There are two reasons people install solar panels on their homes. The first is cost; they want to save on their energy bills. But there’s also the environment. Solar power supporters want an energy source that doesn’t pollute. If that’s part of your motivation, you will want to think about what happens when your solar panels wear out. Can you discard the old panels in a way that is kind to Mother Earth?
When it’s time to get rid of old solar panels, you have three choices: you can throw them in the landfill, have them recycled, or repurpose them. The landfill is the worst option and is already prohibited in some places, while solar panel makers are working on better recycling methods.
Most of you bought solar panels at least in part because you wanted clean energy. Letting worn-out solar panels foul the soil and water defeats the whole purpose. The good news is that solar panel makers are working on ways to recycle old panels. And old panels still have some value, so we may not need to recycle or discard all of them. You have several options here. Let’s look at them one-by-one.
Option One: The Dump
In most of the United States, old solar panels usually go into landfills without any attempt to salvage any materials or parts. This isn’t a disaster, but it isn’t a good long-term solution either. Solar panels contain some poisonous materials, especially lead and cadmium. Lead is well known for causing brain damage, while cadmium exposure has linked to lung and other types of cancer.
The Resource Conservation and Recovery Act determines whether or not your solar panels can be sent to a landfill. The Environmental Protection Agency has set up what it calls “Toxicity Characterization and Leaching Procedure” guidelines, and as of now old solar panels pass. As long as that remains the case you can still throw them away safely and legally.
The amount of lead and cadmium in individual solar cells isn’t extremely high, and solar technology is still relatively new in the US. At present there are relatively few solar cells being taken offline, so the danger is not particularly acute. But as we rely more on solar power, we will have more solar panels coming to the end of their life cycles.
The risk that toxins from used solar panels will leak into soil and groundwater is bound to increase. The crunch will likely come in about 30 years when panels that are entering service now will be ready for replacement. By 2050 there could be as much as 80 million tons of solar-power-related waste in landfills worldwide.
States are aware of the issue, and they are taking steps to head off the danger. The State of Washington already requires that solar panel manufacturers recycle the panels they sell. California has also established regulations that treat solar cells much like batteries and other electronic devices, encouraging recycling over landfilling.
Still, most solar panels in the US wind up in landfills after they are taken down. This might be tolerable in the short run. Over the long haul we will need to find better solutions. Fortunately, solar engineers have made a lot of progress in recycling used panels.
Option Two: Recycling
Europe has taken the lead here. Under the European Union’s Waste Electrical and Electronic Equipment (WEEE) Directive, solar panel makers are required to take back and recycle all of the panels that they sell throughout the continent.
Panel makers have responded by creating companies that specialize in breaking down panels into basic materials. Most have joined the PV Cycle network, which has worked out a process for recovering up to 96 percent of a solar panel’s parts and making them available for reuse.
The US is well behind Europe in recycling, so if you want to recycle solar panels, you can’t drop them off at any recycling center. You will need to transport your panels to one of a handful of companies in the US specializing in solar panel recycling.
You may want to reach out to Solar Energy Industries of America, which is developing its own network of recyclers. If you can’t find one of those, your next best option is to find a glass recycler, which should at least be able to handle the glass screen and most of the metal parts.
How Solar Panels Get Recycled
Recycling a solar panel begins by dismantling the outer casing. The glass front can be ground down and eventually melted to be remade into glass items such as windows or glass bottles. The aluminum frame is used as scrap metal.
Inside the panel, there will be mounting brackets that hold internal components in place, plus the back panel that is frequently made of polyvinyl fluoride. These can be recycled for a whole range of plastic goods, or they can even be used as fuel in specially designed ovens that are used in the cement-making process. Copper wiring is stripped and melted down into “shot” that can be used for just about anything made with copper.
That leaves us with the actual solar cells, the real guts of the solar panel. These are wafers of crystalline silicon laced with other chemicals that create current when exposed to light. This is also where you will find the heavy metals like lead that present the biggest challenge to our environment.
These cells are a bit on the fragile side, so frequently they can be broken down by shaking them. Then they are chemically treated to separate the silicon from other materials. The silicon can then be reused to make semiconductors for electronic chips or even new solar cells.
The process is a little bit different for solar films. These are thinner and have much less glass and aluminum than traditional solar panels. The process for these starts with shredding the film into small pieces, less than 1/4 inch across. Then the recycler will use a combination of chemicals and mechanical processes to separate silicon from lamination and glass. The process recovers 95 percent of the silicon and 90% of other materials.
The Future of Recycling
There are still challenges to be overcome, especially in the US. Too many panels here are being warehoused, waiting for a recycler that can handle them. Recycling solar panels will still need economic incentives; it is significantly cheaper to make solar panels with all new materials than with recycled materials.
Panel manufacturers continue to develop more efficient and cheaper panels. This is good news for consumers but makes life complicated for recyclers, who must learn to deal with many makes and models of solar panels, each with its unique combination of designs and materials to extract.
Panel makers are also working on designing panels that are easier to recycle. One promising development is the invention of perovskite solar cells. These cells are easier to break down chemically than silicon, and do not necessarily need poisonous additives like lead or cadmium. The next generation of solar cells could be greener and a lot easier to reuse.
But solar power supporters in the United States can take comfort from knowing that engineers in North America and Europe are working on the problem. We already have the basic processes worked out to the point where nearly all of the materials in a solar panel can be reused, and we have twenty years before the bulk of the solar panels in use today will need to be taken down. That’s plenty of time to refine our methods and make recycling profitable.
Option Three: Reuse
Solar Panels don’t just conk out all at once. While they do lose efficiency over time, it’s a gradual decline, not a sudden drop. Most solar panels will lose less than one percent of their power generation capacity over a year. After 25 to 30 years, solar panels will still generate 80 to 85 percent of the power that they did when they were first installed.
That’s the point where most commercial solar generation plants and residential solar users will want to replace them. But while it might make sense for you to replace those panels, that doesn’t mean the old panels are worthless. They still generate power, and research in old panels shows that many of them will “bottom out” at around 80 percent and stay at that level for another decade or longer.
In fact, old solar panels are valuable enough to have a bit of a black market for them. In one case solar panels slated for recycling in Italy were fraudulently shipped to North Africa instead.
Charities have shown that solar-powered lighting can be extremely valuable to communities in places like rural Africa, where the electrical grid is unreliable or nonexistent. Without solar power many poor families have to rely on kerosene lamps or candles for light at night. The light they provide is dimmer than electrical lights, and the open flames create fire hazards.
Solar electricity provides better light and is a lot safer. An old solar panel that is past its peak over here could be a life-saver elsewhere. If you want to help, you might find a charitable group that will put them to good use.
There is a bit of a market opening up for used solar panels: Energy Bin is one organization, made up mainly of solar installers, retailers, and other businesses, who buy and sell older solar equipment. Many companies can make do with equipment that isn’t state of the art, so you might find a buyer for your old panels.
Option Four: Leave ‘Em Up There
This brings up another possibility for a family to consider if they are worried about the effects that old solar panels will have on the environment: accept the dropoff in power production and continue using their older solar panels, replacing damaged panels as needed but leaving intact panels in place as long as they continue to function.
Stretching out the working life of solar panels would make the solar industry a bit greener. There would be fewer panels going into landfills or recycled every year, and fewer new panels would need to be made. This is a tradeoff that many families won’t want to make. Space on your roof is limited, and your need for power might increase even as the output from your solar panels tapers off.
But leaving older panels in place will save you the up-front cost of purchasing new panels and having them installed. Depending on your household’s electrical demand, it could be a reasonable way to go if you are worried that your solar panels won’t be recycled properly. At the very least you should not let yourself be pushed into replacing your panels before you are ready to.
If you are concerned about the environment, solar power is a great way to generate the electricity you need. But at the same time, solar panels do contain some poisonous materials that could harm the soil and water if they leaked out. It’s fair to ask if your solar panels themselves might harm the environment when it’s time to take them down.
The good news is solar panel makers in Europe and North America are already working on the problem. Recyclers can already recover 96 percent of the materials in solar panels and are developing methods to make the process even more efficient and economical.
In addition, solar panels don’t just die after 20 years of service. They continue to generate power — less than before, but still enough to be useful in the right circumstances. This creates the possibility for older solar panels to be reused. You might even decide to keep yours running for a few extra years.
So you shouldn’t worry too much about pollution from used solar panels. When it’s time to replace your panels, you will have earth-friendly options to choose from. If you care about the environment, solar power is still the best way to go.