A Preliminary Study on an Alternative Ship Propulsion System Fueled by Ammonia: Environmental and Economic Assessments

Abstract

The shipping industry is becoming increasingly aware of its environmental responsibilities in the long-term. In 2018, the International Maritime Organization (IMO) pledged to reduce greenhouse gas (GHG) emissions by at least 50% by the year 2050 as compared with a baseline value from 2008. Ammonia has been regarded as one of the potential carbon-free fuels for ships based on these environmental issues. In this paper, we propose four propulsion systems for a 2500 Twenty-foot Equivalent Unit (TEU) container feeder ship. All of the proposed systems are fueled by ammonia; however, different power systems are used: main engine, generators, polymer electrolyte membrane fuel cell (PEMFC), and solid oxide fuel cell (SOFC). Further, these systems are compared to the conventional main engine propulsion system that is fueled by heavy fuel oil, with a focus on the economic and environmental perspectives. By comparing the conventional and proposed systems, it is shown that ammonia can be a carbon-free fuel for ships. Moreover, among the proposed systems, the SOFC power system is the most eco-friendly alternative (up to 92.1%), even though it requires a high lifecycle cost than the others. Although this study has some limitations and assumptions, the results indicate a meaningful approach toward solving GHG problems in the maritime industry.

Review on Ammonia as a Potential Fuel: From Synthesis to Economics

“…Kim et al carried out a detailed feasibility study on the use of ammonia for a ship propulsion system. 424 Their work considered four different ammonia-fueled propulsion systems for a container feeder ship. These systems were compared (economically and environmentally) to a conventional heavy fuel oil fuel propulsion system.…”

Review on the Safe Use of Ammonia Fuel Cells in the Maritime Industry

“…In the existing literature there has been great attention on potential catalysts for the ammonia oxidation [62][63][64][65] and specifically for SOFCs [66,67]. The performance of ammonia fuel cell for land-based energy production or for other systems has attracted attention in the literature, as presented in Table 3.…”

Hydrogen application technologies and environmentally friendly smart energy system

“…Hiệu suất của quá trình đốt ammonia nguyên chất còn thấp nhưng việc trộn ammonia với các nhiên liệu khác (như hydrogen) có thể giúp khắc phục đặc tính bất lợi khó cháy và cải thiện hiệu suất [18, 21,22]. Động cơ đốt nhiên liệu kép (ammonia-hydrogen) sẽ là hướng đi khả thi nhất để ammonia thâm nhập vào lĩnh vực hàng hải.…”