## 1 Introduction  
Maritime transportation is the primary means of transport and is responsible for over 80% of the world's trade by volume [1]. Thus, it is also a major source of climate change and air pollution, which negatively impacts health and the environment [2]. In response to this issue, the International Maritime Organization (IMO) has adopted various regulations and mandatory measures to avoid further negative impacts on the environment, control airborne emissions, and decrease greenhouse gases (GHGs). The IMO 2020 lowered the limit of the sulfur content of ship fuel from 3.5% in 2015 to 0.5% [3], and the IMO GHG initial strategy also agreed to reduce carbon dioxide (CO\({}_{2}\)) emissions per transportation by at least 40% by 2030 and total yearly GHG emissions by no less than 50% by 2050 in comparison with 2008 [4, 5]. These strategies and targets have driven global maritime shipping to new technologies, renewable energy, and alternative fuel sources with low- or decarbonization. Recently, ammonia has emerged as a promising and potential marine fuel for avoiding CO\({}_{2}\) emissions, resulting in low climate impacts and a clean future [6]. Ammonia (NH\({}_{3}\)) is a carbon-free compound and one of the intermediate products in various industrial applications [7, 8]. NH\({}_{3}\) can be widely produced by well-established methods and infrastructures such as the Haber-Bosch process, the electrochemical process,and power-to-gas technologies or produced from algae through a hydrothermal gasification combined system [9]. This fuel can be easily stored, either refrigerated at \(-33\)\({}^{\circ}\)C and atmospheric pressure or approximately \(29.5\)\({}^{\circ}\)C and pressurized to \(800\)-\(1000\) kPa [6; 7; 10; 11]. In addition, since NH\({}_{3}\) contains a \(45\%\) higher volumetric hydrogen density than liquid hydrogen, it is also a potentially attractive medium for hydrogen storage. When the end-user requires hydrogen as a fuel for a specific application, ammonia can be converted to hydrogen using a very low amount of energy for the reforming process [7]. Thus, ammonia can be utilized for energy purposes in several maritime applications, such as fuel cells and internal combustion engines [7]. [PERSON] et al. [12] performed the comprehensive review on ammonia in terms of production, storage and applications, and proved that ammonia is a strong candidate for use as a hydrogen carrier in the future and direct ammonia fuel cells are promising in terms of total energy efficiency. Ammonia linked to fuel cells is currently being studied by researchers and manufacturers owing to its advantages over internal combustion engines, as they provide high efficiency, less noise, lower emissions of air pollutants, and higher thermal efficiencies. Depending on the working temperature of the fuel cells, ammonia can be used directly or indirectly by a reformer (that splits ammonia into H\({}_{2}\) and N\({}_{2}\) before supplying to the fuel cells). The two typical types of fuel cells that can be used with ammonia systems are solid oxide fuel cells (SOFCs) and proton-exchange membrane fuel cells (PEMFCs). Other types of fuel cells, such as alkaline and alkaline membranes, are under development, and few experimental reports are available [5]. SOFCs use ammonia directly [13; 14], whereas PEMFCs require purified hydrogen (indirectly using ammonia by reforming). Focusing on the future of electric propulsion vessels, SOFCs, which consume ammonia directly for electric power and obtain reasonable energy efficiencies, possess great potential [15; 16; 17]. [PERSON] et al. [18] assessed the working performance of direct ammonia fuel cells and showed that an increase in electrolyte thickness decreases cell performance significantly. Thus, high-performance SOFCs can be obtained using low thickness, high temperatures, and electrolytes. [PERSON] et al. [19] developed a combined system of SOFCs and gas turbines using ammonia as fuel and evaluated the proposed system using the first and second laws of thermodynamics.