Green electrification and carbon neutrality are of critical importance for the future of the Mediterranean area (MED) because it is expected to suffer more than other areas from climate change. The path to decarbonization requires the electrification and digitalization of the power infrastructure with the deployment of innovative energy systems. Future energy solutions must be based on Renewable Energy Sources (RES) to replace the existing fossil fuel-based power generators. To increase the RES share and accelerate this transformation to a more sustainable energy future, it is required to develop decentralized systems with a high level of operational flexibility. Solar energy is abundant in the MED area, but due to its intermittent nature, solar Photovoltaics (PVs) cannot satisfy electrical energy demand as standalone systems. A possible way to increase self-sufficiency and RES share is to couple PV modules with Energy Storage Systems (ESS) and Demand Side Management (DSM). The BERLIN project has been created with the aim of materializing these targets, and to create a new paradigm under the concept of hybrid nanogrid PV-ESS-DSM systems. The current paper describes the components, configurations, and operating principles of the hybrid PV-ESS-DSM nanogrid demonstration systems that are currently under development.