Environmental and economic performance investigation of natural gas and methanol as a marine alternative fuel.

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Mahmoud Abdel Nasser, Mohamed M. Elgohary, Maged Abdelnaby, Mohamed R. Shouman This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1947354/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Emissions from ships are a serious global issue due to their effects on environmental damage, particularly global warming of the atmosphere. As a result, the International Maritime Organization (IMO) places a high priority on environmental protection by reducing exhaust emissions by at least 50% by 2050. Among the IMO's proposed measures, using alternative marine fuels such as natural gas and methanol instead of conventional fuels has been prioritised. In this paper, a comparative study between convert diesel engine into dual fuel engine operated with alternative fuels such as methanol or natural gas is carried out. Environmental and economic assessment of the natural-dual fuel engine and methanol- dual fuel engine is conducted. A13-class container ship is investigated as a case study. The evaluation results show that using natural gas in a dual fuel engine with a percentage (95% NG and 5% MDO) reduces NOx, SOX, CO2, PM, and CO pollutions by 83%, 95%, 19.4%, 95%, and 32.6%, respectively, while the emissions percentage will be 81.2%, 95%, 57.1%, 95%, and 58.4%, in order, when using methanol as a dual fuel with percentage 95% Methanol. Moreover, the cost-effectiveness of using natural gas was 769.25 $ /ton, 3304.1 $ /ton, 81.2 $ /ton. 60082.64 $ /ton, and 23782.84 $ /ton for NOx, SOx, CO2, PM, and CO, in the order, while for methanol, was 850.67 $ /ton, 3340.1 $ /ton, 45.588 $ /ton, 55450.87 $ /ton, and 13274.11 $ /ton, respectively. Ship emission reduction Natural gas Dual fuel engine Methanol IMO regulations Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Introduction Global environmental change compels us to alter our energy production and consumption practices. According to the findings of the world's air analysts, emission reductions are required to maintain a critical separation from fundamental changes in the planet's atmosphere, which have disastrous consequences for human well-being and the overall climate. According to recent International Maritime Organization IMO statistics, ships emit a significant amount of carbon dioxide (CO2), nitrogen oxides (NOx), sulfur oxides (SOx), particulate matter (PM), and carbon monoxide (CO) (Elkafas et al., 2019 ). Furthermore, studies have demonstrated that ships produce annually approximately 1.1 Gt of carbon dioxide (CO2), accounting for 3% of global greenhouse gas (GHG) pollution, in addition to 2.3 Mt of sulfur dioxide (SOx), 3.2 Mt of nitrogen oxides (NOx), 1.4 Mt of particulate matter (PM), and 936 thousand tons of carbon monoxide (CO) (Ammar and Seddiek 2020a ; IMO 2014b ). IMO has established stringent targets to significantly reduce NOx, SOx, CO2, PM, and CO air-quality-related emissions. For NOx emission, regulation 14 is applied on marine diesel engines of over 130 kW output power, while to reduce SOx and PM pollutions, the sulfur content of the used fuel is limited (Yang et al., 2012 ). In terms of CO2 emission, the IMO introduced two ways to evaluate a ship's compliance with international regulations. These indicators are the Energy Efficiency Design Index (EDDI) and the Energy Efficiency Operation Index (EEOI) (Rehmatulla et al., 2017 ). Fig. 1, shows that there are approximately 54,743 merchant ships contributing to international shipping of goods and passengers. These ships account for 55% of total CO2 emissions (Olmer et al., 2017 ). Among of these ship types, container ships appear to be the type that contribute by the highest percent of CO2 emissions. Several methods that can be used to reduce GHG pollution from ships, according to mitigating measures, include propulsion systems, ship design, renewable energy, and alternative fuels (El Gohary et al., 2016; Sadek and Elgohary 2020 ). Searching for alternative marine fuels is considered the best solution method to solve the fossil fuel depletion problem. The primary alternative marine fuel types can be divided into two categories liquid fuels (methanol, biodiesel, and ethanol) and gaseous fuels (natural gas, hydrogen, and propane). Biodiesel is a type of green alternative fuel that emits less soot (PM), unburned hydrocarbons, carbon monoxide (CO), and sulfur dioxide (SO2). However, it performs poorly at low temperatures, and increased demand for its production has resulted in a food crisis, as well as an increase in NOx emissions (Kesieme et al., 2019 ). Studies have shown that ethanol can be used as an alternative fuel in marine applications, with combustion releasing only carbon dioxide and water, but with a poor start in cold weather. The main issue with hydrogen as an alternative fuel is its high cost of production and use, particularly when renewable energy is used to produce hydrogen fuel (Elgohary and Seddiek 2015). Methanol (ME) and liquid natural gas (LNG) are the best types of alternative fuels that can be used in marine engines. Natural gas (NG) is considered the most promising option for lowering GHG emissions. Methane (CH4) is the primary component of (NG); it contains the least amount of carbon and sulfur, which reduces CO2 and SOx emissions (Elgohary et al., 2015 ). Furthermore, when compared to diesel, natural gas combustion produces significantly less nitrogen oxide (NOx). Natural gas can be found in compressed form or in liquid form (Cheenkachorn et al., 2013 ). Liquid natural gas (LNG) is more efficient compared to compressed natural gas (CNG) in terms of safety, transportation, and storage (Li et al., 2015 ). LNG is preferred for long-term use, is more cost-effective in long-distance transportation systems, and is more environmentally friendly (Spoof et al., 2020; Arteconi et al., 2010 ). Methanol (ME) is another type of alternative marine fuel that can be used to reduce marine pollution and meet IMO 2020 requirements (Methanol 2018). Many research projects investigated methanol as a marine fuel such as Methaship, SPIRETH project, and Swedish EffShip, demonstrating methanol's ability to reduce NOx, SOx, CO2, PM, and CO emissions (Andresson et al., 2020; Dierickx et al., 2018). The aim of this research is to evaluate the environmental and technical benefits of using alternative fuels as a marine fuel. In addition to economic effects of using dual fuel engine with alternative fuel. This assessment is based on a comparative study between two alternative fuels, natural gas (NG) and methanol (ME) in terms of environmental and economic efficiency. A13-class container ship is investigated as a case study. Environmental Analysis Methodology Firstly, the total emission for ship during one travel per ton can be calculated by using Eq. The ship emission (EM) depends on the main engine power (P w ) in KW, the operation trip time (T) in h, the load factor (L f ) to take the consideration of maneuvering and standby during the trip, and fuel pollution factor (P f ) in g/kWh; (i) is the type of emission, (f) is the type of fuel (Ammar 2019; Ammar and Seddiek 2020 ). $${EM}_{trip,i,f}=\sum \left[T\left({P}_{w}.{L}_{f}.{P}_{f,i}\right)\right]$$ 1 The emission factor value is related to the type of exhaust. For CO2 emissions, the carbon content in a fuel, which varies from fuel to another, is the main parameter used to calculate the pollution factor for each fuel. Fig. 2 shows the carbon content for each fuel. CF is the conversation factor, and SFC is the specific fuel consumption (g/kwh) (Elkafas et al., 2021 ). $${P}_{co2}=SFC.CF$$ 2 In terms of NOx emissions, the IMO has issued a new regulation that calculates the pollution factor for NOx based on the ship's construction date, and the speed engine (n), which can apply to ships built after January 1, 2000 (Mostafa et al., 2021 ). $${P}_{NOX}=45.{n}^{-2}$$ 3 Because sulfur is the main component of SOX, the pollution factor for SOx is determined by the specific fuel consumption (SFC) and the percentage of sulfur in the fuel (S %). The following equation can be used to calculate P sox (ICF 2009). $${P}_{SOx}=SFC*\left(S\%\right)*2.1$$ 4 For particulate matter (PM), previous studies have shown that PM emissions are related to sulfur content (S) and are based on the specific fuel consumption, which can be calculated by using the following Eq (Cooper and Gustafsson 2004 ; Kasper et al., 2007 ). $${P}_{PM}=SFC*\left(0.15729*S\%-0.000377\right)+0.23$$ 5 In this study for a slow speed diesel engine (SSDE), the pollution factor such as P NOX , P sox , P CO2 , P PM , P co , and P HC for marine diesel oil, natural gas and methanol was shown in Table 1 , according to other studies (Ammar and seddiek 2017 ; Banawan et al., 2010 ; Seddiek and Elgohary 2014 ). Now, for a dual-fuel engine which is operated between two fuels, the total emission factor for each fuel is calculated with the effect of fuel percentage, as shown in the following Eq. Where, \({P}_{total}\) is the total emission factor for dual fuel engine, \({P}_{D}\) is the emission factor for pilot diesel fuel, and \({P}_{gas}\) is the emission factor for alternative fuel. $${P}_{total}=\left(Diesel\%\right)*{P}_{D}+\left(New-fuel\%\right)*{P}_{gas}$$ 6 Table 1 Emission factors for slow speed diesel engines Fuel type P NOX (g/kwh) P sox (g/kwh) P CO2 (g/kwh) P PM (g/kwh) P co (g/kwh) P HC (g/kwh) MDO 17 0.36 688.79 0.19 1.4 0.6 NG 2.16 0 548.2 0 0.92 1.4 ME 2.47 0 275 0 0.54 0.9205 NOx emission assessment: IMO provides a regulation to prevent pollution such as MARPOL Annex VI Regulation 13, which addresses the NOx Emission. This regulation is applied to engines with output power greater than 130 KW and for ships built on or after 1 Jan 2000. The reduction of NOx emission is passed through 3 levels: Tier I, Tier II and Tier III, which were implemented on 1 Jan 2000, 2011, and 2016, respectively, based on the engine speed (n), as shown in Fig 3. Tier III aims to reduce NOx by 80% compared with Tier I and is applied in the Emission Control Area (ECA). For SOx emissions, IMO adopted Regulation 14 in MARPOL ANNEX VI to eliminate the sulfur content in marine fuel, which is the main factor in creating SOx pollution. In 2020, IMO issued a new globally regulation to reduce the sulfur content in fuel from 3.5% to 0.5% m/m, while for ECAs, the highest restriction was applied to reduce SOx from 1% to 0.1% in 2015, as illustrates in Fig. 4 (Trozzi and Lauretis 2019 ; Ammar and Seddiek 2020b ). For CO2 emissions, IMO adopted two methods: Energy Efficiency Design Index (EEDI) and Energy Efficiency Operational Indicator (EEOI) to evaluate the energy efficiency during operation and assessment for CO2 pollution. The EEDI is utilized to calculate the energy efficiency for vessels with 400 metric gross tonnages and higher, such as LNG and carriers, container ships, and tankers. The complex formula is executed to calculate EEDI based on a ship's emission, speed, and capacity (ABS 2013 ; Ančić and Šestan 2015 ). EEDI is computed according to IMO by using the following equation (Ammar and Seddiek 2020a ; Ammar 2018 ): For IMO, two EEDI values are used to assess the energy efficiency of vessels: required EEDI and it is the EEDI's constrictive limit and calculated for all fully deadweight vessel types by using Eq (7). Attained EEDI is the actual value which can be evaluated by using Eq (8). \(AE {CO}_{2} emission\) is calculated in case of the MCR of the main engine is greater than 1000 KW (IMO 2013 ; IMO 2018 ). Table 2 shows the description of equation parameters $${EEDI}_{require}=\left(1-\frac{X}{100}\right)*\frac{174.22}{{DWT}^{0.201}}$$ 7 $${EEDI}_{attained}=\frac{\left(ME\left(s\right)+ AE\left(s\right)- innovative technology\right) {CO}_{2} emissions }{Transport work}$$ 8 $$ME {CO}_{2} emissions=\left\{\sum _{i=1}^{nME}{P}_{ME\left(i\right)}.{C}_{FME\left(i\right)}.{SFC}_{ME\left(i\right)}\right\}$$ 9 $$AE {CO}_{2} emission=\left\{0.025*\left(\sum _{i=1}^{nME}{MCR}_{ME}+\frac{\sum _{i=1}^{nPTI}{P}_{PTI\left(x\right)}}{0.75}\right)+250\right\}*{C}_{FAE}.{SFC}_{AE}$$ 10 $$Reduction {CO}_{2} from innovative technology= \left\{\sum _{i=1}^{neff}{f}_{eff\left(i\right)}.{P}_{eff\left(i\right)}.{C}_{FME}.{SFC}_{ME}\right\}$$ 11 $$Transport work={f}_{i}.{f}_{1}.{f}_{w}.{f}_{c}.{V}_{ref}.Capacity$$ 12 Both of specific fuel consumption (SFC) and conversion factor (CF) are related on fuel types, and for dual fuel engine, the term of SFC*CF can be evaluated by Eq: $${SFC}_{DF}*{CF}_{Df}={SFC}_{PF}*{CF}_{Pf}+{SFC}_{Gas}*{CF}_{Gas}$$ 13 Energy Efficiency Operational Indicator (EEOI) assessment: The Energy Efficiency Operational Indicator (EEOI) is another methodology used by IMO to calculate CO2 gas emissions to the environment per ton of transport work, described in Eq. (14): where i is the number of voyages, FC is the fuel consumption mass, CF is the conversion factor from fuel to CO2 emission, m is the cargo weight on board, and D is the is the distance of a voyage in nautical miles (Tran 2017 ; IMO 2009 ). $$EEOI=\frac{{\sum }_{i}FC.{C}_{f}}{{\sum }_{i}{m}_{cargo}.D}$$ 14 Table 2 describe for EEDI Parameters X The reduction percentage in EEDI based on IMO requirements, which increases from 10–20%, and 30% in 2015, 2020, and 2025, respectively. DWT Dead Weight Tonnage ME, AE Main Engine, Auxiliary engine \({P}_{ME\left(i\right)}\) , \({P}_{AE}\) Power output from main engine, Power output from auxiliary engine \({SFC}_{ME\left(i\right)}, {SFC}_{AE}\) Specific fuel consumption for engines \({C}_{FME\left(i\right)}, {C}_{FAE}\) The fuel conversation factor from engines to \({CO}_{2} emission\) \({MCR}_{ME}\) The maximum continuous rating for main engine(s) \({P}_{PTI\left(x\right)}\) The shaft motor mechanical power divided by the generators weighted efficiency \(.{P}_{eff\left(i\right)}\) Power saving Because of innovative electrical energy efficient technology \({V}_{ref}\) The reference speed of the ship Capacity For passenger ships, it is the gross tonnage, and for container ships, it is 70% of the DWT. The total DWT is used as capacity for other types. \({f}_{i},{f}_{1},{f}_{w},{and f}_{c}\) The correction factor for specific ship types. \({f}_{w}\) is a non-dimensional factor that considers weather and environmental conditions and is calculated using Eq: . \({f}_{w}=0.0208*\text{ln}\left(Capacity\right)+0.633\) 2. Economic analysis methodology The economic analysis for using methanol or natural gas as a dual fuel evaluated by calculate the reduction of ship emissions annual cost-effectiveness E CE . This includes the annual capital cost reduction (ACC) of using alternative fuels onboard and the conversion process in $/ton, the maintenance and operation costs (AMC), and the amount of emission reduction (RE) in tons/year, as shown in Eq (Ammar and Seddiek 2020b ): $${EAC}_{CE}=\frac{ACC+AMC}{RE}$$ 15 Case Study: Container Ship In this study, A13-class container ship was selected to study the environmental and economic impacts assessment process from using alternative fuels instead of diesel fuel (Ammar and Seddiek 2020a ). The container vessel AL RIFFA, which is owned by a United Arab shipping company and operated by Hapag-Lloyd, Hamburg, was built in 2017 with 13500 containers and sailing under Malta flag. Table 3 depicts the ship's critical data (Al Riffa 2022). The ship operated with a slow speed diesel engine that uses marine diesel (0.1S%) to move cargo between several ports in the United States of America, the Mediterranean and the Middle East region with a maximum continuous rating of 74255.5 kW. The relation between the specific fuel consumption and MCR can be used to calculate SFC (El Gohary and Abdou 2011). For 85%MCR, SFC is 169.1 (g/kwh). As shown in Table 3 , for low-speed diesel engines, the emission factors are 17 g/kWh, 0.36 g/kWh, 688.79 g/kWh, 0.19 g/kWh, 1.4 g/kWh, and 0.6 g/kWh for NOx, SOx, CO2, PM, CO, and HC, respectively. Both NOx and SOx emissions are incompatible with current IMO limitation as IMO 2016 regulation reduced NOx emissions to less than 3.4 g/kWh and IMO 2020 regulation limited SOx to 0.5%. For this, the conversion process from using marine diesel fuel to dual fuel operated by alternative fuels (Methanol and natural gas) were evaluated to study its effect on marine pollution. Table 3 The container ship case study's primary dimensions Specifications A 13 Ship’s Name Al Riffa Year built 2012 IMO No. 9525912 Flag Malta Length over all (m) 366 L.P.P, (m) 350 Breadth over all (m) 48 Speed (kn) 23 Power (kw) 71770 TEU 13470 Deadweight (tdw) 145528 Gross Tonnage (GRT) 141077 Displacement (ton) 187974.2 Main engine MAN B&W 12K98ME Waste Heat Recovery (KW) 1818 T/G Shaft Generator [PTI/PTO] (KVA/KW) 3222/2578 Length of trip 20600 N.M The ship is currently powered by MAN B&W 12K98ME engine with an output of 48,280 KW at 104 rpm, and operated with marine diesel oil MDO (0.1% S). The length and high of the engine are 29 m and 14.6 m; the bore is 980 mm, and the stroke is 2660 mm. For each trip, load factors for are 85% during cruise, 20% in maneuvering, and 5% at standby modes. The main engine provides with three auxiliary engines (AE), rated 4,250 kW for each engine. Additional shaft generator connects with engine shaft to produce 2,578 KW for the electricity power. The study aims to convert the main engine into a dual fuel engine by preparing the cylinder head with two conventional valves for the pilot fuel and alternative fuels. Table 4 illustrates the main properties of methanol and natural gas. Table 4 Comparison between methanol, diesel, and natural gas properties Properties Diesel Natural gas Methanol Boiling Point 320 -161.5 o C 83.189 o C Freezing point 80 -182.6 o C -97.8 Octane Number -25 120 ∼ 130 109 ∼ 114 Flame speed (m/s) 0.867 0.38 0.445 Relative Density 0.8 ∼ 0.84 0.72 ∼ 0.8 0.787 ∼ 0.792 Carbon content 86.64 73 37.5 Hydrogen content 13.01 24 12.5 Oxygen content 0 0.4 50 Latent Heat 250 kj/kg 510 kj/kg 1062.2 kj.mol − 1 Specific Gravity 0.85 0.43 ∼ 0.47 0.896 ∼ 0.91 Flammability limits 0.6 ∼ 5.5 4 ∼ 15 6 ∼ 36 Ignition Temperature 355 o C 538 o C 470 ∼ 500 o C Results And Discussion The current study is primarily concerned with compare between the effects of using natural gas and methanol as an alternative fuel in a dual-fuel engine on the container ship. Firstly, the emission rates (SOx, NOx, and CO2) per trip were evaluated to assess the environmental performance of using methanol and natural gas. The emissions rates are compared based on IMO limitation. Secondly, energy efficiency design index EEDI and energy efficiency operational indicator EEOI are calculated to evaluate the CO2 emission and compare with IMO requirements at different phases. Finally, the impact of using natural gas and methanol on cost-effectiveness is measured. 4.1 Emission assessment To begin, the reduction effect of using natural gas and methanol as a dual fuel on emissions factors such as SOx, NOx, CO2, PM, CO, and HC was measured. Figure 5 illustrates the emission rates of using 95% dual fuel at (g/kwh). CO2 emission is reduced from 688.7 g/kwh to 555.23 g/kwh when using (95% NG and 5% MDO), and to 295.69 g/kwh when using (95% ME and 5% MDO). The methanol dual fuel decreased NOx emissions from 17 to 3.19 g/kwh, however, there was a slight increase compared to 2.902 for natural gas dual fuel. Both SOx and PM achieved maximum reduction for using dual fuel with ratios of 95% and 97.36%, respectively. HC emissions increased by using dual fuel from 0.6 g/kwh to 1.36 g/kwh and 0.9044 g/kwh for natural gas and methanol, in the order. NOx emissions are assessed by comparing them with the IMO limitation. According to IMO 2016 limitations, the NOx emission rate is based on engine speed and equals 3.5549 g/kwh. Figure 6 describes the reduction effect of using methanol and natural gas as a dual fuel compared with diesel fuel on NOx emissions. Using diesel fuel is not matching with IMO 2016 regulation, and with increase the ratio of methanol dual fuel and natural gas dual fuel, the NOx emission reduced to 2.6153 g/kwh and 2.3084 g/kwh, respectively. According to Fig.6, using natural gas dual fuel with ratio above 91% NG or Methanol with ratio above 93% ME will be compliant with the new IMO requirements. For Sox emissions, IMO 2020 imposed new requirements for fuel oil used on board ships should not exceed 0.5% sulfur that equals 0.0857 ton/hr. There was a similarity for using dual fuel by natural gas or methanol, which reduced the SOx rate to 0.0001738 ton/hr with (99% NG and 99% ME), as shown in Fig.7. It is now necessary to calculate the total emission per trip and the annual emission for each emission factor. For this, a dual fuel engine with 98% natural gas and 98% methanol was used to evaluate the emission factor, as shown in Table 5 . The load factor during maneuvering and standby mode was taken into consideration. It can be noticed the difference between emission factors during operation, maneuvering, and standby modes. Methanol dual fuel engine emits less SOx, CO2, and PM emissions better than natural gas; however, there is a slight increase in NOx emission. According to United Arab Shipping Company data, the Al Riffa container ship makes 6 trips per year at a rate of 49 days per trip. This equates to 295 days per year. By using Eq. (1), the total emission per trip and annual emission were calculated to assess the environmental effect from using a dual fuel engine. Table 6 illustrates the total reduction in emissions achieved by using a dual fuel engine. Using 98% natural gas dual fuel reduced the annual NOx, CO2, SOx, PM, and CO pollution by 85.55%, 20%, 98%, 98%, and 33.60%, respectively, while, using 98% methanol dual fuel recorded a reduction ratio by 83.76%, 58.87%, 98%, 98%, and 60.20%in the order. However, HC pollution increased for each dual fuel. type of emission emission factor (g/kwh) emission rate during operation (kg/hr.) emission rate during maneuvering (kg/hr.) emission rate during standby (kg/hr.) Table 5 the emission factor during, operation, maneuvering, and standby by using natural gas or methanol dual fuel 98% Natural gas (NG) dual fuel NOx 2.4568 132.8313 31.25443 7.813607 Sox 0.0072 0.389281 0.091596 0.022899 CO2 551.0118 29791.44 7009.752 1752.438 PM 0.0038 0.205454 0.048342 0.012086 CO 0.9296 50.2605 11.826 2.9565 HC 1.384 74.82845 17.60669 4.401674 98% Methanol (ME) dual fuel NOx 2.7606 149.2568 35.11925 8.779812 Sox 0.0072 0.389281 0.091596 0.022899 CO2 283.2758 15315.82 3603.721 900.9304 PM 0.0038 0.20545384 0.04834208 0.01208552 CO 0.5572 30.12602 7.088476 1.772119 HC 0.91409 49.42192 11.62869 2.907172 emission Fuel type Emission ton /trip Emission ton /year Reduction ton/year % Of reduction / year Table 6 Environmental analysis of the Al Riffa container ship. NOx Diesel fuel 1408.680 8429.770 NG dual fuel 203.145 1218.251 7211.519 85.55% ME dual fuel 228.266 1368.896 7060.874 83.76% Sox Diesel fuel 29.767 178.510 NG dual fuel 0.595 3.570 174.940 98.00% ME dual fuel 0.595 3.570 174.940 98.00% CO2 Diesel fuel 56954.000 341549.500 NG dual fuel 45561.529 273229.607 68319.893 20.00% ME dual fuel 23423.234 140467.655 201081.845 58.87% PM Diesel fuel 15.710 94.215 NG dual fuel 0.314 1.884 92.331 98.00% ME dual fuel 0.314 1.884 92.331 98.00% CO Diesel fuel 115.762 694.216 NG dual fuel 76.866 460.960 233.256 33.60% ME dual fuel 46.073 276.298 417.918 60.20% HC Diesel fuel 49.612 297.521 NG dual fuel 114.439 686.283 -388.762 -130.67% ME dual fuel 75.583 453.269 -155.748 -52.35% 4.2 Energy efficiency assessment Based on IMO requirements, evaluated, the EEDI is the most effective way to assess the energy efficiency of a ship. As mentioned, there are two values of EEDI, required values that can be calculated by Eq. (7), where X is the reduction percentage and increased from 10% in 2015 to 30% in 2025, as shown in Fig. 8. The required EEDI for the Al-Riffa ship, which was built in 2012, is 15.971 gCO2/ton-nm at the DWT 145528 ton. According to IMO, this value should be reduced to 20% at phase 2 and equal 12.777 gCO2/ton-nm. Another value is the attained EEDI, which is calculated using Eq. 8, and then compare this value with required EEDI in phase 2. Based on IMO regulations, the service speed (23 kn) can be used as a reference velocity (V ref ), and 70% DWT is considered as a ship capacity. The actual EEDI is 14.83 gCO2/ton-NM; this value reduced from required EEDI with ratio 7.14%, which is lower than the required EEDI, but will be incompatible with phase 2 from 2020 to 2025, as shown in Fig. 9. The reduction effects from using natural gas and methanol as a dual fuel engine were evaluated for variable ratios (70%, 80%, 90%, and 95%) to find the best percentage of dual fuel that achieves the required EEDI. Fig. 10, illustrates the reduction values from using natural gas and methanol as a dual fuel. The actual EEDI reduced from 11.27 g.CO2/ton. NM at 70% NG dual fuel to 10.827 g.CO2/ton. NM at 95% NG dual fuel, while methanol dropped to 8.362 g.CO2/ton. NM at 95% ME dual fuel. Both of dual fuels complicated with IMO regulation. Energy Efficiency Operational Indicator (EEOI) is another method adopted by IMO to measure the energy efficiency of the ships and carbon emissions during operations. According to Eq. (14), the EEOI is calculated based on the distance traveled, the transported TEU cargo, and the amount of fuel consumed per trip. For A13 class container ship, theTEU cargoes transported are 13500, over distance 20600 nautical miles. Figure 11 shows that the EEOI during operation is reduced from 0.00017 to CO2/TEU-NM when use MDO to 0.000146 tonCO2/TEU-NM and 0.000077 tonCO2/TEU-NM when use 95% NG and 95% ME, respectively. The calculations for maneuvering and standby were carried out based on 20% and 5% fuel consumption, in order. 4.3 Economic assessment The economic impact of converting the diesel engine into a dual fuel engine was examined in this section, and the cost-effectiveness of reducing ship NOx, CO2, and CO emissions by using natural gas and methanol was assessed. In terms of capital cost, to calculate the annual fuel cost, it is important to evaluate the total fuel consumption in the case of using diesel fuel and dual fuel, as shown in Table 7 . Because marine diesel fuel and alternative dual fuels are so similar, using natural gas or methanol requires only minor changes to diesel fuel infrastructure. As a result, the cost of bunkering facilities for diesel fuel and dual fuel is assumed to be the same in this study. The calculations are based on diesel, natural gas, and methanol fuel costs of 1320.8 $ /m3, 684.2 $ /m3, and 528.34 $ /m3, in addition to 8.0 $ /m3 for the bunkering prices (Afdc 2022). Table 8 illustrates the annual fuel cost for diesel fuel and dual fuel (natural gas or methanol) Table 7 Al Riffa container ship main engine fuel consumptions. Fuel consumption (m3) diesel engine Dual fuel engine with 90% Natural gas Dual fuel engine with 90% Methanol MDO Natural gas MDO Methanol MDO per trip 17,280 20,753 1,900 30,226 1,900 per year 103,632 124,941 11,400 181,267 11,400 Table 8 Fuel consumption annual cost for diesel and dual-fuel engine cost item Prices in (millions US $ /year) diesel engine NG-dual fuel engine ME-dual fuel engine Diesel fuel 136.877 15.057 15.057 Diesel bunkering 0.829 0.0912 0.0912 Natural gas 0 85.485 0 Natural gas bunkering 0 1 0 Methanol 0 0 95.771 Methanol bunkering 0 0 1.45 total fuel cost 137.706 101.6332 112.3692 For conversion cost from the main engine to a dual fuel engine, it is expected to be 10.72 million dollars with 285 $ /kW conversation rate (Andersson and Salazar 2015 ; Stefenson 2014 ). For operation and maintenance costs, according to data collected, the total operation and maintenance cost is 714749 $ /years (Banawan et al., 2010 ). Now, the total cost-effectiveness calculated for each emission type based on the added annual cost of the conversion process as discussed by using Eq. (15). Fig. 12, shows the annual cost-effectiveness of the proposed dual-fuel engine in reducing ship emissions for the container ship. Conclusions The International Maritime Organization (IMO) highlighted various methods for lowering ship exhaust emissions and improving marine energy savings from both operational and technical perspectives. One of the effective long-term measures for reducing emissions and improving energy efficiency which presented in this paper is converting from using fossil fuel in a conventional diesel engine to a dual fuel engine operating with alternative fuels. Natural gas and methanol are becoming more appealing as alternatives to traditional marine fuels. This study provided a comparative analysis of using methanol or natural gas to achieve the best solution in a dual fuel engine in terms of environmental performance. Furthermore, the economics of using alternative fuels instead of marine diesel oil are discussed. The analysis' findings revealed the following: From an environmental standpoint, the analysis results show that using natural dual fuel engines with ration (95%NG and 5% MDO) reduces NOx, SOx, CO2, PM, CO emissions by 83%, 95%, 19.4%, 95%, and 32.6%, respectively. On the other hand, the emissions saved percentage by using 95% methanol as a dual fuel is 81.2%, 95%, 57.1%, 95%, and 58.4%, respectively. Moreover, converting a conventional diesel engine to a dual fuel engine powered by natural gas or methanol as an alternative fuel will comply with IMO 2016 and 2020 emission requirements for NOX and SOx with marine diesel oil percentages less than 10%. From energy efficiency point of view, according to energy efficiency design index EEDI techniques, the dual fuel engine powered by (95% NG and 5% MDO) or (95% ME and 5% MDO) will meet IMO requirements. The required EEDI value for the third phase was 11.81 gCO2/ton-NM, and the attained EEDI value when using natural gas and methanol in a dual fuel engine was 10.827 g.CO2/ton and 8.362 g.CO2/ton-NM, respectively. Furthermore, using 95% natural gas or 95% methanol satisfies not only current IMO EEDI requirements but also future ones. In terms of cost-effectiveness, the suggested dual-fuel (95% NG + 5% MDO) engine will reduce NOx, SOx, CO2, PM, and CO emissions while saving 769.25 $ /ton, 3304.1 $ /ton, 81.2 $ /ton. 60082.64 $ /ton, and 23782.84 $ /ton, respectively. in addition to 850.67 $ /ton, 3340.1 $ /ton, 45.588 $ /ton, 55450.87 $ /ton, and 13274.11 $ /ton, in the order, when using dual-fuel (95% ME + 5% MDO) engine. Declarations Funding: - The authors declare that no funds, grants, or other support were received during the preparation of this manuscript Competing Interests: - The authors have no relevant financial or non-financial interests to disclose. Author Contributions: - All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Mahmoud Abdel Nasser, Mohamed M. Elgohary, Mohamed Shouman and Majed Abdelnabi. The first draft of the manuscript was written by Mahmoud Abdel Nasser and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Ethical Approval Not applicable. Consent to Publish The authors declare that they are approved to Publish the paper with title " Environmental and economic performance investigation of natural gas and methanol as a marine alternative fuel." to "Environmental Science and Pollution Research" journal. Consent to Participate The authors declare that they are agreeing to participate the scientific data of the paper with "Environmental Science and Pollution Research" journal Availability of data and materials The authors declare that they are approve to available any data and materials that relate with the paper. References A.G. Elkafas, M.M. Elgohary, M.R. Shouman, Numerical analysis of economic and environmental benefits of marine fuel conversion from diesel oil to natural gas for container ships, Environ. Sci. Pollut. Res. 28 (2021) 15210–15222. https://doi.org/10.1007/s11356-020-11639-6. ABS (2013) Ship energy efficiency measures: status and guidance. American Bureau of Shipping, Houston, pp 20–35 Afdc.energy.gov. 2022. Alternative Fuels Data Center: Fuel Prices. [online] Available at: https://afdc.energy.gov/fuels/prices.html [Accessed 7 August 2022]. Al Riffa - Hapag-Lloyd. (n.d.). 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Environ. 229 (2015) 365–375. https://doi.org/10.1177/1475090214522778. Methanol Institute. 2018. ISO specification is another step forward for Methanol as marine fuel. Available: https://www.methanol.org/ (Accessed 10 September 2018). Morsy El Gohary M, Abdou KM (2011) Computer based selection and performance analysis of marine diesel engine. Alex Eng J 50:1–11. https://doi.org/10.1016/j.aej.2011.01.002 Mostafa A. El-Manzalawy, Mohamed M. ElGohary, Maged M. AbdElnaby (2021). Technical and environmental performance investigation of Marine Alternative fuels. https://www.researchgate.net/publication/354177709 N.R. Ammar, I.S. Seddiek, Enhancing energy efficiency for new generations of containerized shipping, Ocean Eng. 215 (2020) 107887. https://doi.org/10.1016/j.oceaneng.2020.107887. Olmer N, Comer B, Roy B et al (2017) Greenhouse gas emissions from global shipping. International Council on Clean Transportation, Washington DC Placek, M. (2021, November 23). Global merchant fleet - number of ships by type. Statista. Retrieved August 9, 2022, from https://www.statista.com/statistics/264024/number-of-merchant-ships-worldwide-by-type/ Rehmatulla N, Calleya J, Smith T (2017) The implementation of technical energy efficiency and CO2 emission reduction measures in shipping. Ocean Eng 139:184–197. https://doi.org/10.1016/j.oceaneng.2017.04.029 Seddiek IS, Elgohary MM (2014) Eco-friendly selection of ship emissions reduction strategies with emphasis on SOx and NOx emissions. Int J Naval Archit Ocean Eng 6(3):737–748 Spoof-Tuomi K,Niemi S (2020) Environmental and economic evaluation of fuel choices for short sea shipping. Clean Technol 2:34–52. https://doi.org/10.3390/cleantechnol2010004 Stefenson, P. 2014. The Use of Biofuel in the Marine Sector or Methanol, the Marine Fuel of the Future. European Biofuels Technology Platform, Brussels, 15 October 2014. Tran TA (2017) A research on the energy efficiency operational indicator EEOI calculation tool on M/V NSU JUSTICE of VINIC transportation company, Vietnam. J Ocean Eng Sci 2(1):55–60 Trozzi C, Lauretis R De (2019) Air pollutant emission inventory guidebook. Tech report, Eur Environ agency Yang ZL, Zhang D, Caglayan O, Jenkinson ID, Bonsall S, Wang J, Huang M, Yan XP (2012) Selection of techniques for reducing shipping NOx and SOx emissions. Transp Res Part D Transp Environ 17:478–486. https://doi.org/10.1016/j.trd.2012.05.010 Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-1947354","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":133823564,"identity":"e1cc2788-567e-4d84-8932-e560cef7c340","order_by":0,"name":"Mahmoud Abdel Nasser","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/0lEQVRIiWNgGAWjYFACHhDBDGFLGEjIgegDD4jWYlFhYwzWkkC0loozaYkNIAY+LbrtZ49u+Nhmncfff/jYh5tth9Pnhx1+CLTFTk63AbsWszN5aTdntqUXS9xIS545s+1w7sbbaQZALcnGZgdwaDmQY3abt+1wYsMNHmNmSZCW2QkgLQcSt+HScv4NRMv88+c/M/8FOsxwdvoH/FpuQG3ZcCCHmUHiTFqCvHQOAVtuvDG7OeNceuLGG2nGDBIVNoYbpHMKDiQY4PHL+RyzGx/KrBPnnT/8GBSV8vKz0zd/+FBhJ4dLCyYwAKs0IFY5CMg3kKJ6FIyCUTAKRgIAAJf1ax8NkSYEAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0002-2778-9721","institution":"Alexandria University Faculty of Engineering","correspondingAuthor":true,"prefix":"","firstName":"Mahmoud","middleName":"Abdel","lastName":"Nasser","suffix":""},{"id":133823565,"identity":"2c21c71e-3891-48fa-bd3b-9ca08edf709a","order_by":1,"name":"Mohamed M. Elgohary","email":"","orcid":"","institution":"Alexandria University Faculty of Engineering","correspondingAuthor":false,"prefix":"","firstName":"Mohamed","middleName":"M.","lastName":"Elgohary","suffix":""},{"id":133823566,"identity":"f5f0f282-9f7a-4fee-acf1-d487c044d388","order_by":2,"name":"Maged Abdelnaby","email":"","orcid":"","institution":"Alexandria University Faculty of Engineering","correspondingAuthor":false,"prefix":"","firstName":"Maged","middleName":"","lastName":"Abdelnaby","suffix":""},{"id":133823567,"identity":"e5018905-c21f-4db8-bb47-6fa91fbcef13","order_by":3,"name":"Mohamed R. Shouman","email":"","orcid":"","institution":"Arab Academy for Science Technology and Maritime Transport","correspondingAuthor":false,"prefix":"","firstName":"Mohamed","middleName":"R.","lastName":"Shouman","suffix":""}],"badges":[],"createdAt":"2022-08-10 04:31:42","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1947354/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1947354/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":26176371,"identity":"cee331db-0e0b-4778-9c5b-3340c162f9ee","added_by":"auto","created_at":"2022-09-07 13:58:44","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":21835,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eNumber of merchant ships and their carbon emissions, by category in 2021. (Placek 2021).\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-1947354/v1/cf483b2d40954b82932dde4c.png"},{"id":26176142,"identity":"d0d9e5d6-905c-41e0-8068-6d10ddb21199","added_by":"auto","created_at":"2022-09-07 13:53:44","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":13504,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eCarbon contents and conversion factors of different fuel types\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-1947354/v1/5eb1843987646fb2c785ef91.png"},{"id":26175885,"identity":"00dec144-b993-44bb-8912-53756fcc2de4","added_by":"auto","created_at":"2022-09-07 13:48:44","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":13705,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eNOx emission limits for IMO regulation\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-1947354/v1/154995efacff5010176b347e.png"},{"id":26176370,"identity":"4da58345-89c6-435a-b51c-681c86fc00c0","added_by":"auto","created_at":"2022-09-07 13:58:44","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":15524,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSox emission limits for IMO regulation\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-1947354/v1/2f592ccb2243530b34d7fc88.png"},{"id":26176138,"identity":"2c31c04a-101d-4b28-8f65-5130ce9f650e","added_by":"auto","created_at":"2022-09-07 13:53:44","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":24011,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEmission rates of the proposed dual-fuel engine in comparison to diesel engines\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-1947354/v1/3b1b3a3999da8c14658ee713.png"},{"id":26176143,"identity":"8fb3a093-ca83-414b-8aea-5131fb7920d3","added_by":"auto","created_at":"2022-09-07 13:53:44","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":12571,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eRates of NOx emission at various pilot fuel percentages\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-1947354/v1/344ffd965bd60c1090c66fac.png"},{"id":26175889,"identity":"8aea8a51-d70e-4665-ab9a-a02727d47462","added_by":"auto","created_at":"2022-09-07 13:48:44","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":9979,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSOx emission levels at various pilot fuel percentages\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-1947354/v1/e4bf8e94055248d4f825d34f.png"},{"id":26175887,"identity":"cfa4cb39-04e5-4f56-b3e2-8ed7342accff","added_by":"auto","created_at":"2022-09-07 13:48:44","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":20927,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe required EEDI according to IMO regulation\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-1947354/v1/53985f81773e5a6f1cd49d17.png"},{"id":26176140,"identity":"f4ce2c30-1356-478e-aabc-30328798e227","added_by":"auto","created_at":"2022-09-07 13:53:44","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":28469,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe required EEDI for the Al-Riffa ship\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-1947354/v1/006d13359e65372c144aa9bc.png"},{"id":26175895,"identity":"f833bd1d-c9a9-4285-aed3-3ce3c926f51d","added_by":"auto","created_at":"2022-09-07 13:48:44","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":18205,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eRelative attained EEDI compared to reference value at different phases\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-1947354/v1/2de438ec31ba861815f33be0.png"},{"id":26175891,"identity":"55d48b94-cc40-4ec5-9ff5-912588f34f60","added_by":"auto","created_at":"2022-09-07 13:48:44","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":16067,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eCalculated EEOI for the case studies at the operational ship speeds.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-1947354/v1/f1496b6dcd864e2cb0239fa3.png"},{"id":26175893,"identity":"7fb08a8e-b600-4bf7-a74f-aa60e46be1c0","added_by":"auto","created_at":"2022-09-07 13:48:44","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":16133,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe annual cost-effectiveness of the proposed dual-fuel engine\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-1947354/v1/1684a13c73863872bc712d45.png"},{"id":29602309,"identity":"add501a2-06c2-40fa-b189-86d4336619cf","added_by":"auto","created_at":"2022-11-28 16:19:56","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":837008,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1947354/v1/70a1fc89-31fd-463b-b944-c8764d8d1508.pdf"}],"financialInterests":"","formattedTitle":"Environmental and economic performance investigation of natural gas and methanol as a marine alternative fuel.","fulltext":[{"header":"Introduction","content":"\u003cp\u003eGlobal environmental change compels us to alter our energy production and consumption practices. According to the findings of the world\u0026apos;s air analysts, emission reductions are required to maintain a critical separation from fundamental changes in the planet\u0026apos;s atmosphere, which have disastrous consequences for human well-being and the overall climate. According to recent International Maritime Organization IMO statistics, ships emit a significant amount of carbon dioxide (CO2), nitrogen oxides (NOx), sulfur oxides (SOx), particulate matter (PM), and carbon monoxide (CO) (Elkafas et al., \u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e). Furthermore, studies have demonstrated that ships produce annually approximately 1.1 Gt of carbon dioxide (CO2), accounting for 3% of global greenhouse gas (GHG) pollution, in addition to 2.3 Mt of sulfur dioxide (SOx), 3.2 Mt of nitrogen oxides (NOx), 1.4 Mt of particulate matter (PM), and 936 thousand tons of carbon monoxide (CO) (Ammar and Seddiek \u003cspan class=\"CitationRef\"\u003e2020a\u003c/span\u003e; IMO \u003cspan class=\"CitationRef\"\u003e2014b\u003c/span\u003e). IMO has established stringent targets to significantly reduce NOx, SOx, CO2, PM, and CO air-quality-related emissions. For NOx emission, regulation 14 is applied on marine diesel engines of over 130 kW output power, while to reduce SOx and PM pollutions, the sulfur content of the used fuel is limited (Yang et al., \u003cspan class=\"CitationRef\"\u003e2012\u003c/span\u003e). In terms of CO2 emission, the IMO introduced two ways to evaluate a ship\u0026apos;s compliance with international regulations. These indicators are the Energy Efficiency Design Index (EDDI) and the Energy Efficiency Operation Index (EEOI) (Rehmatulla et al., \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e). Fig. 1, shows that there are approximately 54,743 merchant ships contributing to international shipping of goods and passengers. These ships account for 55% of total CO2 emissions (Olmer et al., \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e). Among of these ship types, container ships appear to be the type that contribute by the highest percent of CO2 emissions. Several methods that can be used to reduce GHG pollution from ships, according to mitigating measures, include propulsion systems, ship design, renewable energy, and alternative fuels (El Gohary et al., 2016; Sadek and Elgohary \u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e). Searching for alternative marine fuels is considered the best solution method to solve the fossil fuel depletion problem. The primary alternative marine fuel types can be divided into two categories liquid fuels (methanol, biodiesel, and ethanol) and gaseous fuels (natural gas, hydrogen, and propane). Biodiesel is a type of green alternative fuel that emits less soot (PM), unburned hydrocarbons, carbon monoxide (CO), and sulfur dioxide (SO2). However, it performs poorly at low temperatures, and increased demand for its production has resulted in a food crisis, as well as an increase in NOx emissions (Kesieme et al., \u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e). Studies have shown that ethanol can be used as an alternative fuel in marine applications, with combustion releasing only carbon dioxide and water, but with a poor start in cold weather. The main issue with hydrogen as an alternative fuel is its high cost of production and use, particularly when renewable energy is used to produce hydrogen fuel (Elgohary and Seddiek 2015). Methanol (ME) and liquid natural gas (LNG) are the best types of alternative fuels that can be used in marine engines. Natural gas (NG) is considered the most promising option for lowering GHG emissions. Methane (CH4) is the primary component of (NG); it contains the least amount of carbon and sulfur, which reduces CO2 and SOx emissions (Elgohary et al., \u003cspan class=\"CitationRef\"\u003e2015\u003c/span\u003e). Furthermore, when compared to diesel, natural gas combustion produces significantly less nitrogen oxide (NOx). Natural gas can be found in compressed form or in liquid form (Cheenkachorn et al., \u003cspan class=\"CitationRef\"\u003e2013\u003c/span\u003e). Liquid natural gas (LNG) is more efficient compared to compressed natural gas (CNG) in terms of safety, transportation, and storage (Li et al., \u003cspan class=\"CitationRef\"\u003e2015\u003c/span\u003e). LNG is preferred for long-term use, is more cost-effective in long-distance transportation systems, and is more environmentally friendly (Spoof et al., 2020; Arteconi et al., \u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e). Methanol (ME) is another type of alternative marine fuel that can be used to reduce marine pollution and meet IMO 2020 requirements (Methanol 2018). Many research projects investigated methanol as a marine fuel such as Methaship, SPIRETH project, and Swedish EffShip, demonstrating methanol\u0026apos;s ability to reduce NOx, SOx, CO2, PM, and CO emissions (Andresson et al., 2020; Dierickx et al., 2018). The aim of this research is to evaluate the environmental and technical benefits of using alternative fuels as a marine fuel. In addition to economic effects of using dual fuel engine with alternative fuel. This assessment is based on a comparative study between two alternative fuels, natural gas (NG) and methanol (ME) in terms of environmental and economic efficiency. A13-class container ship is investigated as a case study.\u003c/p\u003e"},{"header":"Environmental Analysis Methodology","content":"\u003cdiv class=\"Section2\"\u003e\n \u003cp\u003eFirstly, the total emission for ship during one travel per ton can be calculated by using Eq. The ship emission (EM) depends on the main engine power (P\u003csub\u003ew\u003c/sub\u003e) in KW, the operation trip time (T) in h, the load factor (L\u003csub\u003ef\u003c/sub\u003e) to take the consideration of maneuvering and standby during the trip, and fuel pollution factor (P\u003csub\u003ef\u003c/sub\u003e) in g/kWh; (i) is the type of emission, (f) is the type of fuel (Ammar 2019; Ammar and Seddiek \u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e\n \u003cdiv class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$${EM}_{trip,i,f}=\\sum \\left[T\\left({P}_{w}.{L}_{f}.{P}_{f,i}\\right)\\right]$$ 1\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eThe emission factor value is related to the type of exhaust. For CO2 emissions, the carbon content in a fuel, which varies from fuel to another, is the main parameter used to calculate the pollution factor for each fuel. Fig. 2 shows the carbon content for each fuel. CF is the conversation factor, and SFC is the specific fuel consumption (g/kwh) (Elkafas et al., \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e\n \u003cdiv class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$${P}_{co2}=SFC.CF$$ 2\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eIn terms of NOx emissions, the IMO has issued a new regulation that calculates the pollution factor for NOx based on the ship\u0026apos;s construction date, and the speed engine (n), which can apply to ships built after January 1, 2000 (Mostafa et al., \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e\n \u003cdiv class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$${P}_{NOX}=45.{n}^{-2}$$ 3\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eBecause sulfur is the main component of SOX, the pollution factor for SOx is determined by the specific fuel consumption (SFC) and the percentage of sulfur in the fuel (S %). The following equation can be used to calculate P\u003csub\u003esox\u003c/sub\u003e (ICF 2009).\u003c/p\u003e\n \u003cdiv class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$${P}_{SOx}=SFC*\\left(S\\%\\right)*2.1$$ 4\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eFor particulate matter (PM), previous studies have shown that PM emissions are related to sulfur content (S) and are based on the specific fuel consumption, which can be calculated by using the following Eq (Cooper and Gustafsson \u003cspan class=\"CitationRef\"\u003e2004\u003c/span\u003e; Kasper et al., \u003cspan class=\"CitationRef\"\u003e2007\u003c/span\u003e).\u003c/p\u003e\n \u003cdiv class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$${P}_{PM}=SFC*\\left(0.15729*S\\%-0.000377\\right)+0.23$$ 5\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eIn this study for a slow speed diesel engine (SSDE), the pollution factor such as P\u003csub\u003eNOX\u003c/sub\u003e, P\u003csub\u003esox\u003c/sub\u003e, P\u003csub\u003eCO2\u003c/sub\u003e, P\u003csub\u003ePM\u003c/sub\u003e, P\u003csub\u003eco\u003c/sub\u003e, and P\u003csub\u003eHC\u003c/sub\u003e for marine diesel oil, natural gas and methanol was shown in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e, according to other studies (Ammar and seddiek \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e; Banawan et al., \u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e; Seddiek and Elgohary \u003cspan class=\"CitationRef\"\u003e2014\u003c/span\u003e). Now, for a dual-fuel engine which is operated between two fuels, the total emission factor for each fuel is calculated with the effect of fuel percentage, as shown in the following Eq. Where, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({P}_{total}\\)\u003c/span\u003e\u003c/span\u003e is the total emission factor for dual fuel engine, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({P}_{D}\\)\u003c/span\u003e\u003c/span\u003e is the emission factor for pilot diesel fuel, and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({P}_{gas}\\)\u003c/span\u003e\u003c/span\u003e is the emission factor for alternative fuel.\u003c/p\u003e\n \u003cdiv class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$${P}_{total}=\\left(Diesel\\%\\right)*{P}_{D}+\\left(New-fuel\\%\\right)*{P}_{gas}$$ 6\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003ctable border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eEmission factors for slow speed diesel engines\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFuel type\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP\u003csub\u003eNOX\u003c/sub\u003e (g/kwh)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP\u003csub\u003esox\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(g/kwh)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP\u003csub\u003eCO2\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(g/kwh)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP\u003csub\u003ePM\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(g/kwh)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP\u003csub\u003eco\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(g/kwh)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP\u003csub\u003eHC\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(g/kwh)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMDO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e688.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNG\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e548.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eME\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e275\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9205\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003eNOx emission assessment: IMO provides a regulation to prevent pollution such as MARPOL Annex VI Regulation 13, which addresses the NOx Emission. This regulation is applied to engines with output power greater than 130 KW and for ships built on or after 1 Jan 2000. The reduction of NOx emission is passed through 3 levels: Tier I, Tier II and Tier III, which were implemented on 1 Jan 2000, 2011, and 2016, respectively, based on the engine speed (n), as shown in Fig 3. Tier III aims to reduce NOx by 80% compared with Tier I and is applied in the Emission Control Area (ECA). For SOx emissions, IMO adopted Regulation 14 in MARPOL ANNEX VI to eliminate the sulfur content in marine fuel, which is the main factor in creating SOx pollution. In 2020, IMO issued a new globally regulation to reduce the sulfur content in fuel from 3.5% to 0.5% m/m, while for ECAs, the highest restriction was applied to reduce SOx from 1% to 0.1% in 2015, as illustrates in Fig. 4 (Trozzi and Lauretis \u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e; Ammar and Seddiek \u003cspan class=\"CitationRef\"\u003e2020b\u003c/span\u003e). For CO2 emissions, IMO adopted two methods: Energy Efficiency Design Index (EEDI) and Energy Efficiency Operational Indicator (EEOI) to evaluate the energy efficiency during operation and assessment for CO2 pollution. The EEDI is utilized to calculate the energy efficiency for vessels with 400 metric gross tonnages and higher, such as LNG and carriers, container ships, and tankers. The complex formula is executed to calculate EEDI based on a ship\u0026apos;s emission, speed, and capacity (ABS \u003cspan class=\"CitationRef\"\u003e2013\u003c/span\u003e; Ančić and \u0026Scaron;estan \u003cspan class=\"CitationRef\"\u003e2015\u003c/span\u003e). EEDI is computed according to IMO by using the following equation (Ammar and Seddiek \u003cspan class=\"CitationRef\"\u003e2020a\u003c/span\u003e; Ammar \u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e): For IMO, two EEDI values are used to assess the energy efficiency of vessels: required EEDI and it is the EEDI\u0026apos;s constrictive limit and calculated for all fully deadweight vessel types by using Eq (7). Attained EEDI is the actual value which can be evaluated by using Eq (8). \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(AE {CO}_{2} emission\\)\u003c/span\u003e\u003c/span\u003e is calculated in case of the MCR of the main engine is greater than 1000 KW (IMO \u003cspan class=\"CitationRef\"\u003e2013\u003c/span\u003e; IMO \u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e). Table 2 shows the description of equation parameters\u003c/p\u003e\n \u003cp\u003e$${EEDI}_{require}=\\left(1-\\frac{X}{100}\\right)*\\frac{174.22}{{DWT}^{0.201}}$$ 7\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$${EEDI}_{attained}=\\frac{\\left(ME\\left(s\\right)+ AE\\left(s\\right)- innovative technology\\right) {CO}_{2} emissions }{Transport work}$$ 8\u003c/div\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cdiv class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$$ME {CO}_{2} emissions=\\left\\{\\sum _{i=1}^{nME}{P}_{ME\\left(i\\right)}.{C}_{FME\\left(i\\right)}.{SFC}_{ME\\left(i\\right)}\\right\\}$$ 9\u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$$AE {CO}_{2} emission=\\left\\{0.025*\\left(\\sum _{i=1}^{nME}{MCR}_{ME}+\\frac{\\sum _{i=1}^{nPTI}{P}_{PTI\\left(x\\right)}}{0.75}\\right)+250\\right\\}*{C}_{FAE}.{SFC}_{AE}$$ 10\u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$$Reduction {CO}_{2} from innovative technology= \\left\\{\\sum _{i=1}^{neff}{f}_{eff\\left(i\\right)}.{P}_{eff\\left(i\\right)}.{C}_{FME}.{SFC}_{ME}\\right\\}$$ 11\u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$$Transport work={f}_{i}.{f}_{1}.{f}_{w}.{f}_{c}.{V}_{ref}.Capacity$$ 12\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eBoth of specific fuel consumption (SFC) and conversion factor (CF) are related on fuel types, and for dual fuel engine, the term of SFC*CF can be evaluated by Eq:\u003c/p\u003e\n \u003cdiv class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$${SFC}_{DF}*{CF}_{Df}={SFC}_{PF}*{CF}_{Pf}+{SFC}_{Gas}*{CF}_{Gas}$$ 13\u003c/div\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\"\u003e\n \u003ch2\u003eEnergy Efficiency Operational Indicator (EEOI) assessment:\u003c/h2\u003e\n \u003cp\u003eThe Energy Efficiency Operational Indicator (EEOI) is another methodology used by IMO to calculate CO2 gas emissions to the environment per ton of transport work, described in Eq. (14): where i is the number of voyages, FC is the fuel consumption mass, CF is the conversion factor from fuel to CO2 emission, m is the cargo weight on board, and D is the is the distance of a voyage in nautical miles (Tran \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e; IMO \u003cspan class=\"CitationRef\"\u003e2009\u003c/span\u003e).\u003c/p\u003e\n \u003cdiv class=\"Equation\"\u003e\n \u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$$EEOI=\\frac{{\\sum }_{i}FC.{C}_{f}}{{\\sum }_{i}{m}_{cargo}.D}$$ 14\u003c/div\u003e\u003c/div\u003e\u003cp\u003e\u003cstrong\u003eTable 2 describe for EEDI Parameters\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\u003ctable border=\"1\"\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\"\u003e\u003cp\u003eX\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\"\u003e\u003cp\u003eThe reduction percentage in EEDI based on IMO requirements, which increases from 10\u0026ndash;20%, and 30% in 2015, 2020, and 2025, respectively.\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\u003cp\u003eDWT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\"\u003e\u003cp\u003eDead Weight Tonnage\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\u003cp\u003eME, AE\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\"\u003e\u003cp\u003eMain Engine, Auxiliary engine\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({P}_{ME\\left(i\\right)}\\)\u003c/span\u003e\u003c/span\u003e, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({P}_{AE}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\"\u003e\u003cp\u003ePower output from main engine, Power output from auxiliary engine\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({SFC}_{ME\\left(i\\right)}, {SFC}_{AE}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\"\u003e\u003cp\u003eSpecific fuel consumption for engines\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({C}_{FME\\left(i\\right)}, {C}_{FAE}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\"\u003e\u003cp\u003eThe fuel conversation factor from engines to\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({CO}_{2} emission\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({MCR}_{ME}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\"\u003e\u003cp\u003eThe maximum continuous rating for main engine(s)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({P}_{PTI\\left(x\\right)}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\"\u003e\u003cp\u003eThe shaft motor mechanical power divided by the generators weighted efficiency\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(.{P}_{eff\\left(i\\right)}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\"\u003e\u003cp\u003ePower saving Because of innovative electrical energy efficient technology\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({V}_{ref}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\"\u003e\u003cp\u003eThe reference speed of the ship\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\u003cp\u003eCapacity\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\"\u003e\u003cp\u003eFor passenger ships, it is the gross tonnage, and for container ships, it is 70% of the DWT. The total DWT is used as capacity for other types.\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\"\u003e\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({f}_{i},{f}_{1},{f}_{w},{and f}_{c}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\"\u003e\u003cp\u003eThe correction factor for specific ship types. \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({f}_{w}\\)\u003c/span\u003e\u003c/span\u003e is a non-dimensional factor that considers weather and environmental conditions and is calculated using Eq:\u003c/p\u003e\u003cp\u003e.\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({f}_{w}=0.0208*\\text{ln}\\left(Capacity\\right)+0.633\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/table\u003e\u003cp\u003e\u003cstrong\u003e2. Economic analysis methodology\u003c/strong\u003e\u003c/p\u003e\u003cp\u003eThe economic analysis for using methanol or natural gas as a dual fuel evaluated by calculate the reduction of ship emissions annual cost-effectiveness E\u003csub\u003eCE\u003c/sub\u003e. This includes the annual capital cost reduction (ACC) of using alternative fuels onboard and the conversion process in $/ton, the maintenance and operation costs (AMC), and the amount of emission reduction (RE) in tons/year, as shown in Eq (Ammar and Seddiek \u003cspan class=\"CitationRef\"\u003e2020b\u003c/span\u003e):\u003c/p\u003e\u003cdiv class=\"Equation\"\u003e\u003cdiv class=\"mathdisplay\" name=\"EquationSource\"\u003e$${EAC}_{CE}=\\frac{ACC+AMC}{RE}$$ 15\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Case Study: Container Ship","content":"\u003cp\u003eIn this study, A13-class container ship was selected to study the environmental and economic impacts assessment process from using alternative fuels instead of diesel fuel (Ammar and Seddiek \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2020a\u003c/span\u003e). The container vessel AL RIFFA, which is owned by a United Arab shipping company and operated by Hapag-Lloyd, Hamburg, was built in 2017 with 13500 containers and sailing under Malta flag. Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e3\u003c/span\u003e depicts the ship's critical data (Al Riffa 2022). The ship operated with a slow speed diesel engine that uses marine diesel (0.1S%) to move cargo between several ports in the United States of America, the Mediterranean and the Middle East region with a maximum continuous rating of 74255.5 kW. The relation between the specific fuel consumption and MCR can be used to calculate SFC (El Gohary and Abdou 2011). For 85%MCR, SFC is 169.1 (g/kwh). As shown in Table \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e3\u003c/span\u003e, for low-speed diesel engines, the emission factors are 17 g/kWh, 0.36 g/kWh, 688.79 g/kWh, 0.19 g/kWh, 1.4 g/kWh, and 0.6 g/kWh for NOx, SOx, CO2, PM, CO, and HC, respectively. Both NOx and SOx emissions are incompatible with current IMO limitation as IMO 2016 regulation reduced NOx emissions to less than 3.4 g/kWh and IMO 2020 regulation limited SOx to 0.5%. For this, the conversion process from using marine diesel fuel to dual fuel operated by alternative fuels (Methanol and natural gas) were evaluated to study its effect on marine pollution.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe container ship case study's primary dimensions\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpecifications\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eA 13\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eShip\u0026rsquo;s Name\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAl Riffa\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYear built\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2012\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIMO No.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9525912\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFlag\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMalta\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLength over all (m)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e366\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eL.P.P, (m)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e350\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBreadth over all (m)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e48\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpeed (kn)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePower (kw)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e71770\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTEU\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13470\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDeadweight (tdw)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e145528\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGross Tonnage (GRT)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e141077\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDisplacement (ton)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e187974.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMain engine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMAN B\u0026amp;W 12K98ME\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWaste Heat Recovery (KW)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1818 T/G\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eShaft Generator [PTI/PTO] (KVA/KW)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3222/2578\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLength of trip\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20600 N.M\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe ship is currently powered by MAN B\u0026amp;W 12K98ME engine with an output of 48,280 KW at 104 rpm, and operated with marine diesel oil MDO (0.1% S). The length and high of the engine are 29 m and 14.6 m; the bore is 980 mm, and the stroke is 2660 mm. For each trip, load factors for are 85% during cruise, 20% in maneuvering, and 5% at standby modes. The main engine provides with three auxiliary engines (AE), rated 4,250 kW for each engine. Additional shaft generator connects with engine shaft to produce 2,578 KW for the electricity power. The study aims to convert the main engine into a dual fuel engine by preparing the cylinder head with two conventional valves for the pilot fuel and alternative fuels. Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e4\u003c/span\u003e illustrates the main properties of methanol and natural gas.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison between methanol, diesel, and natural gas properties\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProperties\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDiesel\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNatural gas\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMethanol\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBoiling Point\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e320\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-161.5 \u003csup\u003eo\u003c/sup\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e83.189 \u003csup\u003eo\u003c/sup\u003eC\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFreezing point\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-182.6 \u003csup\u003eo\u003c/sup\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-97.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOctane Number\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e120 \u0026sim; 130\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e109 \u0026sim; 114\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFlame speed (m/s)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.867\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.445\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRelative Density\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.8 \u0026sim; 0.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.72 \u0026sim; 0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.787 \u0026sim; 0.792\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCarbon content\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e86.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e37.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHydrogen content\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOxygen content\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLatent Heat\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e250 kj/kg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e510 kj/kg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1062.2 kj.mol\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpecific Gravity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.43 \u0026sim; 0.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.896 \u0026sim; 0.91\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFlammability limits\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.6 \u0026sim; 5.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 \u0026sim; 15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6 \u0026sim; 36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIgnition Temperature\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e355 \u003csup\u003eo\u003c/sup\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e538 \u003csup\u003eo\u003c/sup\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e470 \u0026sim; 500 \u003csup\u003eo\u003c/sup\u003eC\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Results And Discussion","content":"\u003cp\u003eThe current study is primarily concerned with compare between the effects of using natural gas and methanol as an alternative fuel in a dual-fuel engine on the container ship. Firstly, the emission rates (SOx, NOx, and CO2) per trip were evaluated to assess the environmental performance of using methanol and natural gas. The emissions rates are compared based on IMO limitation. Secondly, energy efficiency design index EEDI and energy efficiency operational indicator EEOI are calculated to evaluate the CO2 emission and compare with IMO requirements at different phases. Finally, the impact of using natural gas and methanol on cost-effectiveness is measured.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.1 Emission assessment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo begin, the reduction effect of using natural gas and methanol as a dual fuel on emissions factors such as SOx, NOx, CO2, PM, CO, and HC was measured. Figure 5 illustrates the emission rates of using 95% dual fuel at (g/kwh). CO2 emission is reduced from 688.7 g/kwh to 555.23 g/kwh when using (95% NG and 5% MDO), and to 295.69 g/kwh when using (95% ME and 5% MDO). The methanol dual fuel decreased NOx emissions from 17 to 3.19 g/kwh, however, there was a slight increase compared to 2.902 for natural gas dual fuel. Both SOx and PM achieved maximum reduction for using dual fuel with ratios of 95% and 97.36%, respectively. HC emissions increased by using dual fuel from 0.6 g/kwh to 1.36 g/kwh and 0.9044 g/kwh for natural gas and methanol, in the order.\u003c/p\u003e\n\u003cp\u003eNOx emissions are assessed by comparing them with the IMO limitation. According to IMO 2016 limitations, the NOx emission rate is based on engine speed and equals 3.5549 g/kwh. Figure 6 describes the reduction effect of using methanol and natural gas as a dual fuel compared with diesel fuel on NOx emissions. Using diesel fuel is not matching with IMO 2016 regulation, and with increase the ratio of methanol dual fuel and natural gas dual fuel, the NOx emission reduced to 2.6153 g/kwh and 2.3084 g/kwh, respectively. According to Fig.6, using natural gas dual fuel with ratio above 91% NG or Methanol with ratio above 93% ME will be compliant with the new IMO requirements. For Sox emissions, IMO 2020 imposed new requirements for fuel oil used on board ships should not exceed 0.5% sulfur that equals 0.0857 ton/hr. There was a similarity for using dual fuel by natural gas or methanol, which reduced the SOx rate to 0.0001738 ton/hr with (99% NG and 99% ME), as shown in Fig.7. It is now necessary to calculate the total emission per trip and the annual emission for each emission factor. For this, a dual fuel engine with 98% natural gas and 98% methanol was used to evaluate the emission factor, as shown in Table \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e. The load factor during maneuvering and standby mode was taken into consideration. It can be noticed the difference between emission factors during operation, maneuvering, and standby modes. Methanol dual fuel engine emits less SOx, CO2, and PM emissions better than natural gas; however, there is a slight increase in NOx emission. According to United Arab Shipping Company data, the Al Riffa container ship makes 6 trips per year at a rate of 49 days per trip. This equates to 295 days per year. By using Eq. (1), the total emission per trip and annual emission were calculated to assess the environmental effect from using a dual fuel engine. Table \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e illustrates the total reduction in emissions achieved by using a dual fuel engine. Using 98% natural gas dual fuel reduced the annual NOx, CO2, SOx, PM, and CO pollution by 85.55%, 20%, 98%, 98%, and 33.60%, respectively, while, using 98% methanol dual fuel recorded a reduction ratio by 83.76%, 58.87%, 98%, 98%, and 60.20%in the order. However, HC pollution increased for each dual fuel.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" id=\"Tab4\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003etype of emission\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eemission factor (g/kwh)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eemission rate during operation (kg/hr.)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eemission rate during maneuvering (kg/hr.)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eemission rate during standby (kg/hr.)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003ethe emission factor during, operation, maneuvering, and standby by using natural gas or methanol dual fuel\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"6\"\u003e\n \u003cp\u003e\u003cstrong\u003e98% Natural gas (NG) dual fuel\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNOx\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.4568\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e132.8313\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e31.25443\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7.813607\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSox\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0072\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.389281\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.091596\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.022899\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCO2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e551.0118\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e29791.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7009.752\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1752.438\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0038\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.205454\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.048342\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.012086\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9296\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e50.2605\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11.826\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.9565\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.384\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e74.82845\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17.60669\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4.401674\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"6\"\u003e\n \u003cp\u003e\u003cstrong\u003e98% Methanol (ME) dual fuel\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNOx\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.7606\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e149.2568\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35.11925\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8.779812\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSox\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0072\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.389281\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.091596\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.022899\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCO2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e283.2758\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15315.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3603.721\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e900.9304\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0038\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.20545384\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.04834208\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.01208552\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.5572\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e30.12602\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7.088476\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.772119\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.91409\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e49.42192\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11.62869\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.907172\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" id=\"Tab5\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eemission\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFuel type\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eEmission ton /trip\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eEmission ton /year\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eReduction ton/year\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e% Of reduction / year\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eEnvironmental analysis of the Al Riffa container ship.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"3\"\u003e\n \u003cp\u003eNOx\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDiesel fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1408.680\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8429.770\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNG dual fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e203.145\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1218.251\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7211.519\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e85.55%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eME dual fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e228.266\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1368.896\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7060.874\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e83.76%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"3\"\u003e\n \u003cp\u003eSox\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDiesel fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e29.767\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e178.510\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNG dual fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.595\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.570\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e174.940\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e98.00%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eME dual fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.595\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.570\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e174.940\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e98.00%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"3\"\u003e\n \u003cp\u003eCO2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDiesel fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e56954.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e341549.500\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNG dual fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e45561.529\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e273229.607\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e68319.893\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e20.00%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eME dual fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e23423.234\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e140467.655\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e201081.845\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e58.87%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"3\"\u003e\n \u003cp\u003ePM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDiesel fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15.710\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e94.215\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNG dual fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.314\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.884\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e92.331\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e98.00%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eME dual fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.314\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.884\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e92.331\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e98.00%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"3\"\u003e\n \u003cp\u003eCO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDiesel fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e115.762\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e694.216\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNG dual fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e76.866\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e460.960\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e233.256\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e33.60%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eME dual fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e46.073\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e276.298\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e417.918\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e60.20%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"3\"\u003e\n \u003cp\u003eHC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDiesel fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e49.612\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e297.521\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNG dual fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e114.439\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e686.283\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e-388.762\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e-130.67%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eME dual fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e75.583\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e453.269\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e-155.748\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e-52.35%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e4.2 Energy efficiency assessment\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBased on IMO requirements, evaluated, the EEDI is the most effective way to assess the energy efficiency of a ship. As mentioned, there are two values of EEDI, required values that can be calculated by Eq. (7), where X is the reduction percentage and increased from 10% in 2015 to 30% in 2025, as shown in Fig. 8. The required EEDI for the Al-Riffa ship, which was built in 2012, is 15.971 gCO2/ton-nm at the DWT 145528 ton. According to IMO, this value should be reduced to 20% at phase 2 and equal 12.777 gCO2/ton-nm. Another value is the attained EEDI, which is calculated using Eq. 8, and then compare this value with required EEDI in phase 2. Based on IMO regulations, the service speed (23 kn) can be used as a reference velocity (V\u003csub\u003eref\u003c/sub\u003e), and 70% DWT is considered as a ship capacity. The actual EEDI is 14.83 gCO2/ton-NM; this value reduced from required EEDI with ratio 7.14%, which is lower than the required EEDI, but will be incompatible with phase 2 from 2020 to 2025, as shown in Fig. 9. The reduction effects from using natural gas and methanol as a dual fuel engine were evaluated for variable ratios (70%, 80%, 90%, and 95%) to find the best percentage of dual fuel that achieves the required EEDI. Fig. 10, illustrates the reduction values from using natural gas and methanol as a dual fuel. The actual EEDI reduced from 11.27 g.CO2/ton. NM at 70% NG dual fuel to 10.827 g.CO2/ton. NM at 95% NG dual fuel, while methanol dropped to 8.362 g.CO2/ton. NM at 95% ME dual fuel. Both of dual fuels complicated with IMO regulation.\u003c/p\u003e\n\u003cp\u003eEnergy Efficiency Operational Indicator (EEOI) is another method adopted by IMO to measure the energy efficiency of the ships and carbon emissions during operations. According to Eq. (14), the EEOI is calculated based on the distance traveled, the transported TEU cargo, and the amount of fuel consumed per trip. For A13 class container ship, theTEU cargoes transported are 13500, over distance 20600 nautical miles. Figure 11 shows that the EEOI during operation is reduced from 0.00017 to CO2/TEU-NM when use MDO to 0.000146 tonCO2/TEU-NM and 0.000077 tonCO2/TEU-NM when use 95% NG and 95% ME, respectively. The calculations for maneuvering and standby were carried out based on 20% and 5% fuel consumption, in order.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3 Economic assessment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe economic impact of converting the diesel engine into a dual fuel engine was examined in this section, and the cost-effectiveness of reducing ship NOx, CO2, and CO emissions by using natural gas and methanol was assessed. In terms of capital cost, to calculate the annual fuel cost, it is important to evaluate the total fuel consumption in the case of using diesel fuel and dual fuel, as shown in Table \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e. Because marine diesel fuel and alternative dual fuels are so similar, using natural gas or methanol requires only minor changes to diesel fuel infrastructure. As a result, the cost of bunkering facilities for diesel fuel and dual fuel is assumed to be the same in this study. The calculations are based on diesel, natural gas, and methanol fuel costs of 1320.8 \u003cspan\u003e$\u003c/span\u003e/m3, 684.2 \u003cspan\u003e$\u003c/span\u003e/m3, and 528.34 \u003cspan\u003e$\u003c/span\u003e/m3, in addition to 8.0 \u003cspan\u003e$\u003c/span\u003e/m3 for the bunkering prices (Afdc 2022). Table \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e illustrates the annual fuel cost for diesel fuel and dual fuel (natural gas or methanol)\u0026nbsp;\u003c/p\u003e\u0026nbsp;\u003ctable border=\"1\" id=\"Tab6\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eAl Riffa container ship main engine fuel consumptions.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFuel consumption (m3)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ediesel engine\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eDual fuel engine with 90% Natural gas\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eDual fuel engine with 90% Methanol\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMDO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNatural gas\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMDO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMethanol\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMDO\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eper trip\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17,280\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20,753\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1,900\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30,226\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1,900\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eper year\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e103,632\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e124,941\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11,400\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e181,267\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11,400\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003e\u003c/p\u003e\u0026nbsp;\u003ctable border=\"1\" id=\"Tab7\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 8\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eFuel consumption annual cost for diesel and dual-fuel engine\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ecost item\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003ePrices in (millions US\u003cspan\u003e$\u003c/span\u003e/year)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ediesel engine\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNG-dual fuel engine\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eME-dual fuel engine\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDiesel fuel\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e136.877\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15.057\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15.057\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDiesel bunkering\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.829\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.0912\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.0912\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNatural gas\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e85.485\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNatural gas bunkering\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMethanol\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e95.771\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMethanol bunkering\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.45\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003etotal fuel cost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e137.706\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e101.6332\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e112.3692\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003eFor conversion cost from the main engine to a dual fuel engine, it is expected to be 10.72 million dollars with 285 \u003cspan\u003e$\u003c/span\u003e/kW conversation rate (Andersson and Salazar \u003cspan class=\"CitationRef\"\u003e2015\u003c/span\u003e; Stefenson \u003cspan class=\"CitationRef\"\u003e2014\u003c/span\u003e). For operation and maintenance costs, according to data collected, the total operation and maintenance cost is 714749 \u003cspan\u003e$\u003c/span\u003e/years (Banawan et al., \u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e). Now, the total cost-effectiveness calculated for each emission type based on the added annual cost of the conversion process as discussed by using Eq. (15). Fig. 12, shows the annual cost-effectiveness of the proposed dual-fuel engine in reducing ship emissions for the container ship.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe International Maritime Organization (IMO) highlighted various methods for lowering ship exhaust emissions and improving marine energy savings from both operational and technical perspectives. One of the effective long-term measures for reducing emissions and improving energy efficiency which presented in this paper is converting from using fossil fuel in a conventional diesel engine to a dual fuel engine operating with alternative fuels. Natural gas and methanol are becoming more appealing as alternatives to traditional marine fuels. This study provided a comparative analysis of using methanol or natural gas to achieve the best solution in a dual fuel engine in terms of environmental performance. Furthermore, the economics of using alternative fuels instead of marine diesel oil are discussed. The analysis' findings revealed the following:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eFrom an environmental standpoint, the analysis results show that using natural dual fuel engines with ration (95%NG and 5% MDO) reduces NOx, SOx, CO2, PM, CO emissions by 83%, 95%, 19.4%, 95%, and 32.6%, respectively. On the other hand, the emissions saved percentage by using 95% methanol as a dual fuel is 81.2%, 95%, 57.1%, 95%, and 58.4%, respectively. Moreover, converting a conventional diesel engine to a dual fuel engine powered by natural gas or methanol as an alternative fuel will comply with IMO 2016 and 2020 emission requirements for NOX and SOx with marine diesel oil percentages less than 10%.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFrom energy efficiency point of view, according to energy efficiency design index EEDI techniques, the dual fuel engine powered by (95% NG and 5% MDO) or (95% ME and 5% MDO) will meet IMO requirements. The required EEDI value for the third phase was 11.81 gCO2/ton-NM, and the attained EEDI value when using natural gas and methanol in a dual fuel engine was 10.827 g.CO2/ton and 8.362 g.CO2/ton-NM, respectively. Furthermore, using 95% natural gas or 95% methanol satisfies not only current IMO EEDI requirements but also future ones.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eIn terms of cost-effectiveness, the suggested dual-fuel (95% NG\u0026thinsp;+\u0026thinsp;5% MDO) engine will reduce NOx, SOx, CO2, PM, and CO emissions while saving 769.25 \u003cspan\u003e$\u003c/span\u003e/ton, 3304.1\u003cspan\u003e$\u003c/span\u003e/ton, 81.2 \u003cspan\u003e$\u003c/span\u003e/ton. 60082.64 \u003cspan\u003e$\u003c/span\u003e/ton, and 23782.84 \u003cspan\u003e$\u003c/span\u003e/ton, respectively. in addition to 850.67 \u003cspan\u003e$\u003c/span\u003e/ton, 3340.1\u003cspan\u003e$\u003c/span\u003e/ton, 45.588 \u003cspan\u003e$\u003c/span\u003e/ton, 55450.87 \u003cspan\u003e$\u003c/span\u003e/ton, and 13274.11 \u003cspan\u003e$\u003c/span\u003e/ton, in the order, when using dual-fuel (95% ME\u0026thinsp;+\u0026thinsp;5% MDO) engine.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding: -\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests: -\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions: -\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Mahmoud Abdel Nasser, Mohamed M. Elgohary, Mohamed Shouman and Majed Abdelnabi. The first draft of the manuscript was written by Mahmoud Abdel Nasser and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Approval\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Publish\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they are approved to Publish the paper with title \u0026quot; Environmental and economic performance investigation of natural gas and methanol as a marine alternative fuel.\u0026quot; to \u0026quot;Environmental Science and Pollution Research\u0026quot; journal.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Participate\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they are agreeing to participate the scientific data of the paper with \u0026quot;Environmental Science and Pollution Research\u0026quot; journal\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they are approve to available any data and materials that relate with the paper. \u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eA.G. 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Transp Res Part D Transp Environ 17:478\u0026ndash;486. https://doi.org/10.1016/j.trd.2012.05.010\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Ship emission reduction, Natural gas, Dual fuel engine, Methanol, IMO regulations","lastPublishedDoi":"10.21203/rs.3.rs-1947354/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1947354/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eEmissions from ships are a serious global issue due to their effects on environmental damage, particularly global warming of the atmosphere. As a result, the International Maritime Organization (IMO) places a high priority on environmental protection by reducing exhaust emissions by at least 50% by 2050. Among the IMO's proposed measures, using alternative marine fuels such as natural gas and methanol instead of conventional fuels has been prioritised. In this paper, a comparative study between convert diesel engine into dual fuel engine operated with alternative fuels such as methanol or natural gas is carried out. Environmental and economic assessment of the natural-dual fuel engine and methanol- dual fuel engine is conducted. A13-class container ship is investigated as a case study. The evaluation results show that using natural gas in a dual fuel engine with a percentage (95% NG and 5% MDO) reduces NOx, SOX, CO2, PM, and CO pollutions by 83%, 95%, 19.4%, 95%, and 32.6%, respectively, while the emissions percentage will be 81.2%, 95%, 57.1%, 95%, and 58.4%, in order, when using methanol as a dual fuel with percentage 95% Methanol. Moreover, the cost-effectiveness of using natural gas was 769.25 \u003cspan\u003e$\u003c/span\u003e/ton, 3304.1\u003cspan\u003e$\u003c/span\u003e/ton, 81.2 \u003cspan\u003e$\u003c/span\u003e/ton. 60082.64 \u003cspan\u003e$\u003c/span\u003e/ton, and 23782.84 \u003cspan\u003e$\u003c/span\u003e/ton for NOx, SOx, CO2, PM, and CO, in the order, while for methanol, was 850.67 \u003cspan\u003e$\u003c/span\u003e/ton, 3340.1\u003cspan\u003e$\u003c/span\u003e/ton, 45.588 \u003cspan\u003e$\u003c/span\u003e/ton, 55450.87 \u003cspan\u003e$\u003c/span\u003e/ton, and 13274.11 \u003cspan\u003e$\u003c/span\u003e/ton, respectively.\u003c/p\u003e","manuscriptTitle":"Environmental and economic performance investigation of natural gas and methanol as a marine alternative fuel.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-09-07 13:48:41","doi":"10.21203/rs.3.rs-1947354/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"8bdec043-89ed-47db-aced-1487f11ab3e0","owner":[],"postedDate":"September 7th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2022-11-28T16:19:42+00:00","versionOfRecord":[],"versionCreatedAt":"2022-09-07 13:48:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1947354","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1947354","identity":"rs-1947354","version":["v1"]},"buildId":"J0_U0BvcaRcwD8yVFaRlm","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}