• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.367-378
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• 2021

This paper develops a dynamic regression model to quantify the contribution of key external factors to operational energy efficiency of ships. On this basis, kernel density estimation is applied to explore distribution patterns of fluctuations in operational performance. An empirical analysis based on these methods show that distribution of fluctuations in Energy Efficiency Operational Indicator (EEOI) is leptokurtic and fat tailed, rather than a normal one. Around 85% of fluctuations in EEOI can be jointly explained by capacity utilization and sailing speed, while the rest depend on other external factors largely beyond control. The variations in capacity utilization and sailing speed cannot be fully passed on to the energy efficiency performance of ships, due to complex interactions between various external factors. The application of the methods is demonstrated, showing a potential approach to develop a rating mechanism for use in the legally binding framework on operational energy efficiency of ships.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.440-454
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• 2020

To prevent pollution from ships, the Energy Efficiency Design Index (EEDI) is a mandatory guideline for all new ships. The Ship Energy Efficiency Management Plan (SEEMP) has also been applied by MARPOL to all existing ships. SEEMP provides the Energy Efficiency Operational Indicator (EEOI) for monitoring the operational efficiency of a ship. By monitoring the EEOI, the shipowner or operator can establish strategic plans, such as routing, hull cleaning, decommissioning, new building, etc. The key parameter in calculating EEOI is Fuel Oil Consumption (FOC). It can be measured on board while a ship is operating. This means that only the shipowner or operator can calculate the EEOI of their own ships. If the EEOI can be calculated without the actual FOC, however, then the other stakeholders, such as the shipbuilding company and Class, or others who don't have the measured FOC, can check how efficiently their ships are operating compared to other ships. In this study, we propose a method to estimate the EEOI without requiring the actual FOC. The Automatic Identification System (AIS) data, ship static data, and environment data that can be publicly obtained are used to calculate the EEOI. Since the public data are of large capacity, big data technologies, specifically Hadoop and Spark, are used. We verify the proposed method using actual data, and the result shows that the proposed method can estimate EEOI from public data without actual FOC.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.1
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• pp.65-71
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• 2011

Since 2003, policies and practices related to the reduction of CO₂ gas emission from ships has been discussing by the International Maritime Organization. The representative emission index and indicator are the EEDI (Energy Efficiency Design Index) for the new ships and EEOI (Energy Efficiency Operational Indicator) during the voyage. For the CO₂ emission monitoring system, the SEEMP (Ship Energy Efficiency Management Plan) is also on the table. This global preparations to reduce theCO₂ emission is not except for the surface transportation. This research report elucidates the recent stream on the IMO CO₂ emission from ship and detail explanation on the EEDI and EEOI.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1035-1040
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• 2011

In this study, many researches have been carried out against Energy Efficiency Operational Indicator(EEOI) of existing ships under discussion by IMO. This research is examined the method for the polices about IMO's greenhouse gas reducing emissions among them, we were analyzed the EEOI for existing ships. we have analyzed the result about applying EEOI using the calculation method of the rate of fuel consumption for cargo quantities to the actual existing ships and raised the problem. Based on this research, we were presented the improved EEOI about the engine load using fuel consumption and applied the existing ships. As a result, we concluded that the improved EEOI can define a resonable rate of $CO_2$ emissions.

• Journal of Navigation and Port Research
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• v.40 no.4
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• pp.165-171
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• 2016

SEEMP (Ship Energy Efficiency Management Plan) has entered into force since 2013 for the reduction of GHG emission of operating ships. SEEMP guidelines include the hardware modification or installation of energy-saving device on ship. It also includes software based energy-saving technology such as optimum routing, speed optimization, etc. Hardware based technologies are not easy to apply to ongoing vessel due to the operational restriction. Therefore, IT based energy-saving technology was applied and its energy efficiency was evaluated using before and after energy-saving system applied voyage data. SEEMP advises a voluntary participation of EEOI (Ship Energy Efficiency Operation Indicator) use as an indicator of ship energy efficiency operation, and those results were also shown to evaluate the improvement efficiency of energy-saving system.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.981-986
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• 2015

As the seriousness of global environment pollution is gaining increasing public attention, research into greenhouse gas emissions of ships is being carried out globally. At a domestic level, however, in a number of significant fields such research has not been conducted to date. This study examined countermeasures for the reduction of $CO_2$ emission in the fields of electronic control engines, trim optimization, propeller polishing, hull cleaning, and anti-fouling paint using an actual sea-going vessel. Selected countermeasures were applied during sea trials of the ship and the effect of specific fuel oil consumption analyzed. It was found that each countermeasure resulted in a decrease of fuel consumption of 1~5%. The energy efficiency operational indicator (EEOI) was calculated and found to also be improved by 1~5%. Further research into the EEOI of domestic shipping is planned to enhance conformance with international environmental regulations and improve global competitiveness.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.15-20
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• 2017

The International Maritime Organization(IMO) has adopted and implemented compulsory regulation for reducing greenhouse gas emission that cause global warming. However, with global warming underway, the IMO plans to enforce voluntary carbon dioxide emissions reduction based on the Ship Energy Efficient Management Plan and the Energy Efficiency Operational Indicator(EEOI) in the near future. Large container ships sail at low speeds in order to save fuel and reduce carbon dioxide emissions. However, bulbous bows designed for high-speed ships decrease fuel efficiency by acting as resistance when reduced speeds are adopted by large container ships. In order to adopt low-speed operations and increase fuel savings, the bulbous bow of a large container ship was modified into the proper shape and size. Fuel consumption was compared for checking the result of EEOI before and after modifying the bulbous bow adopted on low speed operation of large high-speed ships. The results confirmed much larger carbon dioxide emissions reduction than expected. If EEOI would be implemented as compulsory regulation for reducing carbon dioxide emissions, bulbous bow modification can be considered as one of the fuel saving methods for the high-speed ships.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.6
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• pp.471-477
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• 2015

When a ship sails in a seaway, the resistance on a ship increases due to incident waves and winds. The magnitude of added resistance amounts to about 15–30% of a calm-water resistance. An accurate prediction of added resistance in waves, therefore, is essential to evaluate the performance of a ship in a real sea state and to design an optimum hull form from the viewpoint of the International Maritime Organization (IMO) regulations such as Energy Efficiency Design Index (EEDI) and Energy Efficiency Operational Indicator (EEOI). The present study considers added resistance problem of AFRAMAX-class tankers with the conventional bow and Ax-bow shapes. Added resistance due to waves is successfully calculated using 1) a three-dimensional time-domain seakeeping computations based on a Rankine panel method (three-dimensional panel) and 2) a commercial CFD program (STAR-CCM+). In the hydrodynamic computations of a three-dimensional panel method, geometric nonlinearity is accounted for in Froude-Krylov and restoring forces using simple wave corrections over exact wet hull surface of the tankers. Furthermore, a CFD program is applied by performing fully nonlinear computation without using an analytical formula for added resistance or empirical values for the viscous effect. Numerical computations are validated through four degree-of-freedom model-scale seakeeping experiments in regular head waves at the deep towing tank of Hyundai Heavy Industries.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.198-200
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• 2013

최근 국제해사기구(IMO)의 해양환경보호위원회에서(MEPC)는 선박에서 대기로 방출되는 CO2의 양을 최소로 하기 위해서 신조선 설계 건조시 에너지효율지수(EEDI : Energy Efficiency Design Index for new ships), 에너지 효율지표(EEOI : Energy Efficiency Operational Indicator), 그리고 에너지 효율관리 계획(SEEMP : Ship Energy Efficiency Management Plan) 지수들을 이용하여 전 세계 이산화탄소 배출 규제 방침을 운영하고 있다. 이러한 환경규제 강화와 발맞추어 세계 각국은 지속적인 Green-ship의 개발과 저탄소 고효율 선박의 운항을 위해 연구와 노력한다. 본 연구에서는 선박이 움직이는데 있어 동력이 시작되는 부분과 그 힘이 전달되어 운항자의 의식이 반영되어 선체의 이동으로 이어지기까지 흐름에 대해 도식 및 수식으로 정리하였다. 그리하여 해상의 상태와 이에 따른 운항결정이 어떤 결과를 초래할 수 있는지 살펴보고 이 부분에서 운항효율을 증대시킬 수 있는 부분에 대해 모색해 보았다. 또한 엔진의 상태에 따른 연료 절감율에 대해 살펴보고 보다 경제적 운항을 위한 적정 RPM과 속도 등에 대해서 고찰해 보았다. 이 같은 정리를 통해 앞으로의 Echo-ship, Green-ship의 연구방향에 대한 초석으로 삼고자 한다.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.2
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• pp.132-142
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• 2017

As the International Maritime Organization (IMO) recently introduced the Energy Efficiency Design Index (EEDI) for new ships building and the Energy Efficiency Operational Indicator (EEOI) for ship operation, thus an accurate estimation of added resistance of ships advancing in waves has become necessary. In the present study, OpenFOAM, computational fluid dynamics libraries of which source codes are opened to the public, was used to calculate the added resistance and motions of the KCS. Unstructured grid using a hanging-node and cut-cell method was used to generate dense grid around a wave and KCS. A dynamic deformation mesh method was used to consider the motions of the KCS. Five wavelengths from a short wavelength (${\lambda}/LPP=0.65$) to a long wavelength (${\lambda}/LPP=1.95$) were considered. The added resistance and the heave & pitch motions calculated for various waves were compared with the results of model experiments.