The most abundant and affordable form of renewable energy is provided by solar panels. However, are there any harmful consequences on the environment, and if so, how should we handle them?
Let's first look at some facts.
In the 1980s, the first photovoltaic solar panels that were linked to the grid were set up. While some of the new versions are now supplied with a 30-year warranty, some of them are still in use decades later.
At the end of their useful life, solar panels, which are complex technological devices, break down into big, clunky sheets of electrical garbage. Consider this: With a 30 year lifespan, end-of-life solar panels are estimated to generate 8 million tonnes of garbage globally by 2030 and 80 million tonnes by 2050.
So, are solar energy systems bad for the environment?
There is no risk of contaminants seeping from intact or broken panels, according to the German Environment Agency (UBA). The majority of models do, however, have trace amounts of dangerous compounds for the environment.
For instance, the solder in the 95 percent of crystalline solar modules now in use includes up to one gram of lead per module. Some producers don't even utilize harmful lead.
The cells in so-called thin-film modules (which account for around 5% of the market) also include harmful heavy metal cadmium in amounts of up to 1.4 grams per panel. The makers of these panels do, however, have a take-back program of their own where they recover non-hazardous metals like silver, copper, and tellurium as well as dangerous elements like cadmium and lead.
Unfortunately, while abandoned modules must be properly disposed of in Europe, these requirements are still lacking in the majority of other nations. With the help of the guidelines, solar panels won't decay in the open air and eventually release pollutants. Solar panels also include important raw materials that may be recycled in them.
How does recycling now operate?
The crystalline panels are destroyed, the aluminum frames, wires, and junction boxes are taken out, and different methods are used to separate the glass, metals, and foils. Glass shards are often processed into glass wool, a type of thermal insulation, while metals and lead are removed and reused. To create energy, the plastic foils are burned in plants equipped with filters. Experts in the fields of raw materials and the environment agree that recycling still has a long way to go. They would like that high-quality solar glass from previous modules be utilized for that instead of the existing practice of using subpar insulating materials. It has just recently been utilized as an addition in the manufacturing of aluminum.
Scientists from Nanyang Technological University, Singapore (NTU Singapore) and the Agency for Science, Technology, and Research (A*STAR) may have discovered the solution to this growing issue.
According to a study that was published in the journal Advanced Materials, the researchers have created a unique method that can turn old solar panels into a novel high-performance energy-harvesting thermoelectric material that absorbs heat and transforms it into electricity.
Converting a constraint into a chance
As was already noted, silicon, aluminum, copper, silver, lead, and a complex amalgam of other components make up solar cells. It is challenging to recycle each component of a solar panel independently. And to make matters worse, recycled silicon includes flaws and impurities that render it unusable for the production of solar cells.
In the most recent investigation, the researchers chose to take advantage of this restriction by transforming used solar cells into improved thermoelectric material. This technique makes use of thermoelectrics' unique properties, which differ from solar cells in that impurities and flaws tend to enhance rather than degrade performance.
Helpful in the production of components for renewable energy sources
The researchers were able to accomplish this by using ball milling technology to ground solar cells into a fine powder, which gave them the opportunity to endow wasted silicon with thermoelectric features such as power conversion and cooling efficiency. Phosphorus and germanium powder were then added to the powder combination to alter their original characteristics before being subjected to spark plasma sintering at a high heat and temperature.
The researchers created a sample with the greatest thermoelectric performance among elemental silicon thermoelectrics, with a thermoelectric figure of merit (zT) record-high of 0.45 at 873 K. This is very significant since these technologies have the potential to increase the lifespan of many items and decrease waste in order to promote a circular economy.
According to co-corresponding author NTU Associate Professor Nripan Mathews, the Cluster Director of Renewables & Low-Carbohydrate Energy, "We have demonstrated that it can yield valuable materials that are of high quality and useful in the manufacturing of renewable energy components, which in this case is the development of a high-performance thermoelectric material that can harvest heat and turn it into electricity."