How to tackle the looming challenge of solar PV panel recycling

The boom in installation of solar photovoltaic (PV) panels in recent decades has helped nations tackle their carbon emissions. But the technology has a useful lifespan of about 25–30 years, which means a rapidly growing number of PV panels will soon need to be disposed of (1). And while the environmental impact of their construction has received much attention, what happens at the end of their life cycle has garnered less scrutiny. At present, only about 10% of PV panels are recycled, with the majority being dumped, burned, or buried.

The global cumulative amount of PV panel waste is expected to reach 1.7 million tons by the early 2030s. Only with major strides in PV recycling can we avoid major pollution problems and health risks. Image credit: Shutterstock/Bilanol.

This trend is not sustainable and, if not addressed, will lead to increases in pollution, elevated risks to human health, and further shortages of the key materials needed to make the next generation of solar energy equipment. As we outline here, scientists, companies, and policymakers must set out mechanisms, regulations, and technical pathways to encourage more solar PV panel recycling and avoid this potential crisis.

Growing Problem

Cumulative global installed PV capacity now exceeds 2 terawatts. With expected growth of 25%, that capacity could reach 75 terawatts of installed PV by 2050 (2). Eventually, each of those panels will need to be decommissioned, and the amount of waste will quickly swell to levels that will swamp recycling facilities.

Projections for global PV end of life (EOL) management by the International Renewable Energy Agency (IRENA) indicate that under a regular loss scenario, the global cumulative amount of PV panel waste is expected to reach 1.7 million tons by the early 2030s. By the 2050s, the PV waste level could reach 60 million tons (Fig. 1 A and B) (3). And that could be an underestimation. It’s possible that degraded panels will be replaced sooner than expected. Under this “early loss scenario,” the PV waste surge will come sooner. By the early 2030s, the global cumulative amount of PV waste is expected to reach 8 million tons, and by the 2050s, the PV waste level could reach a staggering 78 million tons.

Fig. 1.

The future of PV decommissioning. Under regular loss and early loss scenarios, the figure indicates (A) modeled results of estimated cumulative waste volumes of EOL PV panels in major countries by 2030 and 2050; (B) global PV panel waste projections, 2016–2050; and (C) China PV panel waste projections in 2030, 2040, and 2050 by the China ECOPV Alliance. Image credit: Siyou Xia, plotted from data in refs. 3 and 4.

China is the world’s largest producer of solar PVs, and its cumulative PV panel waste could reach almost 13.5 million to 19.9 million tons by 2050 (Fig. 1A), according to IRENA. By then, China will have to deal with the greatest volume of decommissioned PV modules in the world (3). However, separate projections from an industry body called the PV Committee of China Green Supply Chain Alliance (China ECOPV Alliance) estimate that the cumulative amount of PV waste in China will reach 1 million, 12 million, and 55 million tons of PV waste by 2030, 2040, and 2050, respectively, under the regular-loss scenario. For the early loss scenario, China is expected to reach 4 million, 23 million, and 66 million tons, respectively (4). This is significantly higher than the data released by the IRENA (Fig. 1C). These figures are provisional, and many uncertainties remain, but it’s clear that the world, and China in particular, must gear up to manage massive amounts of PV waste in a relatively short period of time.

PV panels contain potentially reusable resources, including glass, aluminum, plastic, silicon, copper, and silver. Unfortunately, these are difficult to extract from used panels, which consist of several layers bonded together for durability. This makes separation awkward for existing recycling technologies, which chiefly entail shredding and thermal processing. And, if not handled properly, discarded panels can leak toxic heavy metals, including lead and cadmium, into soil and water.

There are economic challenges, too. Recycling requires dismantling, collection, transport, and processing. Different panel designs need specific approaches—materials used in thin film modules differ from those in crystalline silicon panels—and this hinders the development of common standards and industrial processes. Many panel manufacturers are also reluctant to adapt their systems to accommodate supply of recycled components, instead often opting for virgin materials (5). Put simply, if the costs of recycling panels are too high, there’s no financial incentive to do so.

Rules and Regulations

The best way to address these technical and economic obstacles is with well-constructed and evidence-based policies to encourage and, in some cases, mandate PV panel recycling. At present, there are no consistent recycling standards and norms globally. That means an inefficient recycling process and slower development of industrial recycling capacity.

Many regions have no regulations on PV disposal, including how to manage the mixture of PV panels in smelting or to control the emissions produced. Such policies are typically in place for the recycling of many other solid wastes. And there are few subsidies or other incentives to encourage PV recycling. There’s also a lack of awareness among consumers and businesses and a lack of industrial facilities that can dispose of panels sustainably and responsibly. As a result, most PV panels are casually discarded—sent to a landfill or piled up in open lots or fields.

The situation in Europe demonstrates both opportunities and challenges. In 2012, the European Union (EU) introduced rules on the disposal of electronic waste, which covers PV panels. The directive makes panel manufacturers responsible for recycling and sets phased targets to increase uptake. Converted into national laws that include registration fees, enforcement measures, and fines, the regulations have resulted in some 20 commercial PV recycling plants in the EU. Even so, their combined 2023 capacity of 40,000 tons is less than a third of the total panel waste produced now and clearly won’t be able to handle the projected increase in the coming years.

These problems are well understood by industry analysts, and experts, including IRENA, have called for rapid action to boost sustainable PV waste management. Yet, we are not on track to handle the coming surge in obsolete and redundant panels. That’s especially acute given the large number of PV facilities that are funded directly or indirectly by nation states. Commercial operators generally set aside funds to cover EOL decommissioning, but countries will need to find the money from public budgets that are already stretched thin.

Finding Solutions

The multiple challenges of managing large-scale PV wastes demand a proactive approach; the costs of being underprepared or unprepared far outweigh those of early preparation. We must anticipate the upcoming challenges, as well as new risks, and prepare for harms before they materialize. Sustainable strategies will require new policies.

Retrofit options and decommissioning methods should be built into the initial design and planning stage of PV panels, not as an afterthought. Knowing more detailed information in advance, such as when and where a solar PV facility closure will take place, as well as the scales and growth trend of PV wastes, will allow for long-term budgeting by the companies and governments that track decommissioning costs and environmental impacts. Doing so will also help steer local environmental remediation of decommissioned facilities. Clear and realistic expectations about when PV retirements will occur can help supporting industries plan infrastructure and effective supervision of PV wastes. Going forward, decommissioning planning must consider the whole system, including PV waste generation, collection, transport, recycling, and treatment, as well as recovered resource use and disposal of remains.

Effective decommissioning planning should be participatory, inclusive, and government-supported, enrolling stakeholders including researchers, citizen scientists, the general public, and, where appropriate, Indigenous people with local knowledge of the environs.

Effective decommissioning planning should be participatory, inclusive, and government-supported, enrolling stakeholders including researchers, citizen scientists, the general public, and, where appropriate, Indigenous people with local knowledge of the environs (6). Doing so can help address the challenge of low social participation. Some PV users don’t realize that PV panels need to be professionally recycled, and hence may discard them or mix them with household waste.

Governments, companies, and investors can support the construction of recycling infrastructure. Researchers can work on innovative and more efficient ways to extract the useful raw materials from spent panels, such as chemical dissolution and pyrolytic lamination techniques—approaches that are still at the laboratory stage.

Regulators and environmental organizations should test and measure the viability of solutions and help implement and promote actions to adopt them. Governments should pursue mandatory and more rigorous decommissioning risk assessments with enforceable consequences, and mitigation standards that are commensurate with the hazards of PV waste will also be needed.

The most promising solution is recycling that allows raw materials, such as silver, copper, and aluminum, to be extracted from decommissioned modules and returned into the supply chain to make new solar panels (7). Closed-loop supply chains based on a circular economy—combined with advancements in waste separation, materials science, waste processing, and advanced recycling—would enable the sustainable reuse of PV modules (8). According to the National Renewable Energy Laboratory (NREL), by 2035, recycled materials from retired PV panels could provide over 50% of the silver we need for new PV panels, as well as over 30% of the aluminum, silicon, and glass (9). In the longer term, by 2050, the cumulative technical potential of recoverable materials in old solar modules is expected to be worth $15 billion (3).

There have been some promising recycling trends of late. For example, a salt-etching approach can recover more than 99.0% of silver and more than 98.0% of silicon from EOL panels (10). Copper, lead, tin, and aluminum can also be recovered through a combined oxidation, alkaline leaching, and electrodeposition (10). And there’s a need to invest in waste prevention and capacity-building, such as providing subsidies, designing for adaptability and longevity, and by scaling up recycling infrastructure. These should be coordinated with better design of PV waste recycling systems (7, 11).

One effective practice that could be applied to the management of PV waste is Extended Producer Responsibility (EPR), which makes producers responsible for the entire lifespan of the PV material, including the EOL. EPR, initiated through government policies, encourages durability, extended PV product lifetimes, and designs that allow for easy reuse, repair, or recycling of materials. In principle, this could help drive more sustainable design, as well as options for reuse and repair (8).

By incentivizing EPR with tax breaks and/or manufacturer subsidies, governments can integrate disposal or reuse into waste management practices, encourage trade-ins between PV owners and manufacturers, and establish a circular economy of PV panels (12). In general, manufacturers can extend the life cycle of old PV panels through technological innovation, or they can recycle valuable materials from old PV panels to make new panels. Both approaches are effective measures to address the challenges of PV decommissioning.

An example of a successful EPR program is the PV Cycle in Europe for PVs. The program has helped to create a new market for used PVs, helping to recycle more than 60,000 tons of used crystalline silicon PV modules (13). It’s still nascent and will need to be expanded, but it’s a start.

Role of Research

PV innovation starts with rigorous research and development, and scientists have started to explore new materials and designs to enhance module sustainability and extend the “cradle-to-grave” life cycle of PV materials. Already, there are some innovations that could prove helpful. For example, foldable silicon wafers and flexible solar panels will enhance the durability and life-cycle sustainability of PV panels, helping to reduce the scale of PV waste and ease recycling pressures (14). Researchers must design PV materials that are easy to recycle, as well as recycling processes that facilitate sustainable closed-loop recycling (15).

Emerging technologies hold considerable promise to improve decommissioning efficiency (16). Artificial intelligence (AI) combined with PV waste-management platforms has the potential to make PV waste recycling easier and more profitable. For instance, using AI alongside robots could help in disassembling, separating, grinding, and sorting decommissioned PV modules, increasing the automation and intelligence of waste management activities. Such AI systems could also potentially help plan ahead for decommissioning by analyzing historical data to predict the lifespan of components and help establish a database to track the full life cycle of modules.

Meanwhile, the integration of machine learning algorithms with physics-based modeling and experimental automation can effectively identify, predict, and optimize PV material performances during the design and synthesis phase.

To find better ways to fabricate more sustainable panels and to recycle, researchers will have to combine emerging technologies, PV waste recycling, and innovative research results in disciplines ranging from materials science to sustainability science to computer science. This necessitates policies that promote interdisciplinary research and support collaboration between firms, university research, and other relevant institutions such as policy think tanks in PV recycling innovation. We also need common methods to establish PV waste databases to include information on module installations, lifetime forecasts, and EOL times, as well as a dynamic assessment of recycling needs.

Finally, there is a clear need for broad global cooperation among researchers, industry, and government to develop and share technologies and expertise for recyclable PV waste. Ideally, countries that lead in PV waste management will share their technologies and expertise with those with less capacity. It’s in the interest of all nations using PV; sharing expertise and resources allows for the development of recycling systems in developing countries, mitigates global environmental risks, leads to more robust supply chains, and reduces the cost of raw materials. Together, the countries can lay the foundation for addressing the looming global wave of decommissioned PV panels.