This chapter thoroughly reviews the polymeric resorbable nanocomposites (PRNs) and their development towards a more eco-friendly and clean energy technology. The chapter first presents the major groups of naturally occurring and artificial resorbable polymers that are the basis of these composites. It then proceeds to discuss the very concept of nanocomposites and the reasons behind their positive impact on material properties. After that, the chapter exposes the primary methods of synthesis and fabrication critically, showing the vital dependency between the mechanical properties, the microstructure, and the processing route. Lastly, the chapter reports on the recent advancements and utilization of PRNs in the clean energy sector with particular emphasis on fuel cells, supercapacitors, and bio-degradable energy storage systems. In this way, the chapter ends by signposting future research paths and, at the same time giving a futuristic vision on the capacity of these new materials to contribute to the technological sustainability of the Earth.