By the end of 2024, the world will have approximately 2,000 gigawatts of solar capacity in operation. Each panel is made of silicon, glass, various polymers, aluminum, copper, and various other metals that capture solar energy. A good rule of thumb is that panels, unless damaged, can last up to 30 years before needing replacement. But what happens to these raw materials when our current solar panels become obsolete? Surely we’re not wasting it all, right?
What can destroy solar panels?
Conventional wisdom says that solar panels have a lifespan of around 30 years, but that’s not all. “Thirty years is the best guess,” explained Garvin Heath of the National Renewable Energy Laboratory (NREL). NREL has found that panels have a high failure rate at the beginning of their life, often due to manufacturing or installation defects. In middle age, only a small number of panels fail. Then, at the 30-year mark, the statistics start to climb northward, but the number of damaged panels is still “less than 1 percent” of all panels in operation at the time.
Matt Burnell is the founder of ReSolar, a UK start-up looking to reuse, repower and recycle solar panels. As part of his work, Burnell visited a solar farm with a 40,000-panel array where 200 panels were damaged during installation. “I took about 50 from that location and tested them to see their reuse (and) power generation value,” he said, adding that most were within “manufacturer’s tolerance range.” said. Basically, other than the odd crack in the glass or a crash in the frame (which could cause problems in the future), the panel was fully functional.
If the panels survive their birth and installation, weather is the biggest factor in destroying solar panels. Common causes are extreme weather events that damage the panels, or periodic inclement weather that degrades them, Heath said. Unfortunately, once a panel is broken, it is often not worth repairing.
Therefore, a panel that is deemed “broken” during manufacturing or installation may still be able to provide power from the sun. However, there are also many panels that are no longer in use after 25 or 30 years, even if they are not broken in any meaningful sense. There’s a very simple reason why solar power plants can’t absorb rays until these panels stop working.
It’s a question of economics, idiot.
The key issue is the loss of efficiency. This means that the panels will no longer produce as much power as they did when they were first installed. Most solar panels are made with a laminated adhesive layer between the glass and the solar cells to hold them together and increase their rigidity. Exposure to sunlight can cause these laminated layers to discolor, reducing the amount of light that reaches the cells. This reduces energy generation capacity and is a problem for large commercial farms.
“Manufacturers guarantee the performance of their (solar) modules for 30 years,” Garvin Heath explained. For example, manufacturers pledge that their panels will be at least 80% efficient for most of their expected 30-year useful life. These warranties give large power utility customers confidence in what they are buying, and that at the end of that period it is much more cost-effective to just junk it and replace it. is common.
A power grid has a limited number of interconnections, which are essentially entry ramps for power to enter the grid. Each interconnect has a strict upper limit on the power it can transmit, so a solar power plant must always produce the maximum allowable power. “The opportunity cost of having modules that interconnect to generate (more) power is extremely valuable, even if they are operating within guaranteed performance,” Heath said.
Matt Burnell from ReSolar gave the example of a 10 MW solar farm in the UK with 15 MW of interconnect. “Ten years ago, you could only install 10 megawatts in your own space (…) But with newer, more efficient modules, it is now economical to strip and rebuild assets. It’s doable.” “These big pension funds are looking at this from their spreadsheets and looking for ways to maximize their investments more effectively.” In the end, all these nice panels are junk. It will become. “It’s crazy to think about the carbon that’s embedded by bringing[the panels]in from[China]and putting them in the waste stream,” Burnell said.
Even if panels could be repaired with maximum efficiency, it is unlikely that solar panel repair shops would open in large numbers. “There are serious questions about the labor costs of testing and repair versus just purchasing new panels,” Burnell said. He added another example of panels that had to be removed to address fire safety regulations. These panels were similarly at risk of being thrown away because it would take too much effort to reuse them. To reduce waste, Resolar actually collected these panels and sold them on consignment to Ukraine for use in hospitals.
inside the trash can
Matt Burnell / Resolar
Another rule of thumb is that only 1 in 10 solar panels will be recycled, and the remaining 9 will end up in a landfill. There is no standard way to track a panel’s final destination, and it is not clear how such a system would be implemented. But there is a risk that landfills could be overwhelmed by the amount of panels falling from roofs. For example, the Los Angeles Times reported that California will have a glut of panels in the future after promoting solar installations since 2006.
Grist describes the situation in 2020 as a “wild west,” as the legal landscape is patchy, with only Washington enacting mandatory laws. Retired solar panels are subject to federal solid waste and hazardous waste regulations, depending on the materials used in their construction. If the panels contain heavy metals such as lead or cadmium, they cannot be sent to a general landfill to prevent the poison from seeping into the soil. But that often means the panels are redirected to landfills designed to handle specialty waste.
The EPA is currently considering developing rules to standardize the recycling process for solar panels and lithium batteries. But even though there is no federal recycling mandate or even strict laws at the state level, the situation is far from ideal. A small portion of the panels actually end up in recycling centers, leaving the rest to an uncertain fate. The risk, Heath points out, is that a huge amount of working solar panels will be left sitting in piles while conditions change, while recycling is uneconomical and unavailable. That’s true.
In the UK and Europe, solar panels are covered by the Waste Electrical and Electronic Equipment Directive (WEEE). The rules require suppliers to collect and recycle discarded panels, or have another company pay for it. This means that, hopefully, tons of panels won’t end up in landfills, but it’s often more economical to send working panels for recycling than to reuse them. also means
recycling
Matt Burnell / Resolar
If you want to release the raw materials hidden inside your solar panels, there are two approaches. There is also a mechanical method of shredding the parts, which is easier but wasteful, recovering glass and metal but not much else. Alternatively, there are thermal and chemical approaches that try to separate the components so that more rare metals can be recovered.
“Incumbent recyclers have traditional markets that base their economics on. So glass recyclers can look at a module and say, ‘Wow, 80 percent of the weight of the module is glass. ‘I know what to do with it,”’ Heath says. “The internal materials contain even more valuable precious metals. However, they are mixed into the polymer layer of the plastic (…) and are difficult to separate economically,” he says. said. As a result, the silicon, silver, and copper embedded in cells are often crushed into bulk and discarded.
The IEA’s 2024 report on panel recycling considers how bad these mechanical methods are for material quality. “Products from machining are usually not very pure, so we should aim to improve yields of high-quality materials, especially silicon and silver,” the report said. Additionally, these recycling processes are often not optimized for solar panel operation, which “frequently results in some reduction in the quality of the recovered material,” making it a major step on the path to circularity. He added that he couldn’t say it.
It’s also difficult to know what’s in a solar panel. “There’s a huge variation in the materials[used in solar panels],” said Matt Burnell of Resolar. Many manufacturers are not yet obliged to share raw material data, but new regulations are expected to change this soon. Until then, it is difficult for recyclers to know what will be extracted from the panels they are processing.
Not only do recyclers not know the composition of the panels, there is also a risk that harmful chemicals may be added to facilitate some processes. Antoine Chalaux is the General Manager of ROSI Solar, a French specialist solar panel recycler. He talked about the chemicals it contains, such as Teflon and antimony. Both of these chemicals are toxic and cannot be released into the atmosphere. “We have developed recycling processes to recover (them), but we are putting pressure on (manufacturers) to reduce their use (in the future),” he explained. did.
Burnell believes the industry is truly in the “early days” of solar recycling, but with today’s investment he is confident that a solution will soon be found in the near future. “We have such a long implementation period that we know what’s coming to the market today and what’s going to be in the system 25 to 30 years from now,” he said. The real ticker is the excess panels installed in the early 2010s that will start entering the waste stream in the next decade.
At the moment, ROSI’s process isn’t as cheap as other recyclers, and Shallow acknowledges that could be a problem. “At the moment there is no economic reason for companies to[work with us to recycle]but there is an image issue,” he said. “Every manufacturer and owner of a solar project wants a good end-of-life story for their panels.” However, another benefit of this process is the high purity Being able to generate recycled materials.
future
Graphic: Al Hicks/NREL
One step toward more recyclable solar panels may be to eliminate the use of these adhesive polymers when constructing panels. If the panels could be made of glass sheets with solar cells inside, disassembly would be much easier. Not to mention, there’s no polymer layer to discolor, so you’re likely to get better performance for longer.
Thankfully, a team at the US National Renewable Energy Laboratory (NREL) has demonstrated that such a product can exist. Rather than gluing layers together, a femtosecond laser welds the glass front and back panels together. The solar cell is sandwiched inside, held in place by a glass bond to its sibling and nothing else. And when the panels eventually reach the end of their lifespan, which can be well over 30 years, they can be recycled by simply crushing the glass.
The project, led by Dr David Young, says if the proposal is accepted, a commercial version of the panel could be seen within two to three years. He added that the rigidity provided by welding makes it as strong and waterproof as panels using polymer layers. Unfortunately, at that point, there are still decades of panels manufactured using the old system that need to be addressed. And until we find cost-effective and scalable recycling methods, we won’t have an answer to the question, “What happens when a solar panel dies?” It means “nothing is good”.
