# Energy Transition on Sifnos: An Approach to Economic and Social Transition and Development
## 7 Conclusions
In this way, the main issue of insularity with regard to the regular, secure and cheap transportation connection of Sifnos throughout the year is once and forever solved using a sustainable and environmentally friendly approach. The sizing of the hydrogen production and storage plant was established based on the computational simulation of its annual operation, proving the feasibility of the proposed perspective. The project is finally anticipated to provide a significant contribution to the touristic visibility of the island, based on the condition of a proper promotion campaign of the island as the first truly green island in the world. Additionally, with the proposed project, the island will have a guaranteed power production plant installed in the insular territory, based on the exploitation of RES, which can ensure a secure energy supply and the improvement of the electrical grid's dynamic security and stability. The plant's ancillary services will be further strengthened with the anticipated implementation of parallel, accompanying activities and projects on the island, such as the execution of peak shaving and load shifting with decentralized power production and storage, supported by the development of a local smart grid, or the introduction of energy-saving measures in all sectors on the island (residences, municipal and tourist facilities, etc.). All of these measures will lead to the reduction in both the electricity production and, more importantly, the power demand drop, offering the margin for the more flexible operation of the hydro turbines and further strengthening the overall electrical system's stability. The electricity interconnection of Sifnos with the mainland grid cannot ensure the electricity supply's security and the insular grid's stability without the maintenance of guaranteed power production on the island. The only way to do this in the frame of energy transition, namely without the use of thermal power plants, is the proposed hybrid power plant. At the same time, the necessity for electricity storage has been officially recognized by the Greek state also for the mainland system. The relevant legislation framework is already adapted, in order to support the installation and ensure the feasibility and viability of storage plants on the Greek mainland and in insular grids. A crucial parameter to ensure the hybrid power plant's economic viability, which will actually enable the construction of the project and the fulfillment of all of the above objectives and perspectives, is the electricity selling price, which still remains unknown. With a price of EUR 0.26/kWh, the investment's payback period is calculated at 8 years. Given the recent significant increase in the electricity production cost and its procurement prices for the final consumers, this price has become highly competitive. This price can be reduced to in the range of EUR 0.15/kWh after 15 years of normal operation, namely after the payback of the banking loans. Conclusively, the proposed hybrid power plant is the only way to achieve the two fundamental objectives of energy transition, set also as essential targets of the scheduled interconnection of the island with the mainland grid:  
* the significant reduction in the electricity production specific cost
* the elimination of the dependency of the insular power system on thermal generators and imported fossil fuels. Summarizing the above, this article proves that energy transition represents an approach for sustainable and viable development for insular communities, starting from local citizens. It proves that energy transition can constitute the lever for social and economic development for all, once the optimum technologies are utilized at the appropriate scale, aiming to cover all alternative final energy uses (electricity, onshore and offshore transformations), sited properly to avoid any impacts on and disturbances to the natural and human environment and, most importantly, with the active involvement and participation of the local community.