Peak solar recycling season is here.
Are you ready to recycle your modules damaged from extreme weather, construction breakage, or something else?
No, but I want to learn more about SOLARCYCLE
We often hear the phrase “tons recycled” used to quantify the impact of recycling. It’s a good number, but this single metric leaves out valuable information that affects our ability to measure our progress and ultimately achieve our mission of circularity for solar. To effectively evaluate a circular economy, where retired solar panels are inputs and recovered materials are outputs, we need to know more than just the weight of the materials dropped off at the recycling facility.
The industry doesn’t yet have a standard way to measure impact for end-of-life (EOL) solar, so we’ve established our own criteria, looking at the following:
We tend to view recycling as a one-to-one substitute for landfilling. As a result, we may be inclined to use the same metric: the amount of waste product sent to the landfill. But this framework remains squarely within the bounds of the linear economic model that centers on the original product and assumes an absolute end point.
In a circular model, we also care about the products generated from the recycling process. Like any manufacturing process, the recycling process incurs some material losses while transforming inputs to outputs. Quantity in does not equal quantity out, and both quantities are imperative to capture the full extent of how much material has been recycled.
“How much”, therefore, can be measured by how much is collected and sent to the recycling facility, how much is processed on our recycling line, and how much is recovered and reintroduced to the supply chain. Each data point tells a different story, which is why we track input and output quantities across all stages of our recycling process.
“What is the value” is our next consideration. To answer this, we have to examine the quality of output materials in context.
While a retired solar panel has little remaining value as a panel, its many material constituents (e.g., aluminum, silver, silicon, copper, glass) are individually valuable. Despite their intrinsic value, these materials are worthless to the market until they are separated and recovered. Then, their value manifests in several ways––price is one, but materials carry environmental and social value as well.
Take silver, for example, which has the highest per pound monetary value in a crystalline silicon (c-Si) solar panel. Silver’s high price tag is largely derived from demand, scarcity, and the energy-intensity of its production. The solar industry already consumes over 15% of global silver supplies today and is on track to consume 85-100% in the next two decades, meaning the value of silver will only increase.1
Aluminum, on the other hand, is not as expensive, but according to the World Bank, aluminum for solar panels is by far the single largest driver of climate impacts from transition minerals. It is higher than all battery minerals combined.2
If we were to use a single weight metric, like “ton” to quantify the impact of recycling these metals, we would lose this context and limit our understanding of what it means to recycle a solar panel and what kind of value it drives.
To put this in perspective with another example, the approximate ratio of silver to glass content by weight in a solar panel is 1 to 2,000. The approximate relative value (USD) of silver to glass is 5,000 to 1. How much value are we recovering if we know we processed 1 ton of material, but don’t know if the silver was recovered along the way? Something so small suddenly carries quite a lot of weight––pun intended! We address this by incorporating both price and life cycle environmental impacts of each constituent into our material recovery metrics.
The final piece of the puzzle, “Where does it go” looks beyond SOLARCYCLE’s facilities and tells us whether the value of each material output is maintained as it moves through the circular supply chain. The materials in c-Si solar panels are not particularly niche and can be found in the raw material streams of many industries. So, the potential uses for recycled solar panel constituents are broad and the lifecycle benefits from recycling can vary.
If we want to optimize the circular economy, it requires minimizing downcycling of outputs and avoiding landfilling as much as possible, particularly for high-purity materials.
For example, recycling solar glass to make a bottle or asphalt avoids landfilling. But so does recycling the glass to make new solar glass. Which is preferable then? Looking just one step deeper, you’d find that the energy and resources that went into sourcing low-iron sand and producing the original glass to solar-grade purity are lost when it is downcycled into a product (e.g., bottle) that requires less purity. Considering the system in greater depth is only the first step. The second is actually unlocking that downstream capacity to produce value-equivalent or value-added second-life products.
We’re serious about our mission––to advance the circular economy for solar. We currently return recovered material to the supply chain as fiber glass, scrap metal, and precious metals, and we’re making excellent progress at our solar glass plant in Georgia where we’ll manufacture new solar glass from recycled solar glass.
In solar panel recycling, the whole is not greater than the sum of its parts. While the mass of “whole” panels diverted from landfills is interesting and important, it is a one-dimensional way to measure impact. The individual constituents of an EOL solar panel have much more value when they are separated into distinct, usable “parts”.
To capture the true impact of solar panel recycling, the solar industry needs to know how much is recycled, what is the value, and where the material goes. For example, since our founding, SOLARCYCLE has recycled 92,173,191 lbs of solar panels, helping to avoid 186,445,045 kg CO2e. This includes recovering 77,361,984 lbs of glass, which is enough glass to make approximately 1,880,000 new solar panels.
With this information in hand, we can start to get into even bigger-picture discussions around the global impacts of recycling––from mitigating climate change, to slowing the growth of ever-expanding landfills, regenerating supply chains, and securing a solar-powered future.
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1 Hallam B, Kim M, Zhang Y, et al. (2022). The silver learning curve for photovoltaics and projected silver demand for net-zero emissions by 2050. Prog Photovolt Res Appl. 2023; 31(6): 598-606. doi:10.1002/pip.3661
2 World Bank (2020). https://pubdocs.worldbank.org/en/961711588875536384/Minerals-for-Climate-Action-The-Mineral-Intensity-of-the-Clean-Energy-Transition.pdf
