POSEIDON is the EU's first commercial wave-to-hydrogen investment: a 50 MW plant combining wave-energy converters and PEM electrolysis at Žigljen (Island of Pag, Croatia), producing up to 7,960 t/year of renewable hydrogen (RFNBO) for North-Adriatic industry and maritime transport. The EUR 276.5 M investment, validated by an operational 1 MW pilot, will avoid ~97,000 t CO₂eq/year and provides a replicable blueprint for up to 2 GW of wave-to-hydrogen capacity along