Introducing the cold-ironing technique and a hydrogen-based hybrid renewable energy system into portsIntroducing the cold-ironing technique and a hydrogen-based hybrid renewable energy system into ports Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2024-02-092022enNatural resources’ unexpected nature makes renewable energy sources’ power supply irregular and inflexible; weather conditions are impossible to be predicted. Energy storage systems are required to balance this green power supply and ensure both off-grid and autonomous infrastructures' stability and reliability. Various energy storage technologies are available, but the high initial capital cost and the uncertainty regarding future cost and performance are critical bottlenecks for possible investors. Batteries are the most common energy storage means, while hydrogen storage is one of the least used options. This research attempts to conduct a comparative technoeconomic analysis between a hybrid renewable energy power plant combined with a hydrogen energy storage system and the implementation of the cold-ironing technique. The test bed is the port of Milos, which is a Mediterranean island port. Thirteen scenarios were conceptualized, simulated, and assessed after examining and assessing the existing methods and technology using MATLAB and Homer Pro software. The economy of scale plays its role in this aspect as hydrogen storage systems' cost has been proven to be lower for larger infrastructures. Indicatively, the levelized cost of energy is significantly reduced for the two optimal scenarios, as there is a 41.3% decrease for the non-cold-ironing case and a 33.4% decrease for the cold-ironing one. Moreover, the carbon footprint for the suggested systems of all the examined scenarios is almost diminished, paving the way forward for turning the port into a nearly Zero Energy Port. This study also helps to comprehend the technoeconomic characteristics of hydrogen-based hybrid renewable energy systems for supporting the cold-ironing technique.http://creativecommons.org/licenses/by/4.0/International Journal of Energy Research461420303–20323 Sifakis Nikolaos Σηφακης Νικολαος Vichos Emmanouil Βηχος Εμμανουηλ Smaragdakis Angelos Σμαραγδακης Αγγελος Zoulias Emmanouil Tsoutsos Theocharis Τσουτσος Θεοχαρης Wiley Energy efficiency Ηybrid renewable energy systems Hydrogen storage systems Nearly zero energy ports