Solar power is now the fastest-growing energy source in the world. An estimated 500,000 solar panels were installed globally every day in 2015. The typical American home requires 28 to 34 solar panels to produce 100 percent of its energy consumption.

As the solar energy industry grows, there is a looming waste management issue. What will happen to the millions of solar panels now dotting rooftops across the globe at the end of their useful lives?

Few Solar Panel Recycling Options Exist Now

At the moment, most countries do not have a robust recycling infrastructure in place for solar panels. Most of the solar panels disposed of each year are damaged or defective. Because solar is a relatively young industry, the annual decommission rate of of solar power systems is still low.

The design life of a solar panel is roughly 20 to 30 years, and most solar panel manufacturers provide a performance guarantee to protect solar system owners. The guarantee offers solar homeowners peace of mind that the solar panels will generate a certain amount of power, barring unexpectedly cloudy weather. Many manufacturers guarantee 90 percent production after 10 years and 85 percent after 25 years.

Solar panels become less efficient over time, and performance guarantees protects consumers if the energy production declines prematurely. Most of the systems installed in the 1980s are still churning out an acceptable amount of power. The day will come, however, when a robust recycling infrastructure will be needed because more solar systems will be decommissioned.

Creating an Infrastructure

Given the design life of solar panels, we can expect a surge in solar panel disposal in the early 2030s.

“By 2050, global photovoltaic panel waste will have accumulated to an estimated 60 to 78 million tons, according to a report by the International Renewable Energy Agency (IRENA).” Although we need a relatively modest recycling capacity today, this trend will change, especially if solar growth forecasts are correct.

It’s important for these panels to be recycled; otherwise, valuable resources that could be used to make more solar panels will end up in landfills. Additionally, solar panels contain heavy metals, such as cadmium and lead, which could leach into the environment if not properly recycled. Solar panels also can contain rare elements, such as gallium and indium, that are slowly being depleted. Recycling these materials helps conserve supplies of these finite resources.

A Complex Product to Recycle

Recycling solar panels is a relatively complex task because they contain many different types of materials. Panels contain metals, such as lead, copper, gallium and cadmium; an aluminum frame; silicon solar cells; and synthetic material that encapsulates the silicon. The various materials must be separated to be properly recycled. Undamaged solar cells, for example, can often be recovered and reused in new products.

Solar panel recycling has both tremendous environmental and economic benefits. A 2016 study by IRENA estimates the recyclable materials in old solar modules will be worth $15 billion in recoverable value by the year 2050. IRENA predicts solar panel recycling can help spawn new industries and will create green job opportunities.

Learning from Europe

PV Cycle, a European solar panel recycling association, developed a mechanical and thermal treatment process last year that achieves a 96 percent recovery rate for silicon-based photovoltaic panels. The remaining 4 percent is utilized in an energy recovery process, using a waste-to-energy technology. The previous recovery rate for silicon-based panels was around 90 percent, so this new solar panel recycling process is good news for the environment. Non-silicon-based solar panels can have a recovery rate of up to 98 percent.

In Europe, the European Union’s waste of electrical and electronic equipment (WEEE) directive dictates solar panel disposal guidelines. In the United States, however, such guidelines do not exist except in California. Solar panel recycling guidelines in Europe could help spur innovation in the U.S., which could have global environmental and economic benefits.

As the cost of solar energy falls, solar energy capacity will grow. The higher the growth rate, the more decommissioned solar systems there will be that need to be recycled in a few decades. It is important to prepare for much larger quantities of photovoltaic solar waste to best capture the economic and environmental benefit of solar energy.

Feature photo courtesy of Shutterstock

Editor’s note: Originally published on April 6, 2017, this article was updated in September 2018.

By Sarah Lozanova

Sarah Lozanova is an environmental journalist and copywriter and has worked as a consultant to help large corporations become more sustainable. She is the author of Humane Home: Easy Steps for Sustainable & Green Living, and her renewable energy experience includes residential and commercial solar energy installations. She teaches green business classes to graduate students at Unity College and holds an MBA in sustainable management from the Presidio Graduate School.