Solar power-to-gas application to an island energy system

Geographical Islands have been considered a challenge environment to test renewable energy integration strategies as well as cutting-edge technologies due to the alternation between actual grid-connected and island mode. This is due to the weak connection to the mainland and, subsequently, the Power Grid as well as the strong changes in seasonal energy demand leading to congestion and stability issues. Hydrogen technologies could be the pathway to mitigate the afore-mentioned issues providing bi-directional energy exchange as in the case of reversible solid oxide cells or interacting with other sectors such as transport by fuelling fuel cell vehicles by means of H2 produced by electrolysers. The scale of renewables locally installed plays a key role and this is why the amount of surface dedicated to solar energy exploitation as well as the number of buildings involved in the design are crucial. Therefore, in this paper a sensitivity analysis is carried out between 1 and 3 buildings, i.e. 20–100 kW of committed electrical power located in the Island as well as the surface dedicated to PV array for local production. The hydrogen energy system layouts of the simulated scenarios are optimized by the adoption of the ©E-OPT software platform based on a Mixed Integer Non Linear Programming solver. The scale affects the choice of the best hydrogen technology to integrate in order to increase the self-sufficiency of the compound and, consequently, the energy security of its supply. Furthermore, when coupled with CO2 emissions the performance vary with the final use of the stored hydrogen.