A new framework to green hydrogen production from ocean/sea renewable energy sources: A case study of the Türkiye

This study introduces a novel techno-economic framework for green hydrogen production by integrating Ocean/Sea Current Turbine (OCT) technologies with desalinated seawater electrolysis. The proposed framework stands out in the literature by combining a geospatial location selection model, optimal technology matching, and detailed cost modeling under current (2024) and future (2050) scenarios. The methodological innovation lies in the use of a Multi-Criteria Evaluation Index (MCEI), developed through the Step-wise Weight Assessment Ratio Analysis (SWARA) method, to evaluate eight geographically and technologically relevant criteria, enabling a robust, transparent, and scalable site selection process. This study applied and tested the proposed framework in Türkiye, where ten candidate coastal locations were assessed as a case study. Based on elimination and evaluation criteria, the Kilitbahir site in the Çanakkale Strait—characterized by a high sea current speed (2.3 m/s) and optimal seawater properties—was identified as the most suitable location. A 2 MW pilot facility configuration was modeled using a SeaGen-S turbine, a PEM electrolyzer, and a Reverse Osmosis (RO) desalination unit. Hourly hydrogen production is estimated at 22.413 kg for 2024, increasing to 37.137 kg by 2050. From an economic perspective, two distinct Levelized Cost of Electricity (LCoE) formulations were applied to capture cash flow dynamics, inflation, and performance degradation. LCoE values for 2024 ranged between 98.24 and 100.66 USD/MWh, decreasing to between 42.24 and 42.85 USD/MWh by 2050. The Levelized Cost of Hydrogen (LCOH) for 2024 was calculated at 8.808 to 8.973 USD/kg, dropping to 2.34 to 2.365 USD/kg in the 2050 projection. This study's novelty lies in its integration of spatial decision-making, emerging marine technologies, and forward-looking economic modeling. The proposed framework offers a replicable pathway for green hydrogen deployment in coastal regions worldwide and provides policymakers and investors with actionable insights into future cost trends and siting strategies.