A solar panel is a device that collect the energy of the sun, which reaches Earth in the form of solar radiation and converts it into electricity. Ok, it's actually a bit deeper than that. What is regarded as "solar panel" is in fact a photovoltaic panel, as these are the devices responsible for converting solar radiation into renewable electricity.

Real solar panels turn the sun rays into heat, which is usually used to warm up the water used by a household. So, to summarize, photovoltaics produce electricity and solar panels, heat, but for simplicity, we will be using solar panels to describe the first category.

The first modern solar panels that are similar to those that we use today have been developed in 1954, but they only reached commercial stage in 1956. However, the price was very high, at 300 USD per watt of energy produced, while in 1975, they reached a much easier to swallow 100 USD per watt.

The reason why they're found virtually everywhere today and a large number is being installed as we speak is that the price reached a historic low in recent years, at around 2-4 USD per watt. Solar panels are used for a variety of purposes, including powering small devices, such as surveillance systems, sensors and alarms, but can be employed to power entire homes, as well, if coupled with a battery system. This is required so that the large flow of energy required isn't interrupted in case the sun briefly goes behind the clouds.

How long do solar panels last and how to recycle them

Just like anything in this world, solar panels don't last forever, even though since they were first introduced, their lifespan increased significantly, to around 25-30 years on average. When it's time to recycle the panels, you should contact your closes recycler that specializes in reprocessing these devices. Note that solar panels can't be recycled by all companies that usually take care of ordinary used electronic devices.

In Romania, Romec Green is one of the electronic waste companies that can recycle photovoltaic panels.

There are currently two commercial types of solar panels out there, crystalline-silicon-based solar panels and thin-film models, both requiring different approaches to recycling. Crystalline solar panels are the most ubiquitous model out there and it is built on an aluminum frame, with glass, copper wire and polymer (plastic) layers. There are other components here, as well, but they are mostly made of the same materials, so I won't list every single component for simplicity.

The polymer layers have the purpose of protecting the solar panel from the elements, but these usually slow the recycling process down, as high temperatures are required to separate them from the rest of the panel.

The good news is that most of the solar panels' components can be recycled and glass is one of the main parts. It represents around 75% of the weight of a panel and the glass recycling industry is developed enough. The other materials that are easy to reprocess are the aluminum frame, the plastic junction box and the copper wiring.

Silver and internal copper are two other materials that are easy to reprocess, but they aren't found in large amounts and the respective locations require careful opening of the units themselves, while toxic materials, such as lead and cadmium, can also be found.

Frist of all, the aluminum frame and the plastic junction box need to be removed from the overall system, which is followed by the separation of the glass and the silicon wafer through thermal, chemical and or mechanical processes. Then comes the separation and purification of the silicon cells and the metals via chemical or electrical techniques.

The situation is different and more complicated for thin film solar panels, which are fewer compared to the silicone models and are made of a cadmium-telluride composite. These are more difficult to recycle and there aren't as many companies that can properly process them. Their main component is a semiconductor material, which is made from the aforementioned composite, in addition to glass and copper. Due to the cadmium's toxicity, these need careful handling and processing.

Solar panels advantages and drawbacks

Solar panels have a suit of upsides, such as the fact that they are a well-established renewable energy source, as well as a way to reduce the electricity bill at home and at work. They have reduced maintenance costs and if they don't get damaged, can last up to 20-30 years.

The drawbacks are usually the cost, especially for large installations that surpass 100.000 kWh or 1 MWh, while they're also weather dependent. This doesn't only refer to the fact that the sun is required for energy to be produced, but also the fact that the panels themselves can be damaged during a hail storm or a tornado.

They can also take up a lot of space, especially if not installed on a rooftop, while they can be associated with pollution, if they end up in landfills or aren't recycled properly. Used solar panels can also be upcycled for various applications, but maybe we'll write this in a different article.

The recovered materials can be reintroduced in the economy in the form of new products, including new solar panels, but based on the different materials, plastic, glass and the metals, the possibilities are endless.