The IMO (International Maritime Organization) has mandated the restriction of SOx emissions to 0.5 % for all international sailing vessels since January 2020. And, a number of countries have designated emission control areas for stricter environmental regulations. Three representative methods have been suggested to cope with these regulations; using low-sulphur oil, installing a scrubber, or using LNG (Liquefied Natural Gas) as fuel. In this paper, economic analysis was performed by comparing the method of installing a scrubber with the method of using low-sulphur oil without installing additional equipment. We suggested plausible layouts and compared the pros and cons of different scrubber types for retrofitting. We selected an international sailing ship as the target vessel and estimated payback time and benefits based on navigation route, fuel consumption, and installation and operation costs. Two case of oil prices were analyzed considering the uncertainty of fuel oil price fluctuation. We found that the expected payback time of investment varies from 1 year to 3.5 years depending on the operation ratio of emission control areas and the fuel oil price change.

Abstract
1. Introduction
2. Methods of SOx regulation response for ships
    2.1 Use of low-sulphur oil
    2.2 Installation of a SOx scrubber
    2.3 Installation of LNG fuel supply system
3. Economic analysis of SOx scrubber
    3.1 Target Ship
    3.2 Voyage route
    3.3 Calculation of target vessel fuel oil consumption
    3.4 Fuel oil according to area and time
    3.5 CAPEX (Capital Expenditure) for SOx scrubber installation
    3.6 OPEX (Operating Expenditure) for SOx scrubber
    3.7 Fuel oil price
4. Results and discussion
5. Conclusion
References

• Jae-hoon Jee(Mokpo National Maritime University)