The global shift to renewable energy has given rise to the issue of growing waste that may or may not be recyclable. As the efficiency of solar photovoltaic panels continue to get better, many of the older ones will become obsolete.Can we reuse them to yield as much value as the more efficient modern PV panels? Do they really need recycling? Let’s find out.
We have already generated about 43,500 tons of waste out of the 4 million tons of total solar PV installed by the year 2017. It has been predicted that the amount of PV waste will rise to about 60 million tons by 2050.
The global PV Cycle network offers waste management for solar PV manufacturers. According to manufacturers, technologies are evolving to make recycling possible on solar panel failures, glass breakage and electrical faults.
There are 2 types of solar panels that have been popular with manufacturers – silicon based panels and thin-film based panels. Both of them have different manufacturing as well as recycling methods.
Materials required for manufacturing a silicon based solar panel include 76% glass, 10% plastic, 8% aluminium, 5% silicon and 1% other metals. On the other hand, the materials required to manufacture a thin-film based solar panel include 89% glass, 4% plastic, 6% aluminium and 1% other metals; which is quite similar apart from the higher volume of glass.
The differences in the materials used lead to differences in the process of recycling.
1. Recycling Process of Silicon based solar panels
In the first step of the recycling process of silicon based solar panels, we have to disassemble aluminium and glass parts. Then, we have to process the remaining parts thermally at a temperature of 500° C.
The covering plastic evaporates in this process. We can use the evaporating plastic as a source of heat. In a normal recycling process, we reuse 80% of the solar panel after etching away the silicon wafers.
Then, we melt the broken wafers in order to reuse them for building new solar panels.
2. Recycling Process of thin-film based solar panels
In the first step of recycling, we must shred the thin-film based solar panels into 4-5 mm sized pieces to remove lamination. Then, we need to use a rotating screw to separate solid and liquid by adding dilute sulphuric acid and hydrogen peroxide.
We then have to separate glass from the larger pieces of ethylene vinyl acetate (EVA). The EVA is then deposited in a conveyor and collected, allowing the glass to fall into a chute where it is taken for rinsing. After collecting the glass deposited in containers, we have to pump water to a precipitation system and recover metals.
Once the metal solids settle down, we send those for processing into semiconductor grade materials to ensure its usability in manufacturing of new solar panels.
In order to make solar energy beneficial to the environment, we must avoid dumping them in landfills. We can use about 96% of materials from discarded solar panels to manufacture new solar panels, thereby minimizing environmental damage as well as production costs.
How long do solar panels last?
According to studies, solar panels have a life expectancy of 30 years before we need to discard them or send them for recycling.
After the first 10-12 years of operation, there will be reduction in efficiency by 10%. In the next 20-25 years, the efficiency will reduce by further 10%. After 25 years, the efficiency of solar panels will reduce further by 6% to 8%, making it usable for a total lifespan of 30-40 years with reduced efficiency.
However, there may be other factors that could damage the solar panels before it gets old enough. Apart from that, the rise in efficiencies in newer solar panels due to technological innovations may make the current solar panels obsolete long before they are dysfunctional.
What if we don’t recycle solar panels?
If we discard solar panels directly instead of recycling them, there will be over 60 million tons of wasted panels lying in landfills by 2050. Since the solar cells manufactured today contain toxic substances, it will turn out to be harmful to the environment, defeating our purpose of making solar energy sustainable.
Check out which countries produce the most solar panel waste in this interactive map below:
Map Created by GreenMatch
Future Benefits of Solar Waste Management
In order to reap the benefits of PV recycling, we need to establish a proper recycling infrastructure to manage the ever-increasing numbers of disposed solar panels. This will create new job opportunities as well as economic benefits due to lower manufacturing costs of recycled PV modules.
It has been predicted that recycling solar modules will save £11 billion in recoverable value by the year 2050. This means that we can produce over 2 billion new solar panels without investing a dime in raw materials. Thus, we can produce around 630 GW of energy by reusing the materials that we have used previously!
As the cost of using solar energy continues to drop, more and more households and businesses will prefer to be powered by solar energy instead of traditional grids. This will lead to a greener future, along with sustainable economic and employment opportunities in the solar cell recycling industry.