New Life for Old Modules

Photovoltaics manufacturers want to recycle disused solar panels.

Modules not only produce clean energy, they are also being taken back by the manufacturers at the end of their life to recycle their components. The voluntary take-back system in the solar industry, PV Cycle, is considered an important milestone on the way to a really green industry. However, problems are threatening the realisation of this scheme.

Photovoltaics (PV) and nuclear energy have one thing in common: Both produce energy. However, this is where the similarities end. While solar panels quietly capture the sun, nuclear power stations produce dangerous radiation and waste. What is left from the two types of power stations after decommissioning is also very different from each other: Radioactive kilns on one side, whose disassembly and disposal is a difficult task for engineers, and solar modules on the other side, which anyone can easily disassemble with a screwdriver and scrap.

However, modules are in no way green as a waste product, as they are made up of many components, some of which are toxic. A silicon module, for example, (depending on its weight) is made of up to 60% glass. The plastics for the laminating layers, the reverse foils, cables and terminal box as well as the aluminium for the frames add up to over 30 percent. The cell has contacts made of silver and is then soldered with other cells using lead. Thin-film modules are not any less harmless: Some are made from cadmium-telluride (CdTe), a composition of two elements, which are harmful to both the environment and health, if they are released. Other thin-film panels are based on copper. Depending on the process, indium, gallium, selenium and sulphur are mixed together with highly toxic cadmium sulphide, which protects the absorber layer.

Therefore, modules are not just household waste. They are actually similar in their composition to electrical equipment, such as flat-screen televisions. The EU makes it obligatory for the electronic industry, as a result of the WEEE Directive (Waste Electrical and Electronic Equipment) to dispose of their old equipment properly, i.e. to at least partially recycle the scrap. In this way, the manufacturers only receive approval for their electronics if they are involved in disposal proportionally to their quantity of goods and the equipment does not contain any dangerous substances.