# Energy Transition on Sifnos: An Approach to Economic and Social Transition and Development
## 5 Extensions
### Development Perspectives
Given the hydrogen-specific consumption of 3 kg/nm, the daily amount of hydrogen required for this voyage will be 330 kg, which, for the needs of the simulation, can be assumed to be removed from the hydrogen storage tanks at 12:00 every day. The previously presented algorithm is executed iteratively for alternative scenarios for the main components of the hydrogen production and storage plant, namely the electrolysis unit's nominal power and the storage tanks' storage capacity and nominal power. The results are summarized in \[\rm ii.\qquad if\ P_{\rm sur}\leq P_{\rm el},\ P_{\rm REsel}=P_{\rm sur}\]2  
\[\rm ii.\qquad if\ P_{\rm sur}\leq P_{\rm el},\ P_{\rm REsel}=P_{\rm sur}\]3 Map of the potential circular ship voyage for the daily maritime connection between Sifnos and the neighboring islands. It is conceivable that the potential hydrogen production from the hybrid power plant's electricity surplus is capable of fueling the regular, daily, cheap, secure and sustainable maritime connection between Sifnos and the most important nearby insular centers of the Cyclades Prefecture. Another important contribution from the hybrid plant is the remedying of the major problem regarding potable water availability, which is common for all small islands in Greece. Assuming an electricity-specific consumption of 4 kWh/m\({}^{3}\) in the reverse osmosis desalination process, 1,250,000 m\({}^{3}\) of potable water can be produced annually by exploiting 5000 MWh from the annual electricity surplus. This amount is roughly two times higher than the current annual potable water consumption on the island. This increasing potable water availability can be the basis for the development of new professional activities, such as biological agriculture and stock farming, which today are not implemented precisely due to the lack of water [68]. These new professional activities will expand the local economy and will enable its disengagement from its high dependence on tourism. The above perspectives demonstrate the multi-level contributions provided by the proposed hybrid power plant on Sifnos for total energy transition, through the coverage of the overall energy needs on the island and the establishment of significant developmental perspectives. At the same time, the introduction of new electrical loads into the insular grid will increase the electricity demand and will strengthen the economic viability of the hybrid plant. Obviously, the implementation of the aforementioned plans should be approached with the construction of the required infrastructure and facilities: hydraulic networks, water storage tanks, desalination units, electrolysis units, hydrogen storage tanks and a hydrogen-powered passenger ship. All these facilities can be implemented by investing the anticipated profits from the hybrid power plant's operation, as well as by claiming funding in response to national and European calls for new innovative and pilot projects. \begin{table}
\begin{tabular}{c c c c c} \hline  & **Scenario 1** & **Scenario 2** & **Scenario 3** & **Scenario 4** \\ \hline Electrolysis nominal power (MW) & 4 & 5 & 5 & 5 \\ Hydrogen tanks storage capacity (m\({}^{3}\)) & 500 & 500 & 400 & 500 \\ Hydrogen tanks nominal pressure (bar) & 300 & 250 & 300 & 300 \\ Hydrogen annual demand (kg) & 120,450 & 120,450 & 120,450 & 120,450 \\ Hydrogen annual supply (kg) & 118,800 & 118,800 & 118,140 & 120,450 \\ Annual electricity consumption (MWh) & 6767 & 6655 & 6597 & 6857 \\ \hline \end{tabular}
\end{table} 
Table 4: Summary of results from the iterative calculation process of the hydrogen production and storage plant. Figure 17: Annual pressure fluctuation in the hydrogen storage tank. Finally, with regard to the hybrid plant's contribution to local development, it should also be mentioned that it is expected to strengthen the offered tourist product on the island.