We have had much progress in decreasing the human carbon footprint over the last few decades. Solar power is popular, and the universal photovoltaic (PV) capacity, or the maximum electricity output a system can sustain, increased from 1.4 GW to 760 GW in only 2 years. Globally, 4% of all electricity is generated by solar power. The majority of this success can be attributed to solar panels, but this low-carbon miracle is on the clock. Within the near next few years, too many of these panels will expire and become trash. The waste from these expired panels can potentially have opportunities to retrieve valuable components and maybe even create new recycling jobs. But is recycling solar panels a worthwhile task? Experts say it's worth it and badly needed now.
What Are Solar Panels Made Of?
Most of the solar panel market is designed with crystalline silicon technology. Glass, copper wire, polymer layers, and silicon solar cells are contained within an aluminum frame with a junction box made of plastic. Exposure to the elements is protected by the layered polymer seals that are hard to take apart because high temps are needed to loosen its adhesive.
The solar cells are composed of silicon, aluminum, and silver wires all sandwiched together. The copper wire component connects the cells and is then melted together with lead and tin. A back sheet composed of polyethylene and PV panels is joined to the aluminum cased and topped with glass. Though there are thousands of these silicon panels, they are basically the same and once constructed, are meshed together into panels of full size.
Are Solar Panels Bad For The Environment?
Over 90% of PV panels are good for use for up to 30 years due to their crystalline silicon reliability. By 2030, about 8 million tons of paneling, and 80 million tons by 2050 will have reached their expiration date. Recycling these panels is ineffective and barely done with current technology. This is a bad predicament to be in.
Toxic materials are contained within PV panels. For example, lead causes pollution in the environment, but lead-containing panels are being dumped in landfills. The panel contains components that are valuable and can be reused, but they have mostly been wasted. The recoverable raw materials from expired panels globally will have a value of 450 million by 2030. This is equally about the cost to create 60 million new panels from raw materials. Rerouting solar panels to recycling from landfills captures valuable raw material, and landfill space is preserved.
Can You Recycle Solar Panels?
Solar panel recycling in the US is not federally mandated. Only about 10% of US panels are recycled, and the price to recycle presently costs tremendously more than just throwing them away. Efforts to recycle are very important because of toxic waste, and the potential for the PV industry in the future. Support is often a challenge due to those who are against new panel installations due to lack of effective recycling means. Because PV paneling is supposed to be “green”, but panel expiration and waste definitely are not.
Scientists and PV companies are working hard to get ready for the soon-to-arrive PV waste nightmare. It costs up to 45 dollars to recycle a PV panel here in the US, but less than 5 to take it to a landfill. So are solar panels sustainable...absolutely. Technology is being developed to retrieve more useful materials from panels. Things should look up soon if cheaper recycling methods are developed, and restrictions on landfill dumping are tightened.
How To Recycle Solar Panels
If put simply, there are 3 basic steps to recycling a solar panel:
- Take off the junction box and aluminum frame
- Via mechanical, thermal, or chemical means, separate the silicon wafer from the glass and/or
- Divide up the silicone cells and metals like tin, silver, copper, or lead, then purify them via electrical and chemical methods
But the separation of the components can be tricky. Most PV recycling will end after the easy portion of removing the aluminum frame and junction box. Recyclers often sell mixed and contaminated glass as cullet after shredding it with other solar components. This is because it is difficult to peel the glass cover from the underlying solar panels due to the EVA glue. After that, it is even more difficult to pull the metals apart to get a silicon wafer that is pure. Glass takes up most of the weight at 75% of the solar panel, and the recycling industry already has many options for glass sustainability. The copper wire, aluminum frame, and junction box are also easy to recycle.
Some scientists are using organic solvents to get rid of the EVA glue, but the process can create lots of hazardous waste and it can be expensive. Other companies burn off the glue at about 500 degrees Celsius, but processing huge panels will require an enormous oven and extensive energy. Another method uses infrared technology and a specialty knife to cut the glass paneling away. The original prototype was developed in Europe. The hope is that it can handle 5000 panels a year.
After the glass is removed, the expensive materials underneath are focused on. A chemical process that recovers metals and silicon has been developed using nitric acid to filter the metals. Then hydrometallurgy is used to separate silver and copper from the other metals. This process works, but in order to be green and cost-effective, 20,000 tons of panels annually need to be processed. The US is not yet at that point.
In the last 20 years, the installation of millions of solar panels has been completed. Since they last up to 30 years, soon many will be ready for retirement. Since we as a country do not want them to head to landfills with their toxic components, scientists and environmentalists are working tirelessy to create new recycling options soon to elevate the sustainability of solar paneling. The environment benefits and thousands of potential new jobs are created.