Solar Waste Management: Opportunities & Challenges

Millions of solar panels have been installed in the last two decades and since they typically last between 25 and 30 years, many will soon be ready for retirement and probably headed to a landfill. However, new efforts to recycle these panels could reduce both the amount of waste and the new material that needs to be mined. About 8 million metric tons of decommissioned solar panels could accumulate globally by 2030. By 2050, that number could reach 80 million.
 
About 90 percent of commercial solar panels use silicon as the semiconductor, which converts light into electricity. Thin strips of metal, usually silver, crisscross the surface of silicon crystals in each cell and move electricity into the panel’s copper wiring. The solar cells are encased in a protective barrier, usually a transparent plastic called EVA. Another layer of glass goes on top, and a different kind of plastic, like PET, covers the back. The whole thing is surrounded by an aluminum frame. This layered construction protects cells from the elements while allowing sunlight through, but it can be difficult to deconstruct when the panels have reached the end of their life.
 
Some companies try to refurbish and reuse panels that have lost efficiency, or at least rescue some of their components. Reuse is the simplest and cheapest way to ‘recycle’ panels it requires the least processing and commands the highest price.
 
Used panels don’t generate as much electricity, so the money saved by buying them might not be worth it. Used panels that can’t be resold are destined for either the landfill or some type of recycling. The solar waste recycling process pops off the aluminum frame and grinds all the glass, silicon, and other metals into a mixture called glass cullet, which can be sold for building materials or other industrial applications. But cullet isn’t worth much for a panel’s worth of the mixture. And it’s not clear if there will be buyers for all the cullet. Being able to extract pure, valuable materials might help make recycling more profitable.
 
Because silver is so expensive and limited, some researchers are working to reduce or even replace silver in new solar panels. What remains to be seen is the environmental impact of the recycling efforts themselves. Quantifying the effects, they will have on pollution and emissions can help in deciding on the best approach to the solar-waste problem. Exactly how a panel is manufactured and recycled helps determine how helpful it really is in decreasing emissions.
 
The energy industry has been experiencing a radical change and the gradual shift towards renewable energy sourcing is more than evident. During the life of photovoltaic panels, a 20 percent decrease in power capacity might occur. Between the first 10 to 12 years, the maximum decrease in efficiency is 10 percent, and 20 percent when reaching 25 years.
 
Since all PV cells contain a certain amount of toxic substances that would truly become a not-so-sustainable way of sourcing energy. Research studies conducted on the topic of recycling solar panels have resulted in numerous technologies. Some of them even reach an astonishing 96 percent recycling efficiency, but the aim is to raise the bar higher in the future.
 
In fact, a study by the International Renewable Energy Agency (IRENA) estimates the recyclable materials in old solar modules will be worth USD 15 billion in recoverable assets by the year 2050. The common belief of solar panels not being recyclable is, therefore, a myth. It is, however, a process that needs time to be widely implemented and requires further. Here are the main steps involved in successfully recycling a silicon module:
 

 
Now that we know that solar panels can be recycled, the question is what other benefits it brings to the economy. We, at Navitas Solar, a solar module manufacturing company with the capacity of 2 GW p.a. offering modules from 40 to 720 watts per panel believe that a proper solar panel recycling infrastructure needs to be established to manage the large volumes of PV modules that will be disposed of in near future. Once that is in place, we will be witnessing several positive factors and new opportunities within the economy.
 

- Navitas Solar, Co-Founder & Director, Navitas Solar