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22 pages, 6142 KiB

Open AccessArticle

Eco-Friendly Speed Control Algorithm Development for Autonomous Vessel Route Planning

by Sewon Kim, Sangwoong Yun and Youngjun You

J. Mar. Sci. Eng. 2021, 9(6), 583; https://doi.org/10.3390/jmse9060583 - 28 May 2021

Cited by 7 | Viewed by 2858

Abstract

The upcoming autonomous vessel voyage is promising future in the maritime sector. However, so far, the contemporary route decision making technologies rely on human intervention. Therefore, this manuscript proposes the two newly developed speed algorithms: the modified fixed speed control and the wave [...] Read more.

The upcoming autonomous vessel voyage is promising future in the maritime sector. However, so far, the contemporary route decision making technologies rely on human intervention. Therefore, this manuscript proposes the two newly developed speed algorithms: the modified fixed speed control and the wave feed forward speed control in the route decision making procedure for the autonomous vessels. These two algorithms can control the vessel’s speed without human intervention in eco-friendly and economic manner. The first algorithm is the wave feed forward speed control that can predict the speed change according to wave loads and compensate it to reduce the fluctuation of speed, power, and fuel consumption. To develop this algorithm, the real time modeling of the wave added resistance and the wave real time effect on propulsion are analyzed. The efficacy of the developed wave feed forward scheme is validated using the in-house route optimization simulation program through comparisons with the results of conventional speed governor control case. The developed schemes are applied to a 173 K LNG (Liquefied Natural Gas) carrier with twin propulsion. The other proposed speed control algorithm is the modified fixed control algorithm. This algorithm improves the conventional fixed power control algorithm by adding a time marching module to satisfy the required time arrival of the voyage. The two proposed methods are analyzed in the various simulations—ideal environmental conditions and real voyage environments: The Pacific and the Atlantic cases. Based on the results, the suggested methods can reduce fuel oil consumption, gas emission, and wear and tear problem of the propulsion devise of ship. In the study, it is clearly demonstrated that the developed wave feed forward speed control and modified fixed power scheme perform much better than the conventional speed governor control case. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection)

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16 pages, 2461 KiB

Open AccessArticle

Effects of a Vessel Speed Reduction Program on Air Quality in Port Areas: Focusing on the Big Three Ports in South Korea

by Jiyoung An, Kiyoul Lee and Heedae Park

J. Mar. Sci. Eng. 2021, 9(4), 407; https://doi.org/10.3390/jmse9040407 - 11 Apr 2021

Cited by 10 | Viewed by 2801

Abstract

As the seriousness of air pollution from ports and ships is recognized, the Korean Port Authority is implementing many policies and instruments to reduce air pollution in port areas. This study aims to verify the effects of the vessel speed reduction (VSR) program [...] Read more.

As the seriousness of air pollution from ports and ships is recognized, the Korean Port Authority is implementing many policies and instruments to reduce air pollution in port areas. This study aims to verify the effects of the vessel speed reduction (VSR) program among the procedures related to air pollution in port areas. This study was conducted using panel data created by combining ship entry and departure data and air quality measurement data. We measured the changes in air quality according to the entry and departure of ships and examined whether it changes due to the VSR program. For estimation, the panel fixed-effect model and the ordinary least squares (OLS) model were used. The results suggest that the VSR program had a positive effect on improving air quality in port areas. However, the VSR program’s effects were different over ports. Busan Port showed the highest policy effect, and Incheon Port showed a relatively low policy effect. Based on the results of this study, to maximize the VSR program’s effectiveness at the port, it is necessary to implement other eco-friendly policies as well. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection)

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20 pages, 2710 KiB

Open AccessArticle

Comparison of the Economic Performances of Three Sulphur Oxides Emissions Abatement Solutions for a Very Large Crude Carrier (VLCC)

by Hongjun Fan, Huan Tu, Hossein Enshaei, Xiangyang Xu and Ying Wei

J. Mar. Sci. Eng. 2021, 9(2), 221; https://doi.org/10.3390/jmse9020221 - 19 Feb 2021

Cited by 13 | Viewed by 3542

Abstract

Ship-source air pollutants, especially sulphur oxides (SOx), have a major impact on human health, the marine environment and the natural resources. Therefore, control of SOx emissions has become a main concern in the maritime industry. The International Maritime Organization (IMO) has set a [...] Read more.

Ship-source air pollutants, especially sulphur oxides (SOx), have a major impact on human health, the marine environment and the natural resources. Therefore, control of SOx emissions has become a main concern in the maritime industry. The International Maritime Organization (IMO) has set a global limit on sulphur content of 0.50% m/m (mass by mass) in marine fuels which has entered into effect on 1 January 2020.To comply with the sulphur limits, ship owners are facing the need to select suitable abatement solutions. The choice of a suitable solution is a compromise among many issues, but the economic performance offers the basis for which ones are attractive to ship owners. Currently, there are three technologically feasible SOx abatement solutions that could be used by ships, namely, liquified natural gas (LNG) as a fuel (Solution A), scrubbers (Solution B) and low-sulphur fuel oil (LSFO) (Solution C). To compare the economic performances of the mentioned three solutions for a newbuilding very large crude carrier (VLCC), this paper proposes a voyage expenses-based method (VEM). It was found that, within the initial target payback period of 6 years, Solution A and C are more expensive than Solution B, while Solution C is more competitive than Solution A. Five scenarios of target payback years were assumed to compare the trends of the three proposed solutions. The results show that Solution B maintains its comparative advantage. As the assumed target payback years becomes longer, the economy of Solution A gradually improves and the economics of Solution B and C gradually decline. A comparison between Solution A and C shows 6.5 years is a turning point. The advantage of Solution A is prominent after this payback period. In addition, the performance of a certain solution in terms of adaptability to the IMO greenhouse gas (GHG) emissions regulations is also a factor that ship owner need to consider when making decisions. In conclusion, when the IMO air pollutant regulations and GHG regulations are considered simultaneously, the advantages of using LNG are obvious. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection)

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19 pages, 30649 KiB

Open AccessArticle

Investigation of Effect on Environmental Performance of Using LNG as Fuel for Engines in Seaport Tugboats

by Sergejus Lebedevas, Lukas Norkevičius and Peilin Zhou

J. Mar. Sci. Eng. 2021, 9(2), 123; https://doi.org/10.3390/jmse9020123 - 27 Jan 2021

Cited by 13 | Viewed by 3315

Abstract

Decarbonization of ship power plants and reduction of harmful emissions has become a priority in the technological development of maritime transport, including ships operating in seaports. Engines fueled by diesel without using secondary emission reduction technologies cannot meet MARPOL 73/78 Tier III regulations. [...] Read more.

Decarbonization of ship power plants and reduction of harmful emissions has become a priority in the technological development of maritime transport, including ships operating in seaports. Engines fueled by diesel without using secondary emission reduction technologies cannot meet MARPOL 73/78 Tier III regulations. The MEPC.203 (62) EEDI directive of the IMO also stipulates a standard for CO₂ emissions. This study presents the results of research on ecological parameters when a CAT 3516C diesel engine is replaced by a dual-fuel (diesel-liquefied natural gas) powered Wartsila 9L20DF engine on an existing seaport tugboat. CO₂, SO₂ and NO_x emission reductions were estimated using data from the actual engine load cycle, the fuel consumption of the KLASCO-3 tugboat, and engine-prototype experimental data. Emission analysis was performed to verify the efficiency of the dual-fuel engine in reducing CO₂, SO₂ and NO_x emissions of seaport tugboats. The study found that replacing a diesel engine with a dual-fuel-powered engine led to a reduction in annual emissions of 10% for CO₂, 91% for SO₂, and 65% for NO_x. Based on today’s fuel price market data an economic impact assessment was conducted based on the estimated annual fuel consumption of the existing KLASCO-3 seaport tugboat when a diesel-powered engine is replaced by a dual-fuel (diesel-natural gas)-powered engine. The study showed that a 33% fuel costs savings can be achieved each year. Based on the approved methodology, an ecological impact assessment was conducted for the entire fleet of tugboats operating in the Baltic Sea ports if the fuel type was changed from diesel to natural gas. The results of the assessment showed that replacing diesel fuel with natural gas achieved 78% environmental impact in terms of NO_x emissions according to MARPOL 73/78 Tier III regulations. The research concludes that new-generation engines on the market powered by environmentally friendly fuels such as LNG can modernise a large number of existing seaport tugboats, significantly reducing their emissions in ECA regions such as the Baltic Sea. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection)

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21 pages, 1267 KiB

Open AccessArticle

Investment Analysis of Waste Heat Recovery System Installations on Ships’ Engines

by Eunice O. Olaniyi and Gunnar Prause

J. Mar. Sci. Eng. 2020, 8(10), 811; https://doi.org/10.3390/jmse8100811 - 19 Oct 2020

Cited by 17 | Viewed by 4852

Abstract

This study considers incentive provisions for investment decisions related to waste heat recovery system (WHRS) installations on ships to reduce CO₂ emissions and improve ships’ engine efficiency. The economic assessment of WHRS installations in the shipping sector is not widely covered in [...] Read more.

This study considers incentive provisions for investment decisions related to waste heat recovery system (WHRS) installations on ships to reduce CO₂ emissions and improve ships’ engine efficiency. The economic assessment of WHRS installations in the shipping sector is not widely covered in the literature. A reason for this might be that the conventional financial evaluation of sensitive choices is commonly done through capital budgeting methods, which are not flexible enough to integrate future changes in fuel prices and long-term aspects of other costs. Thus, this work evaluates the WHRS investment using the classical budgeting instruments as well as the real-options approach (a more sophisticated approach) to accommodate the presumed expected future changes in the volatile maritime markets. Following the methodology of triangulation, three case studies of ships with varying operational conditions empirically validate the result to depict the practical use of the real-options evaluation method in investment assessment. The capital budgeting analysis reveals that the investment in maritime WHRS technology is only economically favorable under certain frame conditions projected in the work that shows a more realistic assessment of the project. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection)

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22 pages, 4696 KiB

Open AccessArticle

Application of Reference Voltage Control Method of the Generator Using a Neural Network in Variable Speed Synchronous Generation System of DC Distribution for Ships

by Hyeonmin Jeon and Jongsu Kim

J. Mar. Sci. Eng. 2020, 8(10), 802; https://doi.org/10.3390/jmse8100802 - 15 Oct 2020

Cited by 4 | Viewed by 2733

Abstract

In the case of DC power distribution-based variable speed engine synchronous generators, if the output reference voltage is kept constant regardless of the generator engine operating speed, it may cause damage to the internal device and windings of the generator due to over-flux [...] Read more.

In the case of DC power distribution-based variable speed engine synchronous generators, if the output reference voltage is kept constant regardless of the generator engine operating speed, it may cause damage to the internal device and windings of the generator due to over-flux or over-excitation. The purpose of this study is to adjust the generator reference voltage according to the engine speed change in the DC distribution system with the variable speed engine synchronous generator. A method of controlling the generator reference voltage according to the speed was applied by adjusting the value of the variable resistance input to the external terminal of the automatic voltage regulator using a neural network controller. The learning data of the neural network was measured through an experiment, and the input pattern was set as the rotational speed of the generator engine, and the output pattern was set as the input current of the potentiometer. Using the measured input/output pattern of the neural network, the error backpropagation learning algorithm was applied to derive the optimum connection weight to be applied to the controller. For the test, the variable speed operation range of the generator engine was set to 1100–1800 rpm, and the input current value of the potentiometer according to the speed increase or decrease within the operation range and the output of the voltage output from the actual generator were checked. As a result of neural network control, it was possible to confirm the result that the input current value of the potentiometer accurately reached the target value 4–20 mA at the point where the initial speed change occurred. It was confirmed that the reference voltage was also normally output in the target range of 250–440 V. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection)

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13 pages, 3059 KiB

Open AccessArticle

Characterization of Biomethanol–Biodiesel–Diesel Blends as Alternative Fuel for Marine Applications

by Zhongcheng Wang, Tatjana Paulauskiene, Jochen Uebe and Martynas Bucas

J. Mar. Sci. Eng. 2020, 8(9), 730; https://doi.org/10.3390/jmse8090730 - 22 Sep 2020

Cited by 9 | Viewed by 3022

Abstract

The ambitious new International Maritime Organization (IMO) strategy to reduce greenhouse gas emissions from ships will shape the future path towards the decarbonization of the fleet and will bring further ecological challenges. In order to replace the larger oil-based part of marine fuel [...] Read more.

The ambitious new International Maritime Organization (IMO) strategy to reduce greenhouse gas emissions from ships will shape the future path towards the decarbonization of the fleet and will bring further ecological challenges. In order to replace the larger oil-based part of marine fuel with components from renewable sources, it is necessary to develop multi-component blends. In this work, biomethanol and biodiesel with two additives—dodecanol and 2-ethylhexyl nitrate—in 20 blends with marine diesel oil (MDO) were selected as alternative components to replace the pure marine diesel oil-based part of marine fuel. For this purpose, two base blends of diesel and biodiesel with and without additives were produced with biomethanol from 0 to 30% (volume basis). Of all the blends, the blends with 5% (volume basis) methanol had the best property profile in terms of density, kinematic viscosity, calorific value, cloud point, and cetane index according to the ISO 8217:2017 standard (DMB grade) in compliance with the IMO requirements for marine fuels. However, the flash point must be increased. The boiling behavior of the blends was also investigated. A cluster analysis was used to evaluate the similarity between the blends based on their different physical properties. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection)

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23 pages, 3796 KiB

Open AccessArticle

Use of LNG Cold Potential in the Cogeneration Cycle of Ship Power Plants

by Zhongcheng Wang, Sergejus Lebedevas, Paulius Rapalis, Justas Zaglinskis, Rima Mickeviciene, Vasilij Djackov and Xiaoyu Liu

J. Mar. Sci. Eng. 2020, 8(9), 720; https://doi.org/10.3390/jmse8090720 - 18 Sep 2020

Cited by 1 | Viewed by 2621

Abstract

This paper presents the results of a numerical study on the parameters that affect the efficiency of the cogeneration cycle of a ship’s power plant. The efficiency was assessed based on the excess power (N_gen.) of a free turbine, operated with [...] Read more.

This paper presents the results of a numerical study on the parameters that affect the efficiency of the cogeneration cycle of a ship’s power plant. The efficiency was assessed based on the excess power (N_gen.) of a free turbine, operated with the inflow of gaseous nitrogen, which was used to generate electricity. A mathematical model and simulation of the regenerative cycle were created and adjusted to operate with a dual-fuel (diesel-liquid natural gas (LNG)) six-cylinder four-stroke engine, where the energy of the exhaust gas was converted into mechanical work of the regenerative cycle turbine. The most significant factors for N_gen. were identified by parametrical analysis of the cogeneration cycle: in the presence of an ‘external’ unlimited cold potential of the LNG, N_gen. determines an exhaust gas temperature Te_g of power plant; the pressure of the turbo unit and nitrogen flow are directly proportional to N_gen. When selecting the technological units for cycle realization, it is rational to use high flow and average

π_{T}

pressure (~3.0–3.5 units) turbo unit with a high adiabatic efficiency turbine. The effect of the selected heat exchangers with an efficiency of 0.9–1.0 on N_gen. did not exceed 10%. With LNG for ‘internal’ use in a ship as a fuel, the lowest possible temperature of N₂ is necessary, because each 10 K increment in N₂ entering the compressor decreases N_gen. by 5–8 kW, i.e., 5–6%. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection)

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18 pages, 2988 KiB

Open AccessArticle

Life Cycle Assessment of Alternative Ship Fuels for Coastal Ferry Operating in Republic of Korea

by Sang Soo Hwang, Sung Jin Gil, Gang Nam Lee, Ji Won Lee, Hyun Park, Kwang Hyo Jung and Sung Bu Suh

J. Mar. Sci. Eng. 2020, 8(9), 660; https://doi.org/10.3390/jmse8090660 - 26 Aug 2020

Cited by 39 | Viewed by 5332

Abstract

In this study, the environmental impacts of various alternative ship fuels for a coastal ferry were assessed by the life cycle assessment (LCA) analysis. The comparative study was performed with marine gas oil (MGO), natural gas, and hydrogen with various energy sources for [...] Read more.

In this study, the environmental impacts of various alternative ship fuels for a coastal ferry were assessed by the life cycle assessment (LCA) analysis. The comparative study was performed with marine gas oil (MGO), natural gas, and hydrogen with various energy sources for a 12,000 gross tonne (GT) coastal ferry operating in the Republic of Korea (ROK). Considering the energy imports of ROK, i.e., MGO from Saudi Arabia and natural gas from Qatar, these countries were chosen to provide the MGO and the natural gas for the LCA. The hydrogen is considered to be produced by steam methane reforming (SMR) from natural gas with hard coal, nuclear energy, renewable energy, and electricity in the ROK model. The lifecycles of the fuels were analyzed in classifications of Well-to- Tank, Tank-to-Wake, and Well-to-Wake phases. The environmental impacts were provided in terms of global warming potential (GWP), acidification potential (AP), photochemical potential (POCP), eutrophication potential (EP), and particulate matter (PM). The results showed that MGO and natural gas cannot be used for ships to meet the International Maritime Organization’s (IMO) 2050 GHG regulation. Moreover, it was pointed out that the energy sources in SMR are important contributing factors to emission levels. The paper concludes with suggestions for a hydrogen application plan for ships from small, nearshore ships in order to truly achieve a ship with zero emissions based on the results of this study. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection)

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27 pages, 12541 KiB

Open AccessArticle

Evaluation of the Lifecycle Environmental Benefits of Full Battery Powered Ships: Comparative Analysis of Marine Diesel and Electricity

by Byongug Jeong, Hyeonmin Jeon, Seongwan Kim, Jongsu Kim and Peilin Zhou

J. Mar. Sci. Eng. 2020, 8(8), 580; https://doi.org/10.3390/jmse8080580 - 02 Aug 2020

Cited by 31 | Viewed by 6033

Abstract

The paper aims to investigate the holistic environmental benefits of using a battery system on a roll on/roll off (ro-ro) passenger ship which was originally fitted with a diesel engine engaged in Korean coastal service. The process of this research has multiple layers. [...] Read more.

The paper aims to investigate the holistic environmental benefits of using a battery system on a roll on/roll off (ro-ro) passenger ship which was originally fitted with a diesel engine engaged in Korean coastal service. The process of this research has multiple layers. First, the operating profiles of the case ship were collected, such as speed, output, operation time and the configuration of the diesel propulsion system. Second, the full battery propulsion system, in place of the diesel system, was modelled and simulated on a power simulation software (PSIM) platform to verify the adequacy of the proposed battery propulsion system. Then, the life cycle assessment method was applied to comprehensively compare the environmental footprint of the diesel-mechanical and fully battery-powered vessels. A focus was placed on the life cycle of the energy sources consumed by the case ship in consideration of the South Korea’s current energy importation and production status. Three life cycle stages were considered in the analysis: ‘production’, ‘transport’ and ‘use’. With the aid of Sphera GaBi Software Version 2019 and its extensive data library, the environmental impacts at the energy production and transport stages were evaluated, while the same impacts at the use stage were determined based on actual laboratory measurements. The environmental performance of the two scenarios in four impact categories was discussed: global warming potential (GWP), acidification potential (AP), eutrophication potential (EP) and photochemical ozone creation potential (POCP). Results of the comparative analysis are presented based on estimates of the overall reduction in the environmental impact potential, thereby demonstrating the overall benefits of using a battery driven propulsion, with a decrease of the GWP by 35.7%, the AP by 77.6%, the EP by 87.8% and the POCP by 77.2%. A series of sensitivity analyses, however, has delivered the important message that the integration of batteries with marine transportation means may not always be the best solution. The types of energy sources used for electricity generation will be a key factor in determining whether the battery technology can ultimately contribute to cleaner shipping or not. By casting doubts on the benefits of battery propulsion, this paper is believed to offer a meaningful insight into developing a proper road map for electrifying ship propulsion toward zero emission of shipping. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection)

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17 pages, 5057 KiB

Open AccessTechnical Note

Comparative Life Cycle Assessment of Marine Insulation Materials

by Hayoung Jang, Yoonwon Jang, Byongug Jeong and Nak-Kyun Cho

J. Mar. Sci. Eng. 2021, 9(10), 1099; https://doi.org/10.3390/jmse9101099 - 09 Oct 2021

Cited by 6 | Viewed by 2388

Abstract

This study aimed to reduce the holistic environmental impacts of insulation materials proposed for the accommodation of a marine cargo ship, and suggest the optimal option for cleaner ship production, using life cycle assessment. With a commercial bulk carrier as a case ship, [...] Read more.

This study aimed to reduce the holistic environmental impacts of insulation materials proposed for the accommodation of a marine cargo ship, and suggest the optimal option for cleaner ship production, using life cycle assessment. With a commercial bulk carrier as a case ship, three major insulations were assessed, which were wool-based material (mineral wool or glass wool), expanded polystyrene, and polyurethane foam. The analysis was scoped based on ‘from cradle to grave’, while focusing on the following five representative environmental indicators: global warming potential_100years, acidification potential, eutrophication potential, ozone depletion potential, and human toxicity potential. The assessment was performed in the platform of the GaBi software. The results showed that polyurethane foam would have the greatest impacts, especially in regard to global warming, eutrophication, and human toxicity. On the other hand, expanded polystyrene and wool-based material showed better environmental performance than polyurethane foam. For example, wool-based insulation was found, in terms of GWP and HTP, to produce 2.1

\times

10⁴ kg CO₂-eq and 760.1 kg DCB-eq, respectively, and expanded polystyrene had similar results with respect to GWP, AP, and EP as 2.1

\times

10⁴ kg CO₂-eq, 23.3 kg SO₂-eq, and 2.7 kg Phosphate-eq, respectively. In fact, the research findings point out the shortcomings of current design practices in selecting insulation materials for marine vessels, while providing meaningful insights into the importance of the selection of appropriate insulation materials for marine vessels for cleaner shipping. Therefore, it is believed that this paper will make a sound contribution to enhancing future design practice and regulatory frameworks in response to environmental issues in the marine industry. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection)

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