By the end of 2024, the world will have nearly 2,000 gigawatts of solar power capacity. Each panel is made of silicon, glass, various polymers, aluminum, copper, and a variety of other metals that capture solar energy. A rule of thumb is that, barring damage, panels will last up to 30 years before they need to be replaced. But what happens to all that raw material when our current solar panels become obsolete? Sure, we just waste entire, we are?
What Kills Solar Panels?
Conventional wisdom says solar panels should last about 30 years, but that’s not the whole story. “30 years of our best guess” explained Garvin Heath of the National Renewable Energy Laboratory (NREL). NREL found that panels are more likely to fail due to manufacturing or installation defects early in their life. By mid-life, only a small number of panels fail. The following statistics start to go north as you approach 30 years, but even then the number of broken panels is “less than 1%” of all panels in operation at that time.
Matt Burnell is the founder of ReSolar, a UK startup researching the reuse, repowering and recycling of solar panels. As part of his work, Burnell visited a 40,000-panel array solar farm, where 200 panels were damaged during installation. “I took about 50 of them from the field and tested them to see their value for reuse (and) power generation capacity,” he said. Most of them were within the manufacturer’s tolerances. Essentially, the panel worked flawlessly, although it could cause issues with the odd crack in the glass or bumps in the frame.
If the panels survived birth and installation, the biggest factor that kills solar panels is weather. Heath said common causes are panel damage due to extreme weather events or even deterioration due to regular, aggressive weather. Unfortunately, once a panel is damaged, it is often not worth repairing.
Therefore, panels that are considered “broken” during manufacturing or installation may still be very capable of producing power from the sun. However, there are many panels that are taken out of service after 25 or 30 years, even if they are not broken in any meaningful sense. There is a very simple reason why these panels do not allow the solar power plants to absorb rays until they simply stop functioning.
It’s the economy, you idiot.
The key issue is loss of efficiency, which occurs when the panels are no longer able to produce as much power as when they were first installed. Most solar panels are made with a laminated adhesive layer that sits between the glass and the solar cells, holding them together and increasing their rigidity. Exposure to sunlight can discolor the laminated layers, reducing the amount of light that can reach the cells. This reduces energy production capacity, a problem for large commercial farms.
“Manufacturers guarantee the performance of (solar) modules for 30 years,” explains Garvin Heath. For example, manufacturers promise that panel efficiency will be at least 80% over the expected 30-year service life. These warranties give large utility-scale customers confidence in the products they are purchasing, and at the end of their term it is often much more cost-effective to simply dispose of them and replace them.
A power grid has a limited number of interconnections, essentially lamps that can supply power to the grid. Each interconnect has an upper limit on the power it can transmit, so solar farms must always generate the maximum power allowed. “The opportunity cost of having modules producing (more) power on the interconnect (even when working within guaranteed performance) is very significant,” Heath said.
ReSolar’s Matt Burnell used the example of a 10-megawatt solar farm in the UK with 15-megawatt interconnections. “Ten years ago, you could only install 10 megawatts in the space you had (…) but with newer, more efficient modules, it is now financially feasible to decommission and rebuild assets.” “We look at large pension funds through spreadsheets” to find ways to further maximize their investments. The end result is that all your otherwise decent panels are thrown away. “If you think about the carbon that’s embedded in the process of getting (the panels) out of China and going into the waste stream (…) it’s crazy,” Burnell said.
Even if the panels could be repaired to maximum efficiency, solar panel repair shops are unlikely to open in droves. “There are serious questions about simply purchasing new panels versus the labor costs of testing and repairing them,” Burnell said. He added another example of a panel that had to be removed to address fire safety laws, which was also at similar risk of being scrapped because efforts to repurpose it were so great. To reduce waste, ReSolar actually stopped collecting and shipping those panels to Ukraine for use in hospitals.
in the trash can
Another rule of thumb is that only 1 in 10 solar panels are recycled, with the remaining 9 ending up in landfill. There is no standard way to track the final destination of a panel, and it is not clear how such a system would be implemented. However, the volume of panels coming down from roofs threatens to overwhelm the landfill. Los Angeles TimesFor example, it was reported that there would be a panel glut in California after the state began pressuring the state to install more solar power in 2006.
The legal situation is rarely patchwork. grist We describe the situation in 2020 as “the Wild West” because only Washington has some sort of mandatory legislation. Discarded solar panels are subject to federal solid and hazardous waste regulations, depending on the materials used in their construction. If the panels contain heavy metals like lead or cadmium, they cannot be sent to a regular landfill to prevent the poisons from seeping into the soil. However, this often means that those panels are redirected to landfills designed to handle specialist waste.
EPA is currently considering developing rules to standardize the recycling process for solar panels and lithium batteries. But without a federal mandate for recycling or even strict legislation at the state level, the situation is far from ideal. In reality, some of the panels are sent to recycling centers while others face an uncertain fate. As Heath points out, recycling is uneconomical and impossible, but while things change, there’s a risk that we’ll end up with a huge skeleton of working solar panels stacked on top of each other.
In the UK and Europe, solar panels are subject to the Waste Electrical and Electronic Equipment (WEEE) Directive. The regulations require suppliers to collect and recycle discarded panels or cover the cost of having another company do this. This hopefully means we won’t see more panels ending up in landfill, but it also means it’s more economical to recycle working panels than to repurpose them.
recycling
There are two approaches to securing the raw materials hidden inside solar panels. There are mechanical ways to shred parts, which are simpler and less wasteful. Glass and metal can be recovered, but little else. Alternatively, there are thermal and chemical approaches that separate the components, allowing more rare metals to be recovered.
“Incumbent recyclers have a traditional market to base their economy on, so a glass recycler looks at a module and says, ‘Wow, 80 percent of the weight of the module is glass, I know what to do with it,’” Heath said. “The inner material contains more precious metals of higher value, but they are mixed with layers of plastic polymers (…) that are economically difficult to separate,” he said. As a result, the silicon, silver, and copper embedded in the cells are often pulverized and discarded in large quantities.
The IEA’s 2024 report on panel recycling examined how these mechanical methods are detrimental to material quality. “The output of machining is generally not very pure and better yields of high-quality materials (…), especially silicon and silver, should be targeted,” he said. Because these recycling processes are often not optimized for running solar panels, “the quality of the recovered material is often compromised,” he added. This is not a huge step towards circularity.
It’s also difficult to know what goes into a solar panel. “Changes in materials (found in solar panels) wild“Many manufacturers are not yet required to share raw material data, but that will soon change under new regulations. Until then, it’s difficult to know what recyclers will get out of the panels they’re trying to process.”
Not only do recyclers not know what the panels are made of, but there’s also the risk of hazardous chemicals being added to expedite some of the processes. Antoine Chalaux is General Manager of ROSI Solar, a French solar panel recycling specialist. He talked about including chemicals such as Teflon and antimony that are toxic and cannot be released into the atmosphere. “We have developed a recycling process to capture (them), but we are pushing (manufacturers) to use less of it (in the future),” he explained.
Burnell believes the industry is indeed at the “very dawn” of solar recycling, but is confident that investments now will allow solutions to be found quickly in the near future. “We have a huge lead-in time, so we know what’s going to be in the market today, and we know what’s going to be in the system 25 to 30 years from now,” he said. The real ticking clock is when excess panels installed in the early 2010s will start entering the waste stream within the next decade.
Currently, ROSI’s process isn’t as affordable as other recyclers, and Chalaux knows that can be a problem. “There is no economic reason for companies to recycle (with us) right now, but there is an image problem,” he said. “Every manufacturer and owner of a PV project wants a good story about the end-of-life of their panels.” However, another advantage of this process is that it produces high purity recycled material that can be used by local manufacturers.
future
One step toward more recyclable solar panels could be eliminating the use of adhesive polymers in their construction. If the panels could use sheets of glass with solar cells sandwiched inside, disassembly would be much easier. Not to mention you get longer and better performance since there is no polymer layer to discolor.
Fortunately, a team at the US National Renewable Energy Laboratory (NREL) has proven that such a product could exist. Instead of gluing layers together, the femtosecond laser welds the front and back panels of glass together. The solar cells are fitted inside and held in place by a bond of glass and brethren and nothing else. And when the panel’s lifespan eventually becomes much longer than 30 years, the glass can be broken and recycled.
The project, led by Dr David Young, says it could see a commercial version of the panel within two to three years if its proposal is accepted. He added that the rigidity provided by welding makes it as strong and water-resistant as panels using polymer layers. Unfortunately, at that point we will still have decades worth of panels made using outdated systems that we will have to deal with. And until we have a cost-effective and scalable way to recycle, the question ‘What happens when my solar panels die?’ is answered. ‘Nothing will be good.’
