Renewable-Hydrogen Sector Coupling for Electricity and Ferry Decarbonization on a Non-Interconnected Island: A Feasibility Assessment of Gavdos, Greece

Gavdos is assessed as a non-interconnected island without mainland electricity exchange over the adopted planning horizon. A configuration with 340 kWp of photovoltaics, an 800 kW wind turbine, and surplus-fed electrolysis is evaluated for electricity supply and ferry hydrogen. Twelve public HEDNO monthly day-ahead files were concatenated into an 8760 h rolling-year demand series. RETScreen-based F-chart solar calculations and a Weibull wind distribution (k = 2) provided twelve representative monthly 24 h renewable profiles, mapped by month and hour to the dispatch chronology. Renewable generation first serves demand; deficits are assigned to conventional generation and surplus to electrolysis. Annual demand is 662.630 MWh, of which renewables supply 650.633 MWh directly (98.19%); the residual deficit is 11.997 MWh across 419 h. The 302.6 kW baseline electrolyzer produces 34.488 t H2 year−1 gross versus a ferry demand of 33.890 t H2 year−1. Although daily production is lower than demand in 130 days, accumulated hydrogen keeps the gross inventory non-negative. The maximum seasonal drawdown is 947.4 kg, giving a usable hydrogen-mass requirement of 1133.1 kg including a two-day reserve. The results demonstrate gross-production compatibility under the adopted assumptions; net ferry-fuel adequacy requires detailed assessment of component operation, auxiliary loads, storage, delivery, and vessel duty.