The Downside of Solar Energy - Recycling?

Solar Energy / Related Environmental Issues / Environmental Impact

Mulvaney and Bazilian  opine that as renewable energy expands, used photovoltaic panels are creating a growing waste problem—but recycling could be the answer. The solar economy continues its dramatic growth, with over a half-terawatt already installed around the world generating clean electricity. But what happens to photovoltaic (PV) modules at the end of their useful life? With lifespans measured in decades, PV-waste disposal may seem to be an issue for the distant future. Yet, the industry ships millions of tons every year, and that number will continue to rise as the industry grows. Total e-waste—including computers, televisions, and mobile phones—is around 45 million metric tons annually (more).

By comparison, PV-waste in 2050 will be twice that figure. Motivated by concerns about exposure to toxic materials, increased disposal costs and overcapacity at landfills managed by underfunded local governments, researchers are exploring global solar waste management solutions based on concepts like the circular economy.

At the same time, demand for everything from sand to rare and precious metals continues to rise. While supplying only about 1 percent of global electricity, photovoltaics already relies on 40 percent of the global tellurium supply, 15 percent of the silver supply, a large portion of semiconductor quality quartz supply, and smaller but important segments of the indium, zinc, tin, and gallium supplies. Closing the loop on these metals and embracing circular economy concepts will be critical to the industry’s future.

Market signals are essential to attracting investment in recycling infrastructure. SolarWorld in 2008 experimented with recycling technologies when polysilicon spot prices spiked in the 2000s. The recycled silicon became a hedge on the price for their supply. They demonstrated that recycled silicon resulted in 50 percent reduction in energy needed to make an entire PV module just by using 100 percent recycled silicon feedstock. But this pilot facility never scaled to the automated PV recycling facility they planned and was closed early as the company struggled to compete with emerging PV manufacturers.

The National Standards International/American National Standards Institute has a sustainability leadership standard that rewards companies participating in take-back and collection schemes that are not funded by customers. First Solar has recycling facilities capable of recovering 95 percent of the semiconductor materials and nearly all of its tellurium. This helps them meet regulatory requirements around cadmium content and guarantees to keep it out of landfill, while acting as a hedge to investors against tellurium supplies and price volatility.

All of these trends point to a need for greener product design and supply chain responsibility to ensure sustainability. Solar energy is critical to addressing both climate change and energy poverty. Embracing a circular economy approach to PV-waste and materials recovery is urgently needed to support those roles.

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