The article presents the technical - economic details of a hybrid power plant, towards 100% electricity production for the autonomous island of Sifnos, Greece, following the initiative of the Sifnos Island Cooperative (SIC) to claim the island's energy independence and a sustainable future for the local community. In the case of Sifnos, energy independency is achievable given the high wind potential and the availability of an appropriate site for the installation of a seawater Pumped Hydro Storage system. Despite the low power demand (annual peak demand 6.5 MW), pumped storage remains the optimum energy storage technology, with a set-up specific cost of 30 (sic)/kWh of storage capacity. The project's economic feasibility is ensured with a selling electricity total price of 0.29 (sic)/kWh, given the production specific cost (0.34 (sic)/kWh) of the existing thermal power plant. The hybrid power plant anticipates to constitute the kernel of the SIC objectives for a general social and economic development for the local community. This can be approached with the re-investment of the project's profits for the development of essential technical infrastructure and the exploitation of the electricity production surplus, combined with energy saving or smart-grid techniques, to foster new professional activities. (C) 2018 Elsevier Ltd. All rights reserved.