Optimal Hybrid Storage System Sizing to Provide Sustainable Energy to Subsea and Offshore Loads

Offshore energy platforms face unique challenges in integrating renewable energy sources with storage systems due to limited space, weight constraints, and the need for a resilient power supply to support critical subsea operations. To address these constraints, this study conducts the optimal sizing of three offshore renewable energy storage configurations—standalone battery (BESS), standalone hydrogen (HESS), and a hybrid system combining both technologies. Using a Mixed-Integer Linear Programming (MILP) model, each case study is optimized to minimize total system cost while meeting the energy demand of subsea loads, particularly during periods of low wind generation. The model accounts for platform constraints such as limited deck area, weight capacity, and container stacking rules, ensuring that all solutions are physically feasible for offshore deployment. The case study results have shown that while standalone systems offer partial advantages, the hybrid configuration effectively leverages the fast response of batteries and the long-duration support of hydrogen storage, achieving a resilient and balanced energy supply while respecting installation limitations.