Expanding solar power generation is the key to reducing global emissions.Solar panels produced globally 720 TWh In 2019, it will account for about 3% of global power generation.It took about 46 million tons Solar panels do this.
By 2030, the world may accumulate about 8 million tons of decommissioned solar panels.By 2050, this number may reach 80 millionRecycling these panels can provide a new source of materials that originally needed to be mined (maybe in unsafe or Exploitative working environment), making solar energy a more sustainable part of the clean energy problem.
What’s in the solar panel?
The solar panels are laid out like a sandwich with batteries in the middle. About 90% of commercial solar panels use silicon as a semiconductor to convert light into electricity. Thin metal strips (usually silver) criss-cross on the surface of the silicon crystals in each cell and deliver current to the copper wires of the panel.
The solar cells are wrapped in a protective barrier, usually a transparent plastic called EVA. Another layer of glass is placed on top, and another plastic, such as PET, is covered on the back. The whole thing is surrounded by an aluminum frame.
This layered structure protects cells from elements while allowing sunlight to pass through, but it may be difficult to deconstruct when the panel reaches its end of life.
Some companies try to refurbish and reuse panels that have lost their efficiency, or at least save some of their components. Reuse is the simplest and cheapest way to “recycle” panels-it requires the least processing and requires the highest price.
The price of a panel may be about US$55, while the resale price of a second-hand panel is about US$22. Or, the total selling price of used panel components may be as high as $18. Meng Tao, An engineering professor at Arizona State University, and the founder of a solar panel recycling startup called TG Companies.
Although some dealers provide second-hand panels to residential customers, they do not offer much price savings. Panels account for only about half of the cost of residential solar arrays, while other equipment and permits account for the rest. Given that used panels do not generate as much electricity, the money saved by buying them may not be worth the money.
Old panels that cannot be resold will be used in landfills or some type of recycling. Without federal authorization, Washington Recycling requirements for manufacturers were recently passed, and other states are now considering doing so. At the same time, the European Union requires manufacturers to collect and recycle used solar panels and provide research funding for end-of-life solutions for the technologies they produce.
Some waste treatment facilities can use mechanical methods to recycle solar panels. Most are ejected from an aluminum frame and grind all glass, silicon and other metals into a mixture called cullet, which can be used in building materials or other industrial applications.
But the value of broken glass is not high—a mix of panels is worth about $3. Tao said that it is unclear whether there will be buyers for the broken glass produced by recycling more solar panels. Being able to extract pure, valuable materials may help make recycling more profitable.
In 2018, Veolia, a waste management company headquartered near Paris, opened the first recycling line specifically developed for recycling solar panels. The plant is located in Rousset, France and also uses a mechanical recycling process, but because it is designed for solar panels, it has more components recycled separately than facilities that use general electronic waste recycling equipment. But some companies are betting that other methods, such as thermal and chemical processes, will be more effective.
Excavating old panels
ROSI Solar, a French start-up company founded in 2017, recently announced plans to build a new recycling plant in Grenoble, France. ROSI CEO Yun Luo said that the company has developed a process to extract silver, silicon and other high-value materials from scrap panels. According to the contract of the French trade association Soren, the factory should open before the end of 2022.
Soren is also working with a French logistics company called Envie 2E Aquitaine, which will try to find other uses for decommissioned solar panels. Luo said that if the panels fail to work, the company will remove the aluminum frame and glass, and then hand them to ROSI for recycling.
ROSI focuses on recycling silver and solar-grade silicon, as these two materials account for more than 60% of the cost of the panel. The company uses a proprietary chemical process on the remaining layers, focusing on removing the tiny silver wires that transmit power through the working solar panels.
Luo declined to give specific details, but said the company can recycle almost all silver in solid form, so it is easier to separate from other metals such as lead and tin. Luo said the company also recycles silicon in a pure enough form to be reused in new panels or electric car batteries.
Luo said that in order to be profitable, ROSI needs to recycle at least 2,000 to 3,000 tons of panels per year. Soren expects to collect about 7,000 tons of panels by 2021, and this number may more than double by 2025.