To support the International Maritime Organization’s (IMO) 2050 greenhouse gas reduction targets, hybrid propulsion energy management systems (EMS)—which integrate multi-energy coordination and dynamic scheduling—have become a critical pathway for enabling low-carbon transitions and improving energy efficiency in the maritime sector. This paper conducts a comprehensive and structured analysis of EMS technologies applied to ship hybrid propulsion systems. It evaluates the functional roles of EMS under varying system architectures, synthesizes mainstream energy management strategies, and identifies current technological bottlenecks, thereby contributing theoretical foundations for the green transformation of the shipping industry. The study first examines representative hybrid propulsion architectures, detailing their technical characteristics to clarify the functional positioning and optimization priorities of EMS in each configuration. It then reviews prevailing energy management and control strategies, with a focus on their integration with artificial intelligence (AI) and the emergence of adaptive and data-driven approaches. Finally, the paper identifies key challenges in hybrid propulsion EMS, proposes future research directions, and offers practical recommendations to support the advancement and implementation of intelligent energy management technologies in maritime applications.

Abstract
1. Introduction
2. Basic Types of Hybrid Power Systems
    2.1 Series Hybrid Power Architecture
    2.2 Parallel Hybrid Power Architecture
3. Energy Management Strategies 
    3.1 Rule-Based Strategies
    3.2 Optimization-Based Strategies
    3.3 Intelligent Algorithms
4. Current Challenges
    4.1 Dynamic Environmental Adaptability
    4.2 Multi-Objective Conflicts
    4.3 Hardware Limitations
5. Conclusion and Outlook
References

• Lixin Zhao(School of Naval Architecture and Port Engineering, Shandong Jiaotong University, Weihai 264209, China)
• Chengmeng Sun(School of Naval Architecture and Port Engineering, Shandong Jiaotong University, Weihai 264209, China)
• Haihua Lin(School of Naval Architecture and Port Engineering, Shandong Jiaotong University, Weihai 264209, China) Corresponding author