Since the beginning of the 2000s, national and EU research projects have been underway to develop the basic recycling processes of solar modules for the various PV technologies. In this context, the ZSW has been able to demonstrate the basic feasibility of recycling CIGS thin-film PV modules.
One feature that all PV technologies have in common is that their largest component by weight is glass, and that a very strong bond between the glass and polymers is formed in order to guarantee a service life of more than 30 years. This very strong bond is extremely difficult to break down, however, and is therefore the greatest challenge for an economic recycling of end-of-life solar modules.
Today, only the components aluminium frame, cables and the junction box, and the glass are recovered. The other metallic materials, manufactured in processes consuming large quantities of energy and resources, are lost since none of the processing methods developed in research projects to date have proven to be economically viable. Since recycling quotas are stipulated by law, a levy paid by the manufacturers and importers of solar modules supports the cost of recycling solar modules in Germany and Europe.
Germany was a pioneer in the installation of solar modules and was the largest single market until 2015. This means that relatively large and therefore commercially valuable quantities of end-of-life solar modules are expected to be available for recycling in Germany in the coming years. A long-term recycling infrastructure is thus becoming significantly more relevant.
In the ‘PeroCycle’ project currently being funded by the German Federal Environmental Foundation (DBU), research is being conducted with partners Solaveni GmbH, Solar Materials GmbH and ZSW on a recycling process for perovskite solar cells. Perovskite solar cells are a promising new type of PV technology that is ideally suited as a top cell in a tandem composite with silicon or other solar cells. As PV modules containing perovskites could reach a market share of 10% by 2034, consideration should already be given now to the disposal of the modules once they have reached the end of their service life.
