As climate change concerns increase, the maritime industry faces an urgent need to reduce emissions and adopt sustainable practices. The integration of hybrid systems, particularly those incorporating Battery Energy Storage Systems (BESS), has emerged as a promising solution to enhance energy effi- ciency and lower the environmental impact. This Master Thesis focuses on developing a methodology for determining the most suitable battery size and type for existing vessels to be hybridized, balancing effectiveness and cost-efficiency. This thesis was conducted in collaboration with Jan De Nul Group, a leading global firm in environmental services, engineering, marine construction, and dredging.

The primary goal of this research is to design a methodology that compares different control strate- gies for sizing battery systems and selecting appropriate chemistries. A case study based on a trailing suction hopper dredger vessel was explored.

Three control strategies were evaluated using numerical modeling: optimal operation of the current scenario without batteries, load smoothing using a moving average approach, and optimal range op- eration of generators. To optimise the number of running generators and reduce maintenance costs, an automatic start-stop logic is implemented as a model initialisation. The optimal operation of the current scenario without batteries highlights the need for battery integration to compensate for the high supply deficit. In addition, the load smoothing strategy creates a more stable demand curve, allowing generators to operate more efficiently, while the optimal range strategy keeps generators near their rated power, maximizing efficiency and minimizing fuel consumption.

The study assesses battery performance under two scenarios: continuous full cycling throughout the year and calendar aging specifically during harbour operations. Battery power is calculated based on demand and generator output, considering state-of-charge constraints. Three types of lithium-ion batteries were evaluated for their suitability in ocean-going hybrid vessels: Lithium Nickel Cobalt Manganese Oxide (NMC), Lithium Iron Phosphate (LFP), and Lithium Titanate Oxide (LTO).

A total of 648 battery solutions under the load smoothing strategy and 216 under the optimal range strategy were assessed. Using four key criteria, the selection of battery options was narrowed down. Given the limitations of the model used in this research, findings suggest that batteries affected primar- ily by calendar aging have shorter lifespans, making cycling behavior preferable for achieving longer battery lifetime and higher Return On Investment (ROI). The optimal range strategy leads to higher fuel savings compared to load smoothing, while load smoothing results in a longer battery lifespan due to fewer equivalent cycles. In summary, selecting the best battery solution hinges on whether the priority is immediate ROI or long-term operational efficiency. This thesis offers a comprehensive methodology for integrating BESS, contributing valuable insights to the advancement of sustainable energy solutions in the maritime sector.