Sifnos Island Cooperative (SIC) is an energy cooperative with the aim to realize the energy autonomy plan for Sifnos. SIC’s project refers to a Hybrid Power Station consisting of a wind park and a pumped storage plant. It is foreseen to have the capacity to generate all the energy required in Sifnos through only Renewable Energy Sources (RES). All new facilities to be installed, will become a key objective of protecting the environment and the tourism product of the island, which is expected to increase. According to the conducted study, the investment will be profitable from the first year of operation of the Hybrid Station and will continue to be profitable throughout, as the energy demand is secured. The Hybrid Station will be owned by Sifnos Island Cooperative, in which all major decisions are made by the General Assembly, equal members of which are all partners with one vote each. The vision is to make Sifnos energy autonomous by utilizing its inexhaustible RES, thus, shielding the society and economy of the island. The electricity will be generated from RES installations jointly owned by the inhabitants and the friends of the island who will be prosumers (producers and consumers at the same time).