**Gilltae Roh 1, Hansung Kim 1, Hyeonmin Jeon <sup>2</sup> and Kyoungkuk Yoon 3,\***


Received: 17 May 2019; Accepted: 15 July 2019; Published: 18 July 2019

**Abstract:** The need for technological development to reduce the impact of air pollution caused by ships has been strongly emphasized by many authorities, including the International Maritime Organization (IMO). This has encouraged research to develop an electric propulsion system using hydrogen fuel with the aim of reducing emissions from ships. This paper describes the test bed we constructed to compare our electric propulsion system with existing power sources. Our system uses hybrid power and a diesel engine generator with a combined capacity of 180 kW. To utilize scale-down methodology, the linear interpolation method is applied. The proposed hybrid power source consists of a molten carbonate fuel cell (MCFC), a battery, and a diesel generator, the capacities of which are 100 kW, 30 Kw, and 50 kW, respectively. The experiments we conducted on the test bed were based on the outcome of an analysis of the electrical power consumed in each operating mode considering different types of merchant ships employed in practice. The output, fuel consumption, and CO2 emission reduction rates of the hybrid and conventional power sources were compared based on the load scenarios created for each type of ship. The CO2 emissions of the hybrid system was compared with the case of the diesel generator alone operation for each load scenario, with an average of 70%~74%. This analysis confirmed the effectiveness of using a ship with a fuel-cell-based hybrid power source.

**Keywords:** hybrid power source; fuel cell; molten carbonate fuel cell (MCFC); carbon dioxide; electric propulsion system
