The rapid expansion of solar power could create a massive waste challenge in the coming decades, with global photovoltaic (PV) panel waste projected to reach between 297 million and 402 million tonnes by 2060. Researchers, however say recycling the retired panels could turn this growing waste stream into an economic opportunity worth nearly $1 trillion.
A study published in the journal Nature examined how countries could manage the expected surge in discarded solar panels while recovering valuable materials and reducing environmental impacts.
Most solar panels have an operational life of around 25 to 30 years. As installations expanded rapidly over the past two decades, growing numbers of panels are now approaching the end of their useful lives.
The study estimates that after 2040, middle-income countries, particularly China, could become major sources of retired PV panels as early solar installations are decommissioned.
At present, specialised recycling capacity remains limited in many countries. Some discarded panels are sent to landfills or stored because appropriate recycling facilities and disposal regulations are not widely available.
Solar panels contain materials that can be recovered and reused, including silicon, silver, copper and tellurium. Some panels can also contain potentially hazardous substances such as lead and cadmium.
Researchers examined 1,708 recycling scenarios across 32 regions using a computer model that considered factors including recycling infrastructure, material prices, international trade and government subsidies.
The analysis found that recycling systems tailored to regional conditions, combined with international cooperation, could deliver the greatest economic benefits.
Recovering valuable materials could also reduce the need for new mining and processing, potentially preventing billions of tonnes of carbon dioxide equivalent emissions over the coming decades.
Current recycling systems recover only part of the value
Many existing recycling facilities treat solar panels similarly to other electronic waste. They commonly recover materials such as aluminium frames and glass but recover relatively little of the silicon and precious metals contained within solar cells.
More advanced technologies can recover high purity silicon and silver, but such facilities require substantial investment.
Researchers therefore emphasise the need to build specialised recycling infrastructure before the volume of retired panels increases sharply.
Recycling could strengthen critical material supplies
Solar panel recycling could also reduce pressure on supplies of raw materials needed for the clean energy transition.
Mining materials such as silver, silicon and tellurium requires energy and can create environmental impacts. Recovering these materials from retired panels could reduce dependence on newly extracted resources.
Recycling could also improve supply chain security. Countries with limited domestic reserves of critical materials could recover resources from their own retired solar panels, reducing reliance on imports and exposure to international supply disruptions.
The researchers also warn that the financial gains from solar panel recycling may not be distributed equally.
If old panels are transported to countries with cheaper or more advanced recycling infrastructure, developing regions could potentially bear environmental risks without receiving a proportional share of the economic benefits.
The study therefore proposes a phased subsidy model under which governments initially support recycling facilities and gradually reduce assistance as the industry becomes commercially viable.
According to the researchers, such an approach could improve the distribution of economic benefits without the high cost of permanent subsidies.
Need for a circular solar economy
The study highlights the importance of planning for solar panels throughout their entire life cycle rather than focusing only on their electricity generating phase.
As the global solar industry expands, researchers say countries will need to invest in recycling capacity, improve recovery technologies and establish policies that encourage the reuse of materials.
With adequate infrastructure and international cooperation, discarded solar panels could become a significant source of raw materials rather than a growing environmental burden.
The challenge, researchers argue, is to build the recycling system before the world’s solar waste problem reaches its peak.