Climate change, mainly caused by the GHG emissions increase, is threatening our planet and a huge energy transition is needed, including the decarbonisation of energy sources, a larger and larger penetration of renewables (with the dramatic growth of wind and solar intermittent energies) and the necessary development of energy storage technologies. The integration of RES in hydrogen-based P2P storage systems is the most credible option with medium/long-term capacity and H2 can be also used as a clean energy vector, flexibly transportable across different sectors and regions. In particular, islands and remote areas can become isolated mini-grids based on RES and P2P systems, avoiding more expensive and impacting solutions, such as submarine electric connections or on-site diesel generators, and having a huge global development potential.