January 06, 2022 by VCT Group
All human activity generates waste. Technology and energy infrastructure, whether it is “green” or not, creates a waste stream that needs to be responsibly managed. There is no debate to argue against this fundamental truth, and solar is no different.
One of the common objections against solar energy is the end-of-life question surrounding solar panels. Are they good for the environment if we can’t recycle them and they are only destined to pile up in the landfill? How this statement is projected reflects a persistent myth regarding solar – that the panels cannot be recycled. The truth is that they can. The technology to recycle solar panels already exists, and it is being improved through ongoing research.
The recycling industry for solar panels is still in its infancy, however, and may require regulatory changes and financial incentives to keep pace with waste generation. As millions of panels are manufactured each year, there is no question we must develop recycling depots and services in tandem to decarbonization projects that participate in the end-of-life of panels. The ultimate vision is a circular economy for solar, where recovered materials can be reprocessed with solar energy to create new panels.
Solar panels are known to minimally lose efficiency over time. How long they last is an open question. Manufacturers normally offer 25 to 30-year warranties on solar panels, typically guaranteeing that they will still generate more than 80% of their initial capacity after 25 or 30 years of continuous use. These warranties assume a 0.5% to 0.6% loss of performance per year, but their usable lifetimes are projected to be longer.
Solar panels are a remarkably long-lived and robust technology. In 1982 the LEE-TISO testing centre for PV components at the University of Applied Sciences of Southern Switzerland installed a 10kW plant, the world’s first grid-connected system. In 2002 they analyzed the performance of their 20-year-old system of monocrystalline solar panels and the results confirmed manufacturer claims. After 20 years, the initial power output of 37W per panel had only dropped to 32.9W. That’s a yearly decrease of only 0.5%, meaning that the system was still producing 90% of its original capacity. A number of improvements in the technology used in manufacturing solar panels indicates they may actually have an extended lifetime of 40 years, or more.1
Globally, almost all countries still classify solar panels as general waste meaning that they can be disposed of directly in landfills, despite the fact that they may contain hazardous materials. The exception is the European Union. The EU regulates solar panels as e-waste under the Waste from Electrical and Electronic Equipment Directive (WEEE) which bans disposal of them in landfills.2 The EU has effectively drawn a line in the sand to encourage the development of an environmentally responsible lifecycle for PV. As long as panels are considered normal waste, there is little economic incentive to recycle them beyond social responsibility. Reclassifying solar panels as electronic waste is an important first step in moving the industry forward.
As with many things, eventually all solar panels will need to be retired. Ideally, all of them will be recycled. The good news is that there is a way. In tandem with introducing the WEEE Directive, the EU has invested in research into solar panel recycling. The result is the FRELP project – Full Recovery End of Life Photovoltaic. The FRELP process for recycling solar panels has high material recovery rates.
Sasil, an Italian mining technology firm, has been running a pilot facility since 2015, which can process 3,500 metric tons of panels per year, the equivalent of 160,000 solar panels, or 65,000 kW of generation capacity. Now that the technology has been proven, what remains is an expansion of the industry to keep pace with the growth of the solar PV market.
In addition to the FRELP process for bulk materials, research in recovering the various metals in solar panels is ongoing. Leading the way is Meng Tao, a professor at Arizona State University and Fulbright Distinguished Chair in Alternative Energy Technology. Solar cells can contain an assortment of metals, including tin, tellurium, lead, copper, cadmium and silver. Tao’s innovation is called sequential electrowinning and is similar to electroplating run in reverse.
After the glass has been removed from the panels, the solar modules are immersed in a heated nitric acid solution which dissolves the metals. By cooling the leached solution, the tin naturally precipitates out as tin dioxide. By applying different electrical voltages across the remaining solution, the other metals collect on the surface of the electrodes and are recovered. In addition, a secondary process that soaks the remaining silicon in hydrofluoric acid and then sodium hydroxide removes the remaining non-silicon material resulting in a high proportion of solar-grade silicon for reuse. Tao estimates that the metals recovered would be worth $13USD per panel, enough to pay for the recycling.3
In 2016 the International Renewable Energy Association (IRENA) released a comprehensive report, “End-of-life Management Solar PV Panels.” Contained within the report are projections for solar PV waste to be generated by 2050. In 2016 it was calculated that global PV waste streams generated between 43,500-250,000 metric tonnes of material. Keep in mind that the PV cells made from the silicon in 1 tonne of sand produce as much energy during their lifetime as burning 500,000 tonnes of coal in a power plant. This PV waste is equivalent to only 0.1% to 0.6% of the total mass of all the solar panels installed to that date. By 2050, the waste generated is expected to rise to 4% of the total cumulative mass of all panels installed, between 5.5-6 million tons, almost matching the weight of projected new installations at 6.7 million tons per year.4 In the current build-out stage for solar, the low waste numbers reflect the newness of the industry – there simply has not been enough time for PV panels to reach their end-of-life. The projected rise in waste by 2050 is driven by turnover from a mature industry retiring panels from a much larger install base.
The need for solar panels is going to increase exponentially. The scale of addressing the climate challenge is immense. Fortunately, the efficiency of panels has been growing steadily. As panels become more efficient less of them are needed to generate the same output. Currently most commercially available PV panels are around 20-22% efficient in converting sunlight into electricity. Laboratory prototype solar cells have reached efficiencies as high as 39% for non-concentrated sunlight, and 47% when the sunlight is concentrated.5 Clearly there is still significant room for improvement in commercial solar cells.
It is important to note that increased efficiency may create financial incentives to replace panels earlier than their warrantied end-of-life, generating more waste than projected from using the panels for their full lifetime. It is important that solar panels are kept in service for as long as possible to maximize their utility and reduce unnecessary waste. If panels are replaced early, they should be reused.
At the end of their warrantied lifetime solar panels still retain most of their performance. At this point they may be replaced, but that does not mean they are waste. With several years of usable lifetime remaining, they can be reused for less energy-intensive projects and remain productive. The best approach is to maintain solar systems diligently to maximize their lifetime, and then to divert replaced panels for secondary use.
Creating secondary markets is a promising strategy for reducing the amount of waste in the short term. A panel that begins its life in a high-efficiency, utility-scale solar farm can have a second life in a home installation, an off-grid system, or power generation in a developing economy. In all cases, care will need to be taken to avoid dumping panels without first ensuring that their end-of-life will be addressed responsibly.
Solar power is a young industry. Most of the current solar capacity has been installed within the past 10 years. It will take time for the capacity of the recycling industry to catch up. Fortunately, the long life of solar panels provides a window of opportunity for innovation and growth in the market.
There is value in PV panel waste. The International Renewable Energy Agency (IRENA) projects that by 2030 the recoverable value in raw materials will reach $450 million USD. By 2050 the value creation from raw material recovery is projected to be $15 billion USD.6 There is a clear economic opportunity for the creation of new industries and employment. At this early stage, further government-funded research and development, and subsidies, may be required to kickstart the recycling industry.
The industry currently faces a chicken and egg problem. How does the recycling industry grow when incentives are lacking, and the current waste stream is too small to take advantage of economies of scale?
The first step is to follow Europe’s lead and reclassify PV panels as e-waste and pass legislation creating an Extended Producer Responsibility (EPR) for their end-of-life management. Until PV panels are treated globally as e-waste there will remain no incentive to recycle them, simply because disposal is the cheapest option.
Placing responsibility with the manufacturers has the added benefit of creating a strong economic incentive for improving product designs to make them easier to recycle; and to incorporate recovered materials in the production of new panels.
Canada does not currently have the capacity to efficiently recycle solar panels, or legislation governing their end-of-life as e-waste. Canada relies on shipping used panels out of the country for processing. A major player in the industry is Dynamic Lifecycle Innovations, with locations in four provinces. The company collects panels and ships them to U.S. recycling facilities. Another is First Solar, both a manufacturer and recycler, who offers a pre-funded takeback program for their modules. With facilities in the U.S., Germany and Malaysia, First Solar is a pioneer in implementing a circular approach to their product. Although their current strategy is centralized, they are investigating the potential for mobile, on-site recycling to avoid the energy cost of shipping waste panels.7
One roadblock to panel recycling has been the limited accessibility of vendor information. SolarRecycle.org has launched an initiative to collect information on solar panel recycling companies and make it available. While it is currently limited to vendors located in the US, it is a visible demonstration of the industry’s growth. The market availability of panel recycling continues to grow.
To date, our need for panel recycling has been low. On large-scale installations we typically only see accidental losses of 1 or 2 panels per project during construction. The newness of our projects means that anticipated mass retirement of panels is still decades away. Our biggest retirement of panels has been related to damage from adverse weather events.
Our approach to broken panels has been two-fold: In the short term we have been storing panels that require recycling to divert them from the landfill while we wait for the industry to expand its Canadian capacity. Secondly, we have been offering panels with salvageable solar modules to hobbyists in the community for reuse.
We are following the development of recycling options closely and are looking forward to a future when solar achieves a truly circular economy.
The criticism of the solar industry for its lack of recycling is untrue at best; and at worst, it is a damaging disincentive to adopt renewables and electrify our economy. Globally, progress is being made to expand recycling capacity and the technology is an active area of research. While the recycling of solar panels has not yet kept pace with growth, there is a realistic window of opportunity for the industry to catch up. In the meantime, it is important to focus on the clear and present need to decarbonize as quickly as possible and continue to increase our renewable infrastructure.
New regulatory frameworks, like those in the EU, will require manufacturers to take full responsibility for the life cycle of their products creating the incentive to expand recycling capacity.
As the cost of new solar panels continues to drop, and the availability of key minerals becomes more scarce, the recovered materials will become an increasingly valuable resource. Recycling will become economically competitive instead of an added bottom-line expense.
At VCT Group, we are committed to the expansion of distributed solar power as a key pillar in achieving net-zero by 2050. Our rust-free, all-aluminum products are designed to be long-lasting and fully recyclable. We recognize that our industry can do better and are designing our systems with intention. We believe that solar is vital for our future. Solar is for everyone.