Search Results (13)

To address greenhouse gas (GHG) emissions from the maritime sector, the European Union (EU) has introduced the FuelEU Maritime regulation to incentivize ships to adopt diversified compliance pathways and energy solutions. This study aims to determine the optimal alternative fuel configurations for dual-fuel ships of different types under environmental, economic, and regulatory constraints. An integrated environmental and cost assessment model from a well-to-wake (WtW) perspective to systematically evaluate the environmental benefits and economic feasibility of fossil-based, bio-based, and renewable electricity-based alternative fuels applied in dual-fuel ships. By incorporating the PROMETHEE II method within a multi-criteria decision analysis (MCDA) framework, together with the CRITIC objective weighting method, the study enables a robust ranking of alternative fuel configurations across three key dimensions: environmental performance, cost feasibility, and regulatory compliance. The results indicate that, regardless of ship type, the very low sulfur fuel oil (VLSFO) + marine gas oil (MGO) and VLSFO + methanol (MEOH) combinations fail to meet the GHG intensity targets for 2025–2050. Only the VLSFO + electrolytic liquid hydrogen (E-LH₂) and VLSFO + electrolytic ammonia (E-NH₃) configurations are compliant. Although e-fuels incur the highest annual costs, the EU compliance penalty associated with fossil fuels increases exponentially. In contrast, e-fuels retain long-term cost advantages, ultimately driving a sector-wide transition toward e-fuel-dominated energy structures by 2050. Their superior environmental performance and regulatory compatibility emerge as the core drivers of the maritime energy transition. Full article

The amendment to MARPOL Annex VI, which limits the sulfur content in marine fuels to a maximum of 0.5 wt.%, came into effect in January 2020. This includes reducing sulfur oxide (SO_X) emissions and establishing nitrogen oxide (NO_X) emission standards (Tiers I, II, and III) based on the ship’s engine type and construction date. Furthermore, the regulations require oil tankers to control volatile organic compound (VOC) emissions and prohibit the installation of new equipment containing ozone-depleting substances. After a four-year exploration phase, global shipping companies still lack consistent evaluation criteria for the selection and use of alternative fuels, resulting in divergence across the industry. According to the latest data, methanol can reduce NO_X, SO_X, and particulate matter (PM) emissions by approximately 80%, 99%, and 95%, respectively, compared to traditional heavy fuel oil. Furthermore, green methanol has the potential for near-zero greenhouse gas emissions and can meet the stringent standards of Emission Control Areas. Therefore, this study adopts a cost-benefit analysis method to evaluate the feasibility and implementation benefits of two promising strategies: methanol dual fuel and very low-sulfur fuel oil (VLSFO). A 6600-TEU container ship was selected as a representative case, and the evaluation was conducted by replacing an older ship with a newly built one. The reductions in total pollutants and CO₂-equivalent emissions of the container ship, as well as the cost-effectiveness of each specific strategy, were calculated. This study found that, in the first five years of operation, the total incremental cost of Vessel A, which uses 100% VLSFO, will be significantly lower than that of Vessel B, which uses a blend of 30% e-methanol + 70% VLSFO as fuel. Furthermore, compared to a scenario without any improvement strategies, the total incremental cost for Vessels A and B will increase by 69.90% and 178.15%, respectively, over five years. Vessel B effectively reduced the total greenhouse gas emission equivalent (CO₂e) of CO₂, CH_4, and N₂O by 24.72% over five years, while Vessel A reduced the CO₂e amount by 12.18%. Furthermore, the cost-benefit ratio (CBR) based on total pollutant emission reduction is higher for Vessel A than for Vessel B within five years of operation. However, in terms of the cost-effectiveness of CO₂e emission reduction, the CBR of Vessel A becomes lower than Vessel B after 4.7 years of operation. Therefore, Vessel A’s strategy should be considered a short-term option for reducing CO₂e within 4.7 years, whereas the strategy of Vessel B is more suitable as a long-term solution for more than 4.7 years. Full article

The conventional utilization of fossil fuels precipitates uncontrolled carbon dioxide and sulfur oxides emissions, thereby engendering pronounced atmospheric pollution and global health ramifications. Within the maritime domain, concerted global initiatives aspire to mitigate emissions by 2050, centering on the adaptation of engines, alteration of fuel compositions, and amelioration of exhaust gas treatment protocols. This investigation pioneers experimentation with marine gas oil augmented by methanol, a practice conventionally encumbered by prohibitively expensive additives. Successful amalgamation of methanol, animal-derived biodiesel, and marine gas oil (MGO) is empirically demonstrated under meticulously controlled thermal conditions, creating a homogeneous blend with virtually zero sulfur content and reduced carbon content, featuring characteristics akin to conventional marine gas oil but with no use of expensive emulsifiers. This new blend is suitable for employment in maritime engines utilizing Delaval technology, yet with significantly lower energy requirements compared to those necessitated using conventional very low sulfur fuel oil (VLSFO) with a maximum sulfur content of 0.5% w/w. Full article

With the implementation of the International Maritime Organization’s (IMO) sulfur cap 2020, shipowners have had to choose suitable sulfur oxide emission abatement solutions to respond to this policy. The use of Very Low Sulfur Fuel Oil (VLSFO) and the installation of scrubbers are the main response solutions for bulk carriers today. In recent years, the epidemic has gradually improved, and the options facing shipowners may change. Based on the Clarkson Shipping Intelligence Network, this paper collects data related to newbuilding bulk carriers after the implementation of this policy, considers several factors affecting shipowners’ decision, and adopts a machine learning approach for the first time to build a model and make predictions on emission abatement solutions to provide some reference for shipowners to choose a more suitable solution. The results of the study show that the Extreme Gradient Boosting (XGBoost) model is more suitable for the problem studied in this paper, and the highest prediction accuracy of about 84.25% with an Area Under the Curve (AUC) value of 0.9019 is achieved using this model with hyperparameter adjustment based on a stratified sampling divided data set. The model makes good predictions for newbuilding bulk carriers. In addition, the deadweight tonnage and annual distance traveled of a ship have a greater degree of influence on the choice of its option, which can be given priority in the decision making. In contrast to traditional cost–benefit analyses, this study incorporates economic and non-economic factors and uses machine learning methods for effective classification, which have the advantage of being fast, comparable, and highly accurate. Full article

This study performed a technical–economic analysis for ship-based ammonia transportation to investigate the feasibility of international ammonia transportation. Ammonia is considered to be a vital hydrogen carrier, so the international trade in ammonia by ship will considerably increase in the future. This study proposed three scenarios for transporting ammonia from the USA, Saudi Arabia, and Australia to South Korea and employed an 84,000 m³ class ammonia carrier. Not only traditional very low sulfur fuel oil (VLSFO)/marine diesel oil (MDO) but also LNG and ammonia fuels were considered as propulsion and power generation fuels in the carrier. A life-cycle cost (LCC) model consisting of capital expenditure (CAPEX) and operational expenditure (OPEX) was employed for the cost estimation. The results showed that the transportation costs depend on the distance. The unit transportation cost from the USA to South Korea was approximately three times higher than that of Australia to South Korea. Ammonia fuel yielded the highest costs among the fuels investigated (VLSFO/MGO, LNG, and ammonia). When using ammonia fuel, the unit transportation cost was approximately twice that when using VLSFO/MDO. The fuel costs occupied the largest portion of the LCC. The unit transportation costs from Australia to South Korea were 23.6 USD/ton-NH3 for the LVSFO/MDO fuel case, 31.6 USD/ton-NH3 for the LNG fuel case, and 42.9 USD/ton-NH3 for the ammonia fuel case. This study also conducted a sensitivity analysis to investigate the influence of assumptions, including assumed parameters. Full article

Since the implementation of the sulfur cap legislation in 2020, marine very-low-sulfur fuel oil, often known as VLSFO, has become a crucial source of fuel for the contemporary shipping industry. However, both the production and utilization processes of VLSFO are plagued by the poor miscibility of the cutter fraction and the residual fraction, which can result in the precipitation of asphaltene. In this study, biodiesel was chosen as a cutter fraction to improve the stability and compatibility of asphaltene in VLSFO because of its environmental benefit and strong solubility. The average chemical structure of asphaltene derived from the marine low-sulfur fuel oil sample was analyzed using element analysis, FTIR, ¹HNMR, and time-flight spectroscopy. The composition of biodiesel was analyzed using GC-MS. It was found that the asphaltene had a feature of a short side chain, low H/C ratio, high aromaticity, and a high proportion of heteroatoms. Both laboratory experiments and molecular dynamic simulations were applied to investigate the dispersion effect and mechanism compared with other dispersants. The dispersion effect of biodiesel was studied using measurements of the initial precipitation point (IPP), dispersion improvement rate, and morphology of asphaltene in the model oil. Experimental results revealed that biodiesel was fully compatible with heavy fuel oil and that it can postpone the IPP from 46% to 54% and increase the dispersion improvement rate to 35%. Molecular dynamics (MDs) simulation results show that biodiesel can form strong interactions with the fused aromatics structures and heteroatoms in the asphaltene; such interactions can increase the solubility of asphaltene and acts as a “connection bridge” to promote the dispersion effect of asphaltene molecules. Full article

Analysis of the very-low-sulfur fuel oil (VLSFO) and ultra-low-sulfur fuel oil (ULSFO) bunkered in key ports in Asia, the Middle East, North America, Western Europe, and Russia is presented. The characteristics of said fuels, including density, sulfur content, kinematic viscosity, aluminum and silicon content, vanadium and nickel content, as well as pour point are investigated. Furthermore, the main trends and correlations are also discussed. Based on the graphical and mathematical analysis of the properties, the composition of the fuels is predicted. The key fuel components in Asian ports, the most important of which is Singapore, are hydrodesulfurized atmospheric residues (AR) (50–70%) and catalytic cracker heavy cycle oil (HCO) (15–35%) with the addition of other components, which is explained by the presence of a number of large oil refining centers in the area. In the Middle East ports, the most used VLSFO compositions are based on available resources of low-sulfur components, namely hydrodesulfurized AR, the production facilities of which were recently built in the region. In European ports, due to the relatively low sulfur content in processed oils, straight-run AR is widely used as a component of low-sulfur marine fuels. In addition, fuels in Western European ports contain on average significantly more hydrotreated vacuum gas oil (21%) than in the rest of the world (4–5%). Finally, a mixture of hydrotreated (80–90%) and straight-run fuel oil (10–15%) with a sulfur content of no more than 2.0–2.5% is used as the base low-sulfur component of marine fuels in the ports of Singapore and the Middle East. Full article

The paper presents a comparison of the fuel oil (FO) consumption and carbon dioxide (CO₂) emissions of a container ship’s 8000 twenty-foot equivalent unit (TEU) during oceanographic navigation. The evaluation has two types of FOs: a 3.4% heavy fuel oil with desulfurization (HFOWD) and a 0.5% very-low-sulfur fuel oil (VLSFO), based on the sulfur cap policy of the International Maritime Organization (IMO). The results show the average FO consumption at 130 tons/day of HFOWD and 141 tons/day of VLSFO, which means shifting to VLSFO increases fuel consumption 8.4% more than the HFOWD. The average CO₂ emissions are 429 tons/day of the HFOWD and 471 tons/day of the VLSFO, indicating an 9.5% increase in CO₂ emissions when the IMO adopts the low-sulfur fuel policy. Moreover, the VLSFO blending of various chemicals further deteriorates and wears out the main engine of the ship. IMO’s low-sulfur fuel policy significantly reduced the emission of sulfur oxides (SO_X) and particulate matter emissions. Still, we should not ignore the fact that adopting VLSFO may cause more CO₂ emissions. Therefore, while switching to low-sulfur fuels, the maritime industry should improve the related energy efficiency to reduce fuel consumption and CO₂ emissions. Full article

The demand for very low sulfur fuel oil (VLSFO) with a sulfur content of less than 0.5% has increased since the IMO2020 regulations were published. However, most VLSFOs for marine fuel are produced by blending two fuel oils with different sulfur contents, which causes some problems, such as sludge formation. This study investigates the effect of ultrasonic irradiation frequency (25 and 72 kHz), ultrasonic irradiation time (0, 12, and 24 h), and the blending ratio (marine gas oil (MGO) and bunker-A (B-A) with weight ratios of 25:75, 50:50, and 75:25 on the characteristics of blended VLSFO. After 12 h of irradiation time and a frequency of 25 kHz, the amount of carbon residue decreases with increasing MGO content; it decreases by 33% for 75% MGO. However, at 72 kHz, the carbon residue increases with increasing MGO content, implying that the change in carbon residue depends on the ultrasonic frequency. After 24 h, the carbon residue does not decrease in any scenario; however, it does increase in some cases due to asphaltene reaggregation caused by excessive ultrasonic irritation. The sulfur content decreases by approximately 4% for the 100% B-A condition. Full article

Quality issues concerning very low-sulfur fuel oil (VLSFO) have increased significantly since the IMO sulfur-limit regulation became mandatory in 2020, as most VLSFO is produced by blending high-sulfur fuel oil (HSFO) with VLSFO. For instance, the conversion of VLSFO paraffins (C₁₉ or higher alkanes) into waxes at low temperatures adversely affects cold flow properties. This study investigates the effects of ultrasonication on the chemical composition, dispersion stability, and sulfur content of samples prepared by blending ISO-F-DMA-grade marine gas oil (i.e., VLSFO) and ISO-F-RMG-grade marine heavy oil (i.e., HSFO) in volumetric ratios of 25:75 (BFO1), 50:50 (BFO2), and 75:25 (BFO3). The paraffin content decreased by 19.2% after 120 min of ultrasonic irradiation for BFO1 by 16.8% after 30 min for BFO3. The decrease in the content of high-molecular-weight compounds was faster at higher HSFO content; however, ultrasonication for longer-than-optimal times induced reaggregation, and thus, increased the content of high-molecular-weight compounds and decreased dispersion stability. In addition, ultrasonication did not significantly affect the sulfur content of BFO1 but decreased those of BFO2 (by 19% after 60 min) and BFO3 (by 25% after 30 min). Desulfurization efficiency increased with the increasing content of HSFO, as water present therein acted as an oxidant for oxidative desulfurization. Full article

There are excellent offshore wind resources in the ocean off the west coast of Taiwan, and renewable offshore wind power has been actively developed in recent years. This study intends to establish a cost-effectiveness assessment model to compare the pollutant emissions and cost benefits of traditional fossil fuel and fuel cells used as the propulsion force of working vessels in Taiwan’s offshore wind farms. According to MARPOL, vessels should use very-low-sulfur fuel oil (VLSFO) with sulfur content of less than 0.5 wt. %. Therefore, this study proposes two strategies: changing marine power from VLSFO to ultra-low-sulfur diesel (ULSD) and a proton exchange membrane fuel cell (PEMFC). The emission reduction and cost benefit were analyzed in comparison with the original condition when VLSFO was used. The results show that compared with the total cost of VLSFO, the total costs of Strategy ULSD and Strategy PEMFC increase by 7.5% and 51.2%, respectively, over five years. Strategy PEMFC brings environmentally friendly benefits primarily by reducing SO_x, NO_x, HC, PM, and CO₂ emissions by 100%, 97.4%, 91.8%, 81%, and 81.6%, respectively, as compared with VLSFO. The cost–benefit ratio (CBR) of Strategy ULSD was higher than that of Strategy PEMFC in the first three years after improvements were made, and then the trend reversed. Strategy PEMFC is suitable as an alternative marine power source for the medium- and long-term (more than three years), while Strategy ULSD is suitable as a short-term investment for less than three years. Full article

Ships are an important part in international trade transportation and a major source of pollution. Therefore, the International Maritime Organization (IMO) implemented an amendment to the International Convention for the Prevention of Pollution from Ships (MARPOL) Annex VI, which stipulates that the sulfur content in marine fuel oil shall not exceed 0.5 wt.% starting in 2020. In order to meet the IMO low sulfur policy, shipping lines could adopt one of the following strategies: (1) using very low sulfur fuel oil (VLSFO), i.e., with sulfur content less than 0.5 wt.%; (2) installing scrubbers or other exhaust gas aftertreatment systems; or (3) replacing current fuels with clean alternative fuels such as natural gas. This study evaluates the feasibility and benefits of these strategies for shipping lines in order to determine the most cost-effective measures. First, according to the feasibility of the strategies evaluated by SWOT analysis, although scrubbers can reduce emissions of sulfur oxides into the atmosphere, more and more countries are restricting the discharge of wastewater from open-loop scrubbers into their waters. Instead, VLSFO and liquefied natural gas (LNG) are good choices in terms of environmental protection and economic benefits. Therefore, this study further evaluates the two strategies of replacing high sulfur fuel oil (HSFO) with VLSFO and converting diesel engines to LNG engines based on a cost-benefit methodology. This study took an 8500 TEU container vessel, which is powered by a marine diesel engine with the nominal power of 61,800 kW, sailing the Asian-European route as an example, and calculated the total incremental costs, pollutant emission reductions, and cost benefits arising from the implementation of the VLSFO and LNG strategies, respectively. According to the results of this study, the total incremental cost of LNG is higher than that of VLSFO in the first 4.7 years, but this gradually decreases, making the gap of the total incremental costs between the two strategies wider year by year. In comparison with using HSFO without any improvement, the total incremental costs of the VLSFO and LNG strategies increase by 12.94% and 22.16% over the following five years, respectively. The use of LNG can significantly reduce SOx, PM, NOx, and CO₂ emissions; on the other hand, it leads to more CH₄ emissions than the VLSFO strategy. Compared to doing nothing, the cumulative reduction rates of SOx, PM, NOx, and CO₂ emissions over the next five years after the adoption of the LNG strategy are 3.6%, 7.0%, 70.4%, and 15.7%, respectively. The higher emission reduction rates of LNG compared to VLSFO illustrate that the former has a good effect on the suppression of exhaust gas pollution. In terms of the cost-benefit evaluation of the two strategies, this study shows that the VLSFO strategy is more cost-effective than the LNG strategy in the first 2.5 years, but that the cost-benefit ratio of the latter increases year by year and exceeds that of the former, and the gap between them widens year by year. Based on the evaluation results of this study, the LNG strategy is suitable for ocean-going container vessels with fixed routes and younger or larger sized vessels to meet the IMO low sulfur policy. In contrast, the VLSFO strategy is appropriate for old merchant ships with fewer container spaces. LNG is a suitable medium- and long-term strategy, i.e., for more than 2.5 years, for shipping lines to meet the IMO low sulfur policy, while VLSFO is a suitable short-term strategy. Full article

According to the amendment of the “International Convention for the Marine Prevention of Pollution from Ships” (MARPOL), Annex VI stating that the sulfur content in marine fuel oil cannot exceed 0.5 wt. % came into effect in 2020. This study uses cost-benefit analysis method to evaluate the feasibility and implementation benefits of those strategies. A container ship serving on the ship route is selected as a representative. It is found that the very low-sulfur fuel oil (VLSFO) strategy has a higher total incremental cost than the scrubber strategy in the first 4.14 years, but then, the trend is reversed. After this container ship is equipped with a scrubber, the pollutant emission reduction is 5% higher than the condition of VLSFO only in the first year. The SOx and PM emission reduction rates of VLSFO strategy are higher than that of the scrubber strategy by 9% and 25%, respectively, within five years. In addition, during 3.3 years after the scrubber is installed, the cost-benefit ratio is higher than that of the VLSFO strategy. Hence, the scrubber for the ocean route container ships is merely a short-term compliance strategy within 3.3 years. In contrast, the low sulfur fuel oil strategy that less pollutant is emitted is a compliance strategy for periods longer than 3.3 years. Full article