Solar Is Here to Stay. Is the Same True for Solar Panel Waste?

Solar is crucial to the green energy transition. But what happens to all those solar panels when they reach the end of their lifespan?

In most cases, the lack of recycling infrastructure means they are stripped of any valuable materials before being dumped in landfills, where their toxic components seep into the soil, threatening local ecosystems and communities.

This is especially true in developing countries, where solar adoption is rising rapidly. A new Nature paper, co-authored by HKU Professor Kuishuang Feng, has mapped the scale of this problem and identified a possible solution: temporary recycling subsidies to help developing nations build out the infrastructure needed to recycle solar panels.

Dumping grounds

Solar technology has advanced quickly in recent years, especially in developing countries, as it offers an appealing alternative to unreliable or expensive fossil fuel-based power grids.

All those solar panels will one day need to be recycled, however, and the study revealed a dramatic shift in projected photovoltaic waste. Prior to 2040, high-income regions dominate the waste stream; by 2060, however, emerging economies will take the lead, with China alone accounting for between 36% and 40% of the global total, Professor Feng says.

Managing that surge will require significant investment in recycling in many of the regions that can least afford it. In turn, this may exacerbate regional inequalities, as the environmental costs of photovoltaics are outsourced to the regions least able to mitigate them, while green energy’s benefits accrue to the developed world.

Costs and benefits

To mitigate these inequalities, the study tested five subsidy designs, from continuous and declining subsidies to no subsidies.

It found that declining-subsidy schemes, which phase out fiscal support as recycling becomes self-sustaining, are the most cost-effective, requiring less spending than continuous subsidy schemes while actually delivering greater improvements in inter-regional equity.

“You can’t subsidise forever,” says Professor Feng, an expert in green supply chains at the University’s Department of Geography. “You need to work systematically, building capacity before phasing them out.”

The study is just a start, he notes, adding that fixing the problem will require international cooperation, including the formation of a global market for waste recycling.

“Particularly in developing countries, recycling is unaffordable,” he says. “We need a long-term design approach. Developed countries don’t want to recycle at home, but they need to take responsibility for panels getting recycled elsewhere.”