Emissions from vessels are a major environmental concern because of their impacts on the deterioration of the environment, especially global warming of the atmosphere. Therefore, the International Maritime Organization (IMO) concern significant care to environmental protection through the reduction of exhaust emission and improvement of energy efficiency through technical and operational measures. Among the suggested measures from IMO, the alternative fuel such as Liquefied Natural Gas (LNG) has the priority to be used instead of fossil fuels. The present paper calculates the effect of using LNG in a dual fuel engine from Environmental and Energy efficiency perspectives. As a case study, a Container Ship has been investigated. The results of the analysis show that percent of CO 2 , NOx and SOx emissions reduction corresponding to using a dual-fuel engine operating by LNG instead of a diesel engine operating by Heavy Fuel Oil is about 30.1%,81.44%, and 96.94%, respectively. Also, the attained Energy Efficiency Index Value in the case of using the dual-fuel engine is lower than its value by using diesel engine by about 30% and this value will be 77.18%, 86.84%, and 99.27% of the required value of the first, second and third phases, respectively as recommended by IMO.
Greenhouse gases and other emissions from vessels and related activities in maritime trade have caused significant environmental impacts especially global warming of the atmosphere. Consequently, the International Maritime Organization (IMO) concern significant care to the reduction of ship emissions and improvement of energy efficiency through operational and technical measures. The proposed short-term measure is ship speed reduction in which the ship speed is reduced below its designed value. Therefore, the present paper aims at evaluating the potential energy efficiency and environmental benefits from using speed reduction measure through energy efficiency design index (EEDI), energy efficiency operational indicator (EEOI) and ship emissions calculation models as recommended from IMO. As a case study, a medium sized Container Ship is investigated. The results show that, reducing ship speed by 12.6% will reduce CO2 emissions by about 36%. Moreover, the attained EEDI value will be improved by 31.7% and comply with not only the current IMO requirements but also with the future ones. Additionally, reducing ship speed by 12.6% will reduce EEOI value from its value at design speed by 26.5%. Furthermore, it is noticed that SOx emission will comply with IMO 2020 limit if ship speed is reduced by 6.8% and above.
The ambitious targets set by the International Maritime Organization for reducing greenhouse gas emissions from shipping require radical actions by all relevant stakeholders. In this context, the interest in high efficiency and low emissions (even zero in the case of hydrogen) fuel cell technology for maritime applications has been rising during the last decade, pushing the research developed by academia and industries. This paper aims to present a comparative review of the fuel cell systems suitable for the maritime field, focusing on PEMFC and SOFC technologies. This choice is due to the spread of these fuel cell types concerning the other ones in the maritime field. The following issues are analyzed in detail: (i) the main characteristics of fuel cell systems; (ii) the available technology suppliers; (iii) international policies for fuel cells onboard ships; (iv) past and ongoing projects at the international level that aim to assess fuel cell applications in the maritime industry; (v) the possibility to apply fuel cell systems on different ship types. This review aims to be a reference and a guide to state both the limitations and the developing potential of fuel cell systems for different maritime applications.
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