When we look at solar panels, most questions we get asked are about cost, efficiency, technology and about the future of solar energy in a wider sense. We mostly forget to ask about what happens at the end of a solar installation’s lifespan. We want to know how long an installation will work for us but we fail to ask about what happens to the physical product once it needs to be replaced. As a provider and installer of solar panels and an enthusiastic advocate for installing these systems, Caldor Solar want to offer a full picture of a product’s life cycle from beginning to end. Here we are, at the end; what happens to solar panels at the end of their life?
The Renewable Energy Industry
The energy industry as a whole, has been shifting towards renewable energy sources in recent times. With that comes its own range of sustainability issues that need to be addressed. The system itself might offer a green solution to generating power but we need to pull back the curtains to find out about the processes both during the manufacturing stage and the end of life stage. We don’t utter a magic word to have them disappear, so, where do they go?
We know (and you will too, if you’ve been following our blog) that solar panel systems can last upwards of 25 years before decommissioning. Far enough into the future to avoid thinking about their end of life care. And, it’s not an abrupt end to their service. Between the first 10 to 12 years, the maximum decrease in efficiency is 10%. That decrease hits 20% when in reach of 25 years. It’s still a relatively new industry but from what we have learned to date, the efficiency drops by a mere 6-8% after that 25 years so they can be used for longer than we’re officially told. We just can’t expect the same performance.
But, that still shouldn’t distract us from the bottom line of this blog. What happens to them when you do decide to give them up?
Disposal Of Solar Panels
There are rules in place to help us do as much as we can when it comes to getting rid of our solar panel systems. From a regulatory perspective, PV panel waste falls in the category of general waste. Thankfully, a sole exception exists at EU-level, where PV panels are classified as e-waste in the Waste Electrical and Electronic Equipment (WEEE) Directive. That directive helps guide us, in addition to other legal frameworks.
Manufacturers of solar cells are held to account, by law, to fulfil a certain set of legal requirements in order to make sure that solar panels do not become an environmental burden. However, we have to admit that with an estimated 60 million tons of PV panels lying in landfills by 2050 these recycling processes need not only to be in place but invested in and improved upon.
Since all PV cells contain traces of toxic substances, the good work they do could be mired through irresponsibility when it comes to their disposal. While they are recyclable, investment is needed in order to make this widely implemented and to reach its full potential. The good news is that producers of solar panels are collaborating with governmental institutions in order to address these issues.
The Current Solar Panel Recycling Processes
As you may know, there are three types of solar panels – the two most common are silicon based and thin film based. Each variety requires a different approach when it comes to recycling.
For silicon based PV panels, it starts with disassembling the system into aluminium and glass parts. Nearly all of the glass can be reused while all the metal parts are broken down for re-moulding cell frames. The remaining materials go through a 500°C thermal processing unit to separate the binding between the cell elements. The heat allows the silicon cells to be further processed while the supporting technology further ensures that the plastic waste is also reusable as a heat source for further thermal processing.
In comparison, when dealing with the disposal of thin-film based solar panels, it’s a little more aggressive. They first go through a shredder, then a hammermill makes sure that all particles are smaller than 5mm.
Thin-film cells contain both liquid and solid material and these are separate using a rotating screw. This keeps the solid material rotating in a tube while allowing the liquid to drop down into a container. That liquid then goes through a precipitation and dewatering process to ensure purity before undergoing a metal processing to completely separate the different semiconductor materials. The remaining solid matter is rinsed after being contaminated with interlayer materials (which are lighter in mass and removed through a vibrating surface). Finally, what is left behind is pure glass which goes back into remanufacturing.
The Future Benefits of Solar Waste Management
While it’s good to know that solar panels can be recycled albeit with a long sounding list of steps and processes, it’s important to push the information out and make it available to people on a larger scale. A strong recycling infrastructure will be needed to manage the expected volumes over the coming years and in Ireland, installation companies contribute annually to ensuring that infrastructure is being held accountable.
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