Since 2010, the price of photovoltaic panels has dropped by 70%. Coupled with a host of government subsidies, carbon neutrality, the need for home energy storage, renewable energy and more, photovoltaic panels have become an integral part of the public grid as well as many home rooftops. When these photovoltaic panels really come to the end of their lives, what is waiting for them?
1. Photovoltaic panel recycling - not simple
Landfill is the ultimate destination for photovoltaic panels? The recycling of photovoltaic panels is not so simple, because it is a multi-layer device made of different materials, and each layer of materials requires different recycling methods. Easily recyclable materials such as glass panels and aluminum frames make up 80 percent of a typical PV module, according to the Solar Energy Industries Association (SEIA), with the remaining 20 percent depending on the type of panel. Take the silicon-based photovoltaic module, which accounts for 90% of the global market, for example. It is topped with a silver grid of silicon cells. In addition, there is a layer of ethylene-vinyl acetate (EVA) in the middle of the battery.
Finally, at the back of the panel, there is a plastic junction box with some copper wires in it. While these materials are potentially recyclable, separating them out is a labor-intensive and complex process. Ideally for recycling, the PV panels end up in a glass recycling facility with the copper wires stripped. Then, the recycling workers also successfully shredded the glass panels without damaging the photovoltaic panel sandwich components. At this stage, recycling yields a less shiny vitreous powder, also called cullet, which can be used in building materials or other industrial applications.
That compares to $2 to send a silicon cell module to a landfill, so you can see why only about 10% of panels in the US are recycled. What if we could recycle the silicon and silver that make up 60% of the module's value? To do this means high-temperature heat treatment and chemical treatment on top of mechanical recycling, resulting in higher recycling costs. In this regard, some researchers also evaluated the recycling benefits of 2,000 tons of photovoltaic panels and found that recycling silicon may not even be enough to offset the cost. Experts say none of the aforementioned processes will be profitable because silicon-based panels, unlike thin-film modules, lack precious metals such as indium and gallium.
In addition to their inherent low economic value, photovoltaic panels are fragile and may be classified as hazardous waste if they fail the heavy metal leaching test. That said, solar panels also need to be treated to minimize heavy metal leaching, which means recycling requires a professional labor to handle these photovoltaic panels, adding additional costs. Even the cheapest way to recycle, throwing photovoltaic panels into landfills, contains harmful chemicals such as lead and cadmium that have environmental impacts, such as contaminating soil and groundwater. All in all, compared with top 10 power battery recycling companies in China, photovoltaic panel recycling is a thankless task, but with the advent of photovoltaic panel garbage, recycling is a must do.
2. Comparison of photovoltaic panel recycling policy
According to the International Renewable Energy Agency (IEA), by 2050, the United States may have nearly 80 million metric tons of photovoltaic panel waste worth. But so far, only five states in the U.S. have enacted solar panel scrapping policies. Meanwhile, in the U.S., the only law holding producers accountable for solar panel recycling won’t go into effect until 2025, meaning consumers are still paying the price. While the U.S. has not shifted recovery costs and responsibility from users to producers, some changes have been made. California has changed its solar panel waste label from "hazardous" to "generally hazardous" in 2021.
For this new category, the collection, transport and storage requirements for PV modules are lower. Although recycling solar panels is currently an expensive process, it will likely pay off in the long run. There are estimates that the value of recycled solar panel materials could reach $2.7 billion by 2030. Multiply that by a factor of 30 to get the overall market potential in 2050. The main drivers of this crazy growth will come from rising energy costs, technological progress and regulatory push.
In this regard, Europe has done much better than the US, and as early as 2014, they listed photovoltaic panels as e-waste. For example, PV Cycle has developed a recycling program to help manufacturers meet recycling obligations. In February 2020, the EU-funded company partnered with Veolia to recycle nearly 95 percent of its PV panel modules in France, well above the mandated requirement. Veolia also launched Europe's first solar panel recycling plant in 2018, using robots to disassemble solar panels layer by layer and recycle silicon, silver and other components.
3. Development of photovoltaic recycling technology
As mentioned earlier, one of the main economic challenges of recycling PV panels is recycling higher-value materials such as silicon and silver. The current method of etching pure silicon from solar cells uses hydrofluoric acid, which is highly toxic and corrosive. In November last year, Indian researchers came up with a safer and more cost-effective formula that included sodium hydroxide, nitric acid and phosphoric acid. On this basis, the researchers used a three-step continuous method, which not only extracted 99.998% pure silicon, but also recovered silver.
As a result, they estimate that integrating their technology into the recycling process for 1 kilogram of solar cells would generate a profit of about $185. So where is the hope for the U.S. photovoltaic panel recycling industry? First, TG claims to have devised a heat treatment method that evaporates the protective EVA layer without damaging or contaminating the solar cells. Unlike traditional furnaces, their ovens will operate at temperatures below 500°C, effectively preventing iron and copper from penetrating the photovoltaic panel cells. Now, the startup is planning to have their first pilot plant up and running, with a goal of recycling 100,000 solar panels a year.
Giving all PV panel components a second life would not only reduce the amount of waste in landfills, but also reduce the need for new materials. In addition to increasing recycling rates and profitability, regulations should also reduce landfill accessibility. Although at an early stage, new recycling technologies could improve the recovery of valuable materials such as silicon and silver for PV modules. Optimizing market recycling of PV panels can take a long time, but it is only a matter of time. It is conceivable that once the problem of photovoltaic panel recycling is solved, there will be huge market opportunities in the future. From this point of view, the recycling of photovoltaic panels can be said to be a win-win for the economy and the environment.