Optimal Generation Scheduling for Electric Propulsion Ships with Variable-Speed Diesel Generators and Proton Exchange Membrane Fuel Cells Under Environmental Constraints

This study presents an optimal strategy for hybrid electric propulsion ships with variable-speed diesel generators (VSDGs) and proton exchange membrane fuel cells (PEMFCs). With the International Maritime Organization imposing stricter environmental regulations, shipboard power systems must satisfy emission limits and operational constraints cost-effectively. To address this challenge, a Lagrangian relaxation (LR)-based optimization framework integrating unit commitment and economic dispatch is developed. Practical operational constraints reflecting realistic shipboard conditions are incorporated. The effectiveness of the proposed framework was evaluated through simulation-based case studies under various realistic operating conditions. Simulation results show that the proposed LR framework achieves lower total fuel costs than conventional priority-list methods while complying with environmental regulations under diverse operating scenarios.