PV recycling

Solar panels waiting to be recycled

What do you do when a solar panel comes to the end of its useful life? Moreover, what do you do with billions of them? Eva Matthews investigates.

From its infancy in the 1980s, solar as a source of renewable energy has finally become mainstream. In Australia, installed solar capacity has grown from 0.13 GW in 2010 to 6.2 GW as at mid-2017—a 4500% increase. Globally, in the same timeframe, capacity has grown from 50 GW to 305 GW. Fantastic!

Assuming that today’s panels are typically 270 W to 300 W, this equates to a current global total of at least 1.1 billion panels—and given the early panels were just 60 W, this number is likely to be higher in reality. That’s a mind-boggling figure! And it’s only going to get bigger, with global installed capacity projected to reach 4500 GW by 2050.

At some point (let’s assume 25 years, the standard warranty period), all of these panels will come to the end of their useful lives … and then what? Given a standard panel weight of 18 kg, that’s roughly 20 million tonnes of potential waste to manage.

Panels may also be retired before the 25 years is up. Leaps in technology may lead to systems being upgraded early and a significant number of panels (roughly 10%) fail early due to damage during manufacture, transport or handling.

Trash and treasure
Unless properly managed, all this potential waste becomes a monumental problem. To date, unusable solar panels have often ended up in landfill, along with many thousands of tonnes of electronic waste (e-waste) despite programs to divert the waste for recycling.

PV panels contain small amounts of hazardous substances. These will only leach out if the panels are broken up—unfortunately, this is pretty much guaranteed to happen when they are deposited in landfill. In small amounts, the toxicity may be negligible, but when you’re talking millions of tonnes of panels, the danger of contamination is a significant concern. Silver, tin and lead (particularly in older panels) are the hazardous components of mono- and polycrystalline silicon panels (estimated at 50% to 60% of the market); indium, gallium, selenium, cadmium, tellurium and also lead are found in thin-film panels.

Currently 85% to 95% of a panel can be reclaimed and recycled. Some damaged or early-fail panels can be repaired and resold on the secondhand market or to developing countries at reduced prices, allowing access to solar technology to those who might otherwise not be able to afford it. Glass, copper, lead, aluminium and the hazardous semiconductor materials can be reclaimed through a mix of mechanical and chemical processes that have relatively low environmental impact, and either melted down for recycling or sold on as raw materials to be used in the creation of new solar panels and other electronics, reducing the embodied energy going into their manufacture.

Not only does the reclaiming/recycling approach make environmental sense, it’s worth big money. The most recent reports place the value of the global yield of recovered raw materials from solar panels at US$450 m by 2030, and in excess of US$15 b by 2050.

Thankfully, as a result, a PV recycling industry has emerged.

Read the full article in ReNew 142.

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