End-of-life of renewable energy technologies in urban environments. A state-of-the-art on installation trends, materials, and best practices in the EU

The European Commission is promoting the production of thermal energy and electricity from renewable sources, coupled with storage systems, to decarbonize the built environment. However, these technologies use prevalently virgin raw materials, and end-of-life (EoL) circular frameworks are still difficult to be implemented due to technical, regulatory, and market barriers. This paper aims to present a state-of-the-art on the trends in installation, materials, EoL strategies, and companies active in renewable energy systems recycling. Solar, wind, and geothermal sources are examples of technologies easily incorporated into cities. The purpose is to provide information to stakeholders that should design technical solutions according to circularity criteria. The information, from both scientific and grey literature, showed that solar technologies represent the most widespread type of systems, with a considerable number of best practices and companies specialized in recycling. Wind technology follows in installation trends and activity of reuse-oriented companies. Geothermal, on the other hand, offers a reduced number of reference examples. Furthermore, this review provides an overview of the installation and potential EoL scenarios of electrical and thermal energy storage systems, highlighting significant differences in the implementation of circularity strategies. The study closes with considerations and suggestions for practical applications.