Abstract: Due to the development of distributed generation (DG) and power management technologies, an islanded marine power system, namely microgrid in marine, becomes a promising option for marine power systems and gains an increase in research interest. Microgrid solution provides integration of renewables, energy storage systems and existing generation units. It enhances energy efficiency, reduces CO2 emissions, and improves dynamic responding to load fluctuations. In this way, the overall performance of vessel information and control system is optimized. The goal of this thesis is to investigate the feasibility of operating microgrids in marine vessels. Power management strategies are formulated with integration of energy storage and renewable sources, like photovoltaics (PV), to the existing diesel generators within a small-islanded network. Before the system level analysis, modeling of the energy resources, energy storage, and power electronic converters is obtained. In order to weigh the benefits and assess the potentials of implementing the shipboard DC microgrid system, this work facilitates a detailed MATLAB simulation-based study accounting for the factors of realistic vessel operation load profiles, stability and reliability of DC microgrids. Chapter 1 and 2 provide the introduction and prior art from industrial solutions and academic research. The prior art covers shipboard power network structure, load profile requirement, energy storage system (ESS), power management system (PMS), and academic research methodologies of the marine vessels. Chapter 3 analyzes the feasibility of implementing a marine microgrid based on ABB solutions of land-based microgrids. An integration of the inland microgrid solutions to the existing marine automation and control platform is proposed. After that, the integrated functions of the proposed marine microgrid are formulated in Chapter 4. The system configuration and the microgrid PMS for marine applications are developed. Control and energy storage functions and stability of operating the proposed shipboard microgrid system (SMS) are verified in Chapter 5 by testing four specific scenarios. The simulation results show that the SMS works in stable operational modes under various loading conditions. Additionally, with proper power management strategies chosen for different operation modes, the operating of SMS can be shifted between different states without significant impacts on the power quality and stability of the system.