Solar power is expanding rapidly around the world. But solar panels have a limited lifespan, and the large number of panels now being installed will eventually have to be taken out of use.
An international group of researchers has investigated what this means for future waste volumes and how different ways of recycling solar panels affect the economy, climate and distribution of benefits between regions.
Their calculations suggest that cumulative global photovoltaic (PV) waste could amount to between 297 and 402 million tonnes by 2060. Annual retirements are projected to rise from around half a million tonnes in 2030 to more than 19 million tonnes in 2060.
鈥淭he urgency lies less in the waste itself than in the infrastructure. Recycling plants and regulations take a decade or more to establish, and we found that recycling will not break even until roughly 2035 to 2040. That gap is the window we are in now,鈥� says John Laurence Esguerra, Assistant Professor at Link枚ping University and one of the authors of the study.
Valuable materials can be recovered
End-of-life solar panels contain materials such as silicon, glass, silver, aluminium and copper. Recovering them reduces the need to produce new raw materials.
Today, however, recycling capacity differs greatly around the world. Panels may be sent to landfill or processed mainly to recover glass and aluminium, while more valuable materials such as silver and high-purity silicon can be lost. Poorly managed waste can also pose environmental risks.
The researchers estimate that, under the recycling scenarios with the greatest overall benefits, greenhouse gas emissions could be reduced by up to 3.32 billion tonnes of carbon dioxide equivalent cumulatively by 2060. Over the same period, the cumulative net economic benefits could reach between USD 529 and 935 billion.
Teiksma Buseva
鈥淩ecovered silicon, silver, aluminium and copper substitute for energy-intensive virgin production. That substitution is what generates the emission savings, and rising prices for those same materials are what eventually make recycling pay,鈥� says John Laurence Esguerra.
Efficiency can increase inequality
But the study identifies a dilemma. Recycling solar panels where the waste arises distributes the benefits relatively evenly, but many regions lack sufficient volumes of waste or the technology needed for efficient recycling.
Allowing waste to be transported to regions with established recycling industries increases the overall benefits through economies of scale and more advanced technologies. But it also concentrates those benefits in fewer regions.
The researchers found that local recycling generates only around 69鈥�78 per cent of the benefits achieved when trade in PV waste is allowed.
鈥淭he highest-benefit configuration was also among the most unequal. That is the central tension in the study: efficiency and equity do not automatically go together,鈥� says John Laurence Esguerra.
The design of subsidies matters
The researchers also investigated whether subsidies could reduce these differences. One finding was that linking subsidies to a high carbon price could actually increase inequality, as higher-income regions with established carbon markets and favourable conditions for recycling receive more support.
A declining subsidy performed better in the model. This provides support while the recycling industry is developing and withdraws that support gradually as recycling becomes profitable. The study found that this approach could improve equality at a fraction of the cost of continuous subsidies.
鈥淩ecycling solar panels will be worth doing, both economically and for the climate, but it will not become fair on its own. The decade before it turns profitable is when policy has to do the work, and how that support is designed decides whether the benefits reach everyone or only a few regions,鈥� says John Laurence Esguerra.
