What Can We Do With Old Solar Panels?—Renewable Energy and Recycling, Part 1

I have a Google alert for the phrase “Material Value,” the title of my 2019 book. It recently turned up an article called “Can We Recycle Spent Renewable Energy Infrastructure?” Spent infrastructure is stuff in the built environment that is no longer useful in its original form.

That might come from the demolition of old buildings, roads, or bridges. It also might come from structures and components built to generate renewable energy.

Have you thought about what happens to solar panels and wind turbines when they have served their purpose? What about lithium-ion batteries whose capacity has diminished? Unfortunately, they often end up in landfills.

Could they experience a different fate? Are there ways to extend their lifetime or repurpose these items so they can be used in a different way? Could the components and materials within them be recycled?

I examine these ideas in a three-part blog series. The first blog in the series considers solar panels.

Lifespan extends beyond the warranty

Solar panels installed in the 1990s and early 2000s are approaching the end of their 25-year warranty period. Millions more will reach this point in the coming years. What is being done, and what more can we do to extend the usefulness of these panels and keep them out of landfills?

First of all, just because the warranty has expired doesn’t mean that the panels are no longer good. Vehicles come with 3-year or 5-year warranties beyond which the manufacturer will no longer pay to replace parts. With proper maintenance, the cars will still run for many years. The same is true for household appliances and for solar panels.

Panels degrade, on average, about 0.5 percent per year. That means that panels that are 25 years old still produce nearly 90 percent of their original energy output. Actual degradation varies depending on the quality of the solar panels, local weather conditions (extreme heat or lots of snow are detrimental), and how well they are maintained. Maintenance and cleaning can minimize damage like cracking or scratches.

The upshot? Solar panels can last longer than 25 years. Residents and businesses with solar installations that are providing enough energy to meet their needs have no reason to replace them. Still, some older panels are starting to be discarded when owners upgrade to new panels.

What about recycling?

Three things have to line up for something to be recyclable: science, technology, and economics. Let’s look at each of these.

Science

Can the product be separated into distinct materials, and can those materials be ground up, melted, and processed into usable recycled content? For solar panels, the answer is a qualified yes. It is possible to recycle glass, which makes up most of the weight of a solar panel. Glass from panels is already being recycled, though not at rates as high as they could be.

Aluminum frames are completely recyclable if separated from the panel. Silicon is also recyclable, although separating it is more challenging. Many panels also contain silver. Even plastic parts could technically be recycled.

Technology

Are there systems in place to disassemble the products and sort the individual materials so they can get to a processing plant? The challenge here is disassembly.

Aluminum frames are not hard to separate. Recyclers can also strip copper wiring from the back of the panel. At that point, it is easiest to shred the panel and sell the resulting mix as crushed glass. The crushed glass might end up as a cover layer in a landfill.

Some startups are working on technology that can extract usable metals from the panels themselves and possibly silicon as well. Silicon is a very energy-intensive material to produce from silica (sand), so it would be great to be able to recycle it.

Economics

Is there a market to buy the recycled materials at a price that is high enough to justify the transportation and processing costs? This is almost always the sticking point.

Even when manufacturers want to do the right thing, if it costs less to send something to a landfill than to recycle it, it goes to the landfill. All the claims about recyclability mean nothing if industries determine that recycling is too expensive.

This is where material value comes in. The higher the price of virgin silicon, silver, and aluminum, the more attractive recycling becomes. The article about renewable energy infrastructure noted that silver makes up about 14 percent of the material value of a solar panel.

Unfortunately, the value of the various materials inside a solar panel is still less than the cost to recover them. Without mandates for recycling, it will be a hard sell.

The Upshot

Solar power remains a key part of the transition to renewable energy. We are still many years away from the end of life of millions of first-generation solar panels. That, unfortunately, means that it is hard to generate a sense of urgency around recycling and recovery. Fortunately, we are hearing more talk about how to plan for recycling. Will that lead to action soon enough? Time will tell.