Many of us are making the move towards solar panels to reduce our energy bills and create greater energy security but another great benefit is in reducing our carbon footprint. So, if we get solar panels for environmental reasons then it is important to consider the long-term environmental impact of our decision making. So here we answer the question: can solar panels be recycled?
Solar panels have a life expectancy of up to 30 years +
Firstly, let’s start with some really good news! Solar panels have a guaranteed life-expectancy of over 25 years, which means that panels that are fitted now are expected to last up to 30 years with only a small drop in efficiency. Just give them a clean once or twice a year and they should serve you well. But when the time does come for a replacement of solar panels, or if you have inherited an older system that is likely to need replacement at some point don’t fret because the infrastructure is now in place to recycle the panels effectively.
Manufacturers predict a maximum 20 per cent loss in efficiency over the life of the solar panels. This is suggested to be up to 10 per cent over the first 10 years reaching 20 per cent by 25 years. This is guaranteed by the majority of manufacturers.
In reality, the drop in efficiency is actually much lower at only 6 to 8 per cent after 25 years. The manufacturers guarantee is 25 years but the actual life-span of the solar panels is potentially much longer, perhaps even reaching 30 to 40 years.
Disposal of solar panels
When the time does come to dispose of solar panels the manufacturers are bound by law to fulfil specific legal requirements and recycling standards in order to make sure that solar panels do not become a burden to the environment. And technologies to recycle solar panels are developing rapidly. Solar panel producers, working with governmental institutions, have come up with ways to tackle solar waste.
So, how can solar panels be recycled?
It is predicted that if recycling processes were not put in place, there would be 60 million tons of PV panels waste lying in landfills by the year 2050. This obviously requires a coordinated effort from manufacturers and governments to sign post a process that works well and is mutually beneficial. But most of the solar panel and associated batteries are recyclable.
Recycling processes for photovoltaic panels
There are two main types of solar panels, requiring different recycling approaches. Both types—silicon based and thin-film based—can be recycled using distinct industrial processes. Currently, silicon based panels are more common, though that does not mean that there would not be great value in the materials of thin-film based cells. Research suggests that a 96% recycling efficiency can be reached, but the aim of the industry is to continue to improve this figure.
Silicon based solar PV panel recycling
Silicon based PV panels require normal flat glass treatment and no special removal of the semi-conductor layer.
- Remove cables, plug and semiconductor
- Separate aluminium and glass from the PV module
- Remove labels
- Reuse or recycle the EVA film and recover chemical elements such as cadmium and selenium
- Separate into fractions (EVA film, Aluminium, Wafer, Cable and plastic plug, Semiconductor, Glass)
- Recycle the glass fraction in a smelter
The recycling process of silicon-based PV panels starts with disassembling the actual product to separate aluminium and glass parts. Almost all (95%) of the glass can be reused, while all external metal parts are used for re-molding cell frames. The remainder materials are treated at 500°C in a thermal processing unit in order to ease up the binding between the cell elements. Due to the extreme heat, the encapsulating plastic evaporates, leaving the silicon cells ready to be further processed. The supporting technology ensures that not even this plastic is wasted, therefore it is reused as a heat source for further thermal processing.
After the thermal treatment, the green hardware is physically separated. 80% of these can readily be reused, while the remainder is further refined. Silicon particles—called wafers—are etched away using acid. Broken wafers are melted to be used again for manufacturing new silicon modules, resulting in 85% recycling rate of the silicon material.
Thin-film based solar panel recycling
In comparison, thin-film based panels are processed more drastically. The first step is to put them in a shredder. Afterwards, a hammermill ensures that all particles are no larger than 4-5mm, which is the size where the lamination keeping the inside materials together breaks, and hence can be removed. Contrary to silicon-based PV panels, the remaining substance consists of both solid and liquid material. To separate these, a rotating screw is utilised, which basically keeps the solid parts rotating inside a tube, while the liquid drips into a container.
Liquids go through a precipitation and dewatering process to ensure purity. The resulting substance goes through metal processing to completely separate the different semiconductor materials. The latter step depends on the actual technology used when producing the panels; however, on average 95% of the semiconductor material is reused.
Solid matters are contaminated with so-called interlayer materials, which are lighter in mass and can be removed through a vibrating surface. Finally, the material goes through rinsing. What is left behind is pure glass, saving 90% of the glass elements for easy re-manufacturing.
The future benefits of solar waste management
A solar panel recycling infrastructure is developing to manage the large volumes of PV modules that will be disposed in near future.
Not only will Solar PV recycling create more green job opportunities but also approximately £11 billion in recoverable value by 2050. This influx will make it possible to produce 2 billion new panels without the need to invest in raw materials. This means that there will be the capacity of producing around 630 GW of energy just from reusing previously used materials.
Companies such as recyclesolar.co.uk , based in North Lincolnshire, offer a full collection and recycling service serving the whole of the UK and Ireland. They collect panels, inverters and batteries too for recycling. They can decommission, dismantle and recycle.
Thanks to constant solar equipment price drops of up to 80% in recent years, more and more households and businesses are choosing to invest in solar power systems. As a result, even more economic opportunities in the solar cell recycling sector will emerge.