# Electrification in Maritime Vessels: Reviewing Storage Solutions and Long-Term Energy Management
## 1 Introduction
### Rise of Electric Vessels and Their Power
Additionally, integrating battery management systems (BMSs) is crucial for monitoring performance, ensuring safety, and optimizing charging and discharging cycles. As electric marine technology evolves, the role of batteries will become even more central, driving improvements in vessel efficiency, operational range, and overall environmental impact. However, considering the current limitations in the range and capacity of electric batteries, hybrid systems are often preferred over purely electric ones, especially in the early stages of the transition to sustainable maritime transportation. While all-electric vessels offer clear environmental benefits, the technology behind electric propulsion is still evolving, particularly in terms of energy density, charging speed, and the capacity to support long-distance voyages or large cargo loads [16]. Hybrid systems, which combine traditional fuel-powered engines with electric propulsion, provide a practical solution to these challenges [17]. They allow vessels to benefit from the efficiencies and environmental advantages of electric power while still relying on conventional fuel when needed to extend range or ensure operational flexibility. Hybrid vessels can operate in purely electric mode during short trips, in urban areas, or on emission-restricted routes, while seamlessly switching to fossil fuels for longer journeys or when battery capacity is low. This dual-power approach allows for gradual integration of electric technology into the maritime sector, while still meeting the demands of industries such as cargo shipping, ferry transport, and offshore operations, where long distances and high-power requirements are typical. Additionally, hybrid systems help mitigate the risk of relying solely on electric power during the current phase of battery technology development [18]. As battery technology continues to improve, hybrid systems will likely evolve, eventually leading to fully electric vessels capable of handling longer distances and larger loads without compromising on performance or sustainability [19]. In the short term, hybrid vessels serve as a practical bridge between conventional and fully electric maritime transport, enabling industries to reduce emissions and fuel consumption without sacrificing operational reliability [20]. This approach paves the way for future advancements in electric vessel technology, allowing the maritime industry to progressively move toward a cleaner and more sustainable future [21]. Unlike many existing reviews that focus solely on battery chemistries or energy management algorithms, this manuscript offers a comprehensive systems-level review of maritime electrification. It integrates various aspects, including propulsion types, charging infrastructure, medium-voltage direct current (MVDC) grid systems, energy management systems (EMSs), battery management systems (BMSs), and artificial intelligence (AI) applications. Such cross-disciplinary integration is uncommon in the literature and significantly enhances the practical value of the review for designers, policymakers, and shipbuilders. The manuscript adopts a maritime-vessel-centric approach, structuring its discussion around the operational needs and systems of real-world vessels, such as hybrid versus electric propulsion, EMS/BMS functions, charging strategies, and case studies of maritime technologies. A particularly novel aspect is the in-depth examination of AI, machine learning (ML), and deep learning (DL) applications within EMS and BMS frameworks, specifically designed for naval environments, an area typically limited to land-based vehicles or grid applications in existing literature. Furthermore, the review incorporates real-world maritime projects--such as Ellen, Ampere, MF Tycho, Sea Change, Yara Birkeland, and the e5 Project--supported by comparative tables detailing vessel characteristics and battery configurations, thereby providing empirical context often absent in theory-heavy reviews.