled on their own. Metal, glass, and copper wiring can all be recycled and reused. Silicon cells, the component most essential to producing electricity, are a slightly different story. While silicon wafers are not recyclable like glass and plastic, some specialty recycling companies can reuse silicon cells by melting them down and reclaiming the silicon and various metals within.

Technically, all solar panel parts are recyclable materials with the correct process.

There are three main ways to recycle solar panels: re-use, mechanical recycling, and chemical recycling. Each of these methods has its advantages and disadvantages, and all likely will still have a place in the solar recycling industry as it grows.

Re-using or refurbishing solar panels

Throughout this article, we're referring to "recycling" as breaking down solar panels into their component materials and then using those recovered materials elsewhere, including in other solar products. However, there's also the concept of "re-using" solar panels, which is a different solution for the solar waste problem.

Re-use is an enticing recycling method for PV modules because of how little processing products require. However, solar panels past their warrantied life cycle usually produce significantly less energy than when they were new, rendering them highly unusable for solar power generation. There's still a place for used solar panels, but it's not a long-term or permanent solution for the coming solar panel waste problem.

Re-using solar panels makes sense for small off-grid applications, where producing electricity super efficiently with the latest solar technology isn't essential. It's also applicable for small, specific solar chargers, like keeping electronic signs on the highway powered or charging an e-bike station. Otherwise, used or refurbished panels don't produce enough electricity to be useful as parts of larger solar arrays.

Mechanical recycling

One of the two proper "recycling" methods for solar panels, mechanical recycling, is the recycling process that involves physically breaking down solar panels into their components. On the rudimentary end, an automated recycling process might remove the aluminum framing from a panel. Then, the remaining glass, silicon, wiring, and various metals are ground into a mixture known as "glass cullet." Glass cullet is sometimes used as a building material.

Some companies use mechanical methods to get more out of panels than just the aluminum frame. It takes more time and precision, but we can use machines to physically separate the smaller parts of solar panels, such as the intra-cell wiring and silicon itself.

Chemical/thermal recycling

Perhaps the most exciting segment of solar recycling is chemical (or thermal) recycling. While mechanical recycling is limited by how well a process can physically separate different components, chemical recycling uses reactions at a molecular level to separate the ingredients in a solar panel. For example, the company ROSI Solar, a French startup, uses a chemical process to extract the tiny silver wires that carry electricity through silicon cells in a working solar panel.

Solar panel recycling is still in its infancy; however, across the ocean in Europe, it is a much more established part of the solar industry.

The key difference between U.S. and European solar recycling is the lack of policy guardrails in the states. In Europe, solar panel manufacturers must handle the recycling of their panels once they've reached the end of their usable lifespan. In the U.S., no such federal regulations exist. However, some states have enacted laws to regulate solar end-of-life management for solar panels. California, for example, has Universal Waste Management Regulations. We still see low panel recycling rates in U.S. solar recycling due to higher costs, technical complexity, and lack of policy around solar panel disposal.

So, who in the U.S. is working on solar recycling? In place of manufacturers being required to handle their product recycling, several private companies are working on their practices and technologies. Here are a few to be aware of:

EnergyBin

EnergyBin connects businesses within the solar industry to provide solutions for the repair, resale, and recycling of solar panels. Effectively acting as the "middle man," EnergyBin aims to facilitate quick and easy exchanges in the "secondary market" across the solar supply chain.

We Recycle Solar

We Recycle Solar works directly with manufacturers and installers to properly dispose of their solar panel waste. They have two processing plants in the U.S. in New York and Arizona, alongside several other international locations. Process-wise, We Recycle Solar uses mechanical and chemical methods to extract as many raw resources from their panels as possible.

Veolia

Unlike the U.S., Europe has a developed solar market. Due to government regulations, European solar panel owners must recycle their panels once they are done using them. This has created a demand for panel recyclers, one of which is Veolia.

Veolia partners with the European nonprofit PV Cycle to collect and recycle solar panels. They opened their first recycling plant in 2018, where robots separate glass, silicon, plastics, and metals from solar panels.

Solar panel recycling may not be widespread yet, but solar energy is still an environmentally friendly financial investment. You can cut your electric bill by going solar. Sign up for the EnergySage Marketplace to receive free quotes from our network of qualified, pre-vetted installers so you can start going solar.