Recycling of end of life photovoltaic panels. A chemical prospective on process development

The application of photovoltaics has been rapidly increasing over the past two decades driven by the idea that it could provide a fundamental contribution to the transition from traditional fossil fuels to renewable energy based economies. However, long-term sustainability of photovoltaics will be largely dependent on the effectiveness of the process solutions that will be adopted to recycle the unprecedented volume of end-of-life panels expected to be generated in the near future. Recycling is indispensible to avoid the loss of the valuable materials employed to produce the photovoltaic panels and, at the same time, prevent that harmful elements, including, for example, heavy metals, could be dispersed into the environment through improper disposal practices. In this article, the process solutions proposed over the past two decades to recycle photovoltaic panels are critically reviewed. Main objective is to provide the basis for the identification of the recycling solutions that can effectively sustain the continuous increase of the photovoltaic market. In order to assess the requirements that should be satisfied by the recycling processes, the legislation currently in force to regulate the management of end-oflife photovoltaic panels is reviewed, and the evolution of the PV market over the past two decades is analysed. Based on this analysis, forecasts are derived for the flux of end-of-life panels that will be generated over the coming four decades. A technical survey of the previously proposed recycling processes is successively performed by including, in addition to the analysis of the research studies published in scientific articles, a detailed review of the patented recycling processes. Indications are given to which may be the most promising processes in terms of their economic sustainability and environmental impact.