By 2060, between 297 and 402 million tons of end‑of‑life solar panels could accumulate worldwide. At present, recycling them is in most cases more expensive than the value of the materials recovered, but by around 2035-2040 the situation could change. According to calculations by an international group of scientists, by that time the value of silver, silicon, copper, aluminum, and other materials recoverable from old modules will begin to cover recycling costs. By 2060, the cumulative net advantage of the most effective industry setup could be between $529 billion and $936 billion, helping to avert up to 3.32 billion tons of CO₂ equivalent emissions.


This is the conclusion of researchers from Shandong University and Huazhong University of Science and Technology in China, the University of Adelaide in Australia, the University of Hong Kong, Taiyuan University of Technology, and Linköping University in Sweden. The scientists modelled the development of solar panel recycling in 32 regions of the world and examined 1,708 possible scenarios. The calculations took into account the rate of solar power plant construction, module service life, prices of the materials they contain, the development of recycling technologies, and the possibility of transporting end‑of‑life panels between countries.

The scale of the problem will grow rapidly as solar power plants built during the current renewable energy boom reach the end of their service life. Solar modules last on average 25–30 years, after which they must be decommissioned. According to the scientists’ calculations, the annual volume of such waste will increase from about 0.5 million tons in 2030 to more than 19 million tons in 2060. Its geography will also change. Until 2040, more than half of spent panels will come from high‑income countries, but thereafter an increasing share will come from developing economies. By 2060, China alone could accumulate between 112.8 and 160.5 million tons of old modules, precisely about 36‑40% of the global total. India would account for another 26.8‑35.2 million tons.


The main value of old panels lies in the raw materials they contain. In addition to glass and aluminum, modules can be recycled to recover copper, silicon, and small amounts of silver. The latter two materials are particularly important: their extraction is more complex, but they significantly increase the economic attractiveness of recycling. Currently, however, costs remain too high. In 2020, the materials recoverable from one ton of old panels were worth between $132 and $304, while recycling the same ton cost $342–$2,550 depending on the technology. By 2040, the value of recoverable raw materials could reach about $457 per ton, while recycling costs could fall to $56.


The scientists compared three main recycling methods: mechanical, thermal, and chemical. Mechanical methods mainly allow the module to be disassembled and shredded, after which its components are separated. More complex thermal and chemical processes can recover more valuable materials, although they require additional costs and energy. The most profitable scenario in the calculations was one with wider adoption of advanced thermal technologies. Even without international waste transport, this could provide about $671 billion in net economic benefits by 2060 and prevent about 2.44 billion tons of CO₂‑equivalent emissions.


The system becomes even more efficient if old panels are allowed to be transported between regions. A country with a small amount of waste does not necessarily need to build its own expensive plant: modules can be sent to places where large facilities already operate and recycling is cheaper. For example, panels from developing regions could be sent to processing plants in China. In the most favorable scenarios, such an approach increases the total net benefit to $936 billion and avoids 3.32 billion tons of CO₂‑equivalent emissions.


However, for individual countries, such a scheme may not be equally beneficial. The main profit from extracting and selling materials remains where the recycling plants are located. As a result, countries that already have the technology and industrial base gain an additional advantage, while less affluent countries effectively export, along with the old panels, the potential revenue from their recycling. According to the scientists’ calculations, international waste trade without additional measures could widen the gap in economic benefits between regions.


One way to address this problem, the researchers suggest, is temporary state support. The most effective scheme was found to be declining subsidies: the state helps launch recycling when it is still unprofitable, then gradually reduces payments as the technology becomes cheaper. Permanent subsidies are considerably more expensive – according to the authors’ estimates, the required expenditure could be roughly 9.5 times higher. Declining support also helps reduce the gap in recycling revenue between regions from $1,147 to $1,061 per ton.


At the same time, support through the carbon market could produce the opposite result. When carbon prices are high, more funding goes to regions that already use more advanced, low‑carbon recycling technologies. As a result, the advantage of wealthy countries is only reinforced, and the gap in economic benefits could widen by a further 4%.

Source: Global Energy