The global boom in solar power is helping countries move toward cleaner energy, but it is also creating a growing waste problem.
New research suggests that hundreds of millions of tonnes of old solar panels could be discarded worldwide over the coming decades.
The good news is that this waste could also become an enormous economic opportunity.
Researchers estimate that properly recycling retired solar panels could generate close to $1 trillion in economic benefits by 2060.
The international study, involving researchers from China, Australia and Sweden, estimates that between 297 million and 402 million tonnes of photovoltaic, or PV, waste could accumulate globally by 2060.
Middle-income regions, particularly China, are expected to become major sources of discarded panels after 2040.
Professor Jian Zuo from Adelaide University, a co-author of the study, said governments and the solar industry need to think about the entire life of solar panels, including what happens when they are no longer useful.
Solar panels contain a range of valuable materials that can be recovered and reused, including silicon, silver, copper and tellurium. They can also contain potentially harmful metals such as lead and cadmium, making proper disposal important for protecting the environment.
To identify the best ways to manage this growing waste stream, the researchers examined 1,708 recycling scenarios across 32 regions. Their model considered factors including recycling technology, material prices, international trade and government subsidies.
The results suggest that using recycling methods suited to individual regions, while also allowing some waste to be processed in countries with more advanced facilities, could provide the greatest overall benefits. Such an approach could produce hundreds of billions of dollars in net economic gains while preventing billions of tonnes of greenhouse gas emissions.
However, the researchers also identified a major problem. Sending waste to countries with cheaper and more advanced recycling systems may be efficient, but it could leave poorer countries with very little of the financial benefit.
Even if recycling technology becomes more widely available, low-income regions could receive only a small share of the global economic gains. The researchers therefore argue that recycling policies should consider fairness as well as cost and efficiency.
One possible solution is a declining subsidy system. Governments could initially provide financial support for solar panel recycling and gradually reduce those subsidies as the industry becomes profitable. The study suggests this could help distribute economic benefits more fairly without the high cost of permanent subsidies.
The value of recycling could also rise as prices increase for recovered materials such as silver, aluminum and silicon. At the same time, advances in recycling technology are expected to bring processing costs down.
The researchers say countries have an opportunity to act before solar waste reaches its peak. By investing in recycling facilities, sharing technology and treating old panels as valuable resources rather than rubbish, the clean-energy transition could become more sustainable—and potentially much more profitable.
