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1、DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS TECHNICAL AND OPERATIONAL ADVISORYAPRIL 2025TABLE OF CONTENTSWhile ABS uses reasonable efforts to accurately describe and update the information in this publication,ABS makes no warranties or representations as to its accuracy,currency,or completeness.ABS ass

2、umes no liability or responsibility for any errors or omissions in the content of this publication.To the extent permitted by applicable law,everything in this publication is provided“as is”without warranty of any kind,either expressed or implied,including,but not limited to,the implied warranties o

3、f merchantability,fitness for a particular purpose,or noninfringement.In no event will ABS be liable for any damages whatsoever,including special,indirect,consequential,or incidental damages or damages for loss of profits,revenue or use,whether brought in contract or tort,arising out of or connected

4、 with this publication or the use or reliance upon any of the content or any information contained herein.EXECUTIVE SUMMARY .1Overall Considerations .1Key Points to Consider .2What to Look For .3Conclusion .3INTRODUCTION .4NEWBUILD SPECIFICATION .5DF LNG Vessel .7DF Methanol Vessel .12DF Ammonia Ves

5、sel .17REGULATORY CONSIDERATIONS .23IDG Code .23ABS Rules and Requirements .25Emmissions Compliance .26Cost of Compliance .29CONCLUSION .34ACRONYMS AND ABBREVIATIONS .37EXECUTIVE SUMMARYThe maritime industry faces increasing regulatory pressure to decarbonize,driven by the International Maritime Org

6、anization(IMO)emission reduction targets and the European Union(EU)maritime emission regulations.Shipowners are exploring different dual-fuel(DF)propulsion options as a pathway to reduce greenhouse gas(GHG)emissions and to support future-proofing their assets against upcoming regulations.This adviso

7、ry provides a comprehensive examination of DF propulsion options for a newbuild vessel.These DF solutions typically include traditional hydrocarbon-based fuel and an alternative fuel(such as liquefied natural gas LNG,liquefied petroleum gas LPG,methanol,etc.).This publication will focus on LNG,metha

8、nol and ammonia as potential alternative fuels only,as alternatives such as LPG and ethane are considered specialized(for LPG and ethane carriers respectively)short-term solutions,as green alternatives for these fuels are not expected to be developed.OVERALL CONSIDERATIONSFUEL OPTIONSLNGIt is curren

9、tly the most mature fuel solution;offering significant emissions reductions compared to conventional marine fuels.In addition,biogas(BioLNG)has the same chemical composition as LNG and is a drop-in fuel in LNG systems.However,challenges include the complexity of fuel containment systems,high costs,a

10、nd methane slip,which could limit long-term compliance with stringent emissions regulations.In the short term,using a green version of LNG(biogas or synthetic LNG)for LNG carriers will be more challenging because they usually burn the cargo they carry.MethanolMethanol is emerging as a viable alterna

11、tive for the marine industry due to its lower carbon footprint and simpler onboard handling.Similarly to LNG,the green versions of methanol(biomethanol and synthetic methanol)can easily be used as drop-in fuels in methanol systems.The existing infrastructure for methanol bunkering(based on its wide

12、use in the chemical industry and the large volume shipped around the world)is a benefit,but its lower energy density and high flammability require careful management and additional safety measures.AmmoniaAmmonia is a promising carbon-free fuel,but its adoption faces significant hurdles related to to

13、xicity and handling.Despite these challenges,ammonias potential for near-zero emissions makes it a key contender for future-proofing against ever more stringent GHG reduction regulations.Green ammonia can be produced without the need for biogenic carbon.This is a significant advantage compared to th

14、e other fuels.Similarly to LNG and methanol,blue and green ammonia is a drop-in fuel for ammonia systems on board ship.CH3OHNH3DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 1REGULATORY LANDSCAPEThe industry is transitioning from conventional Tank-to-Wake(TtW)emissions evaluations to a Well-to-Wake(WtW)ap

15、proach,accounting for the entire life-cycle emissions of fuels.This shift demands that shipowners consider alternative fuels that can meet both current and future regulatory standards,such as the IMOs Revised Strategy and the relevant elements of EUs Fit for 55 legislative package(e.g.,EU Emission T

16、rading Scheme(EU ETS),FuelEU Maritime,etc.).ECONOMIC AND OPERATIONAL IMPLICATIONSEconomic analysis suggests that while DF LNG and DF methanol vessels have higher initial investment costs,they offer varying levels of regulatory compliance and operational cost savings over time.Ammonia,though currentl

17、y less developed,could provide substantial long-term compliance benefits due to its near-zero GHG emissions potential.The choice of fuel impacts not only the design and construction of vessels but also their operational efficiency,safety and long-term viability in a decarbonizing industry.The key de

18、cision factors that shipowners should consider are:Fuel Infrastructure Availability:Is the supply chain ready to support the fuel choice?Regulatory Compliance:How does the fuel align with evolving IMO and EU requirements?Operational Impact:What are the implications for vessel range,efficiency and sa

19、fety?Economic Feasibility:What are the upfront costs vs.long-term savings?KEY POINTS TO CONSIDERBASIC DESIGN CONSIDERATIONSFuel Containment SystemsFuel Supply Systems(FSS)Machinery Space ConceptDetermine the most suitable fuel containment system(Type A,B,C or membrane for LNG;appropriate tanks for m

20、ethanol and ammonia)based on vessel design,space availability and operational profile.Consider the implications of tank type on safety,cost and operational complexity.Specify the design requirements for the FSS,considering the need for redundancy,pressure management and compatibility with the select

21、ed fuel.Investigate the integration of safety measures such as double-walled piping,inert gas systems and appropriate venting solutions.The non-hazardous machinery space concept should be chosen to minimize complexity and cost,especially considering the high toxicity of ammonia.2DUAL-FUEL SOLUTIONS

22、FOR NEWBUILD VESSELSWHAT TO LOOK FOR Regulatory Compliance:The vessels design and fuel systems meet the latest IMO and EU regulatory requirements,particularly regarding GHG emissions and safety.An important element is the gradual shift to WtW emissions which highlights the need to consider the selec

23、tion of the fuel under the life-cycle perspective.Operational Impact:Assess the impact of the selected DF system on the vessels operational efficiency,including fuel availability,infrastructure readiness,availability of skilled crew and the potential for reduced cargo capacity due to larger fuel tan

24、ks.Technology Maturity:Examine the technological readiness level of each fuel option.Liquefied natural gas is the most mature,methanol use in main engines,FSS and tanks are mature as well,while ammonia presents emerging but less proven alternatives.The first ammonia-fueled oceangoing ship will be go

25、ing into service around the beginning of 2026.Evaluate the reliability and service experience of engines and FSS for each fuel.CONCLUSIONChoosing the right DF propulsion system for a newbuild vessel requires balancing:Future regulatory compliance(EU ETS,FuelEU Maritime,IMO GHG Fuel Standard GFS)Fuel

26、 availability and infrastructure readiness Operational flexibility and safety considerations Long-term economic viabilityLiquefied natural gas offers immediate benefits due to its maturity and established infrastructure,with methanol and ammonia presenting promising alternatives with distinct challe

27、nges related to safety and handling,while offering greater compliance flexibility and sustainability in the long run.Each fuel option carries its own set of challenges and advantages,and the optimal choice will depend on specific operational profiles,regulatory environments and the owners long-term

28、strategic goals.WHERE TO PAY ATTENTIONSafety ConsiderationsCorrosion and Material CompatibilityMachinery Space ConceptFocus on the safety systems associated with each fuel,such as gas detection,fire suppression and emergency shutdown systems.Pay special attention to the design of machinery spaces,bu

29、nkering stations and ventilation systems to comply with the International Code of Safety for Ships Using Gases or other Low-Flashpoint Fuels(IGF Code)and the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk(IGC Code).For methanol and ammonia,all materia

30、ls in contact with these fuels are to be resistant to corrosion.Specify the use of stainless steel,special coatings or compatible non-metallic materials where necessary.The design should facilitate efficient and safe bunkering operations,considering the need for vapor return systems,pressure control

31、 and compatibility with bunker vessels.Evaluate the implications of bunkering on operational schedules and routes.3DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELSINTRODUCTIONABS is committed to being a recognized leader for new technology development and assessment,and for serving as a trusted technical ad

32、visor to the marine industry.These pillars have formed the foundation for the success of ABS for more than 160 years,and,more importantly,position the organization to provide the practical solutions needed for the future.Positioned around the world,the ABS team has the experience,knowledge and profe

33、ssional judgment to assist our members and clients in developing their marine projects worldwide.Spurred by the International Maritime Organizations(IMO)emissions reduction targets,and European Union(EU)maritime emissions regulations,the industry continues to face increased pressure to decarbonize,c

34、reating new challenges across the maritime value chain.Ship emissions have become an increasingly important factor to vessel owners,both air emissions and discharges to the sea.The mounting regulatory pressure combined with charterers making decisions regarding which vessels to charter and ports pro

35、viding incentives for cleaner vessels has led to the need for more involved solutions for reducing emissions.Traditionally,only Tank-to-Wake(TtW)emissions,the emissions generated on board the vessel from the combustion of the fuel,were considered.This is no longer the case,with upcoming regulations

36、such as the FuelEU Maritime and the IMO greenhouse gas(GHG)Fuel Standard(GFS)considering the full life cycle of the fuel,that is,both fuel production emissions Well-to-Tank(WtT)and shipboard combustion TtW emissions,the Well-to-Wake(WtW)approach.To satisfy these regulations,conventional improvement

37、options,such as low-friction coatings,propulsion improvement devices and machinery efficiency improvements will no longer be sufficient.A change of fuel is one of the solutions that must be considered.This advisory outlines the key factors requiring attention when considering dual-fuel(DF)vessels.Th

38、ese include design aspects(usually reflected in a new build specification),critical aspects relating to the selection of the DF engine and operational aspects that require consideration.In addition,regulatory and economic considerations are also presented.4DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELSNEW

39、BUILD SPECIFICATIONApplying alternative fuels in newbuild vessels offers significant benefits for reducing emissions but also introduces specific challenges.The adoption of alternative fuels requires a solid understanding of the associated risks,not only for vessel safety but also for the safety of

40、all personnel involved in the ships operations.The following sections will focus on implementation of liquefied natural gas(LNG),methanol and ammonia as marine fuel for newbuilds from a technical perspective.However,it is important to highlight that the success of these efforts depends on the workfo

41、rces expertise in handling these fuels.Crew members must be qualified and certified for working on board vessels using alternative fuels.Therefore,training programs must continuously evolve to keep up with technological advancements and regulatory updates.The main challenges and characteristics asso

42、ciated with each fuel include:Flammability and explosion risks Toxicity Material compatibility,reactive and corrosive behaviors Environmental impact Specific fuel properties(lower calorific value LCV,energy density)Table 1 provides an overview of the basic fuel properties in comparison with the conv

43、entional option of marine gas oil(MGO).FuelBoiling Point(C)at 1 bar(a)LiquidDensity(kg/m3)LCV (MJ/kg)FlammableRange(%vol in air)EnergyDensity(MJ/L)VolumeComparisonwith MGOMGO3608545.91-839.21LNG-16342848.65-1520.61.9Methanol6579019.96-3615.72.5Ammonia-3368218.815-2812.83.1Table 1:Fuel properties.Liq

44、uefied natural gas is currently used as fuel across various types of vessels.Extensive experience deriving from LNG carriers and LNG bunkering infrastructure has reached a level of maturity with numerous LNG bunker vessels operating worldwide.Technology,especially regarding containment systems and e

45、ngines,is also mature,having been developed and refined over the years.Challenges associated with LNG include the complexity of some containment systems,fuel gas supply systems(FGSS)and the effective management of high levels of boil-off gas(BOG).Methanol is a widely shipped chemical,and there is ex

46、perience with transportation on ships as cargo and available infrastructure that can easily be developed to support bunkering ships.Methanol engines,developed by major manufacturers,have demonstrated proven reliability in operation.Methanol is a liquid in ambient conditions,making handling and onboa

47、rd containment much simpler than LNG or other liquefied gaseous fuels.If mishandled,methanol can be toxic,with the potential to cause serious health issues such as blindness or death if ingested.Its toxicity is critical not only through ingestion but also via inhalation or skin contact.It is a highl

48、y flammable liquid with a large flammability range(6 to 36 percent volume in air),low flashpoint(11 C)and high heat of vaporization.Methanol-water mixture with over 25 percent can still be flammable.Methanol flames are nearly invisible without producing smoke and can be undetected at initial stages.

49、Methanol causes corrosion;therefore,carbon steels need a special coating to be protected or stainless steel to be used.Non-metallic materials used in fuel tanks and pipes are to consist of appropriate methanol-compatible materials,such as nylon,neoprene or non-butyl rubber.5DUAL-FUEL SOLUTIONS FOR N

50、EWBUILD VESSELSAmmonia is a promising fuel due to its carbon-free compound.However,due to toxicity,it poses serious health risks at low concentrations and can be fatal at higher levels if not properly handled.Given its high toxicity to aquatic life,spills may significantly affect the marine ecosyste

51、m.The severity of these impacts depends on factors such as concentration and duration of the spill,as well as water temperature,pH,and salinity.It is readily soluble in water,where it acts as a base forming the ammonium ion NH4+,which is less harmful to organisms compared to ammonia.The ratio of NH4

52、+and ammonia in water depends on temperature,salinity and pH level.In open seawater,ammonia will evaporate from the upper layers of the water column and will not affect the lower water column layers.Recent studies show that ammonia may cause adverse effects,including death,to sensitive species or in

53、dividual organisms in an open sea during the first day after the spill.Thereafter,the sea environment starts to recover.Due to its pungent smell,ammonia can be detected well below 25 parts per million(ppm),which is an early warning signal.Introducing this toxic fuel presents new challenges related t

54、o safe bunkering,storage,supply and consumption.A ships design is affected,as the release of ammonia should be mitigated in all cases.Toxic areas should be determined upon an ammonia gas dispersion analysis.While less likely to ignite in open air due to its flammable range(15 to 28 percent volume in

55、 air)and rapid diffusion,ammonia presents a significant ignition risk in confined spaces,especially in the presence of oil and other combustibles.Storage tanks may also be at risk of explosion under high heat.Ammonia requires refrigeration at-33 C to remain a liquid at atmospheric pressure.Exposure

56、to higher temperatures can lead to brittle fractures in containment materials and frostbite risks from evaporating ammonia.Ammonias reaction with various materials can lead to significant integrity issues.It should not contact mercury,copper,copper-bearing alloys and zinc to avoid corrosion.Interact

57、ion with carbon dioxide(CO2)can form carbamates,leading to clogs and damage in the fuel system.Oxygen presence can accelerate stress corrosion cracking in steels at high temperatures.6When considering the design of LNG-fueled ships,several systems need to be integrated into the vessel that are diffe

58、rent,or additional,to conventional ship designs.These include the LNG fuel containment system,LNG bunker station and transfer piping,FGSS,the double-wall fuel gas distribution piping,gas valve unit(GVU),gas consumers,nitrogen generating plant,vent piping systems and mast(s),and depending on the LNG

59、tank type,additional equipment for managing tank temperatures and pressure.Figure 1:Installations on board new-build DF LNG ship.The protective LNG tank location criteria can be based on a deterministic approach considering tank volume or a probabilistic method.The International Code of Safety for S

60、hips Using Gases or other Low-Flashpoint Fuels(IGF Code)provides a third alternative,where the ships hull is specifically designed and reinforced in the way of the LNG tank,therefore minimizing the impact from a collision and allowing the tank to be closer to the ships side shell.FUEL CONTAINMENTThe

61、re are four main types of LNG tanks:independent tank types A,B and C,and integrated membrane tanks.Types A,B and membrane are low-pressure,nominally atmospheric tanks,whereas Type C are pressurized tanks.Type A,B and membrane tanks require a secondary barrier for protection in case of a leak from th

62、e primary barrier.Type A and membrane systems require a full secondary barrier.Type B requires a partial secondary barrier since these are designed using advanced fatigue analysis tools and a leak before failure concept,for which small leaks can be managed with partial cryogenic barrier protection a

63、nd inert gas management of the interbarrier space.Type C tanks are designed using pressure vessel code criteria and conservative stress limits.Therefore,they do not require a secondary barrier.Most gas fueled ships in operation have the IMO Type C pressurized fuel tanks.This is because these are rel

64、atively inexpensive to manufacture and simple compared to the other fuel containment types,particularly in the smaller sizes required by the current gas fueled fleet.Type C tanks can also simplify the required BOG management equipment because of their pressure accumulation capability.However,these t

65、anks might not be the most space-efficient option.The LNG fuel containment system selected will influence the installed equipment for BOG management and also have an operational impact on tank filling levels and how bunkering(tank pressure and vapor return)is managed in service.The complexity of LNG

66、 bunker vessels is greater than conventional fuel oil bunker vessels and introduces specific compatibility challenges.LNG“Type C”Storage TankFuel Gas Supply System(FGSS)ME-GI or Equivalent EngineFuel Valve Train(GVU)Double-Walled PipesSingle-Walled PipesFuel Preparation Room DF LNG VESSELDUAL-FUEL S

67、OLUTIONS FOR NEWBUILD VESSELS 7The IGF Code permits a number of ways to manage BOG,including consumption,reliquefication,cooling and pressure accumulation.The IGF Code sets criteria for monitoring and managing tank pressure and temperature at all times and for maintaining tank pressure below the rel

68、ief valve setting for 15 days when the vessel is idle with domestic load only.The 15-day criteria may be difficult for atmospheric tanks to achieve on domestic(hotel)load only.Therefore,they may necessitate the fitting of additional BOG management equipment,such as reliquefication systems or gas com

69、bustion units.Large deep-sea vessels would likely specify membrane fuel containment systems or Type B tanks to limit the loss of cargo space compared to conventional fueled ships.However,for large containerships,Type C tanks have shown to be the cheapest,even considering the loss of containers.Slosh

70、ing can be an issue that requires special consideration for membrane tanks.Liquefied natural gas membrane tanks for GFS need to be designed to accommodate all LNG liquid levels as in service.Therefore,the tanks will be designed with higher density insulation materials and membrane reinforcement in c

71、ritical areas.FUEL GAS SUPPLY SYSTEMSThe purpose of the FGSS is to deliver fuel to the engine or consumer at the required temperature and pressure.For gaseous fuels using cryogenic/pressurized liquefied storage,the fuel may be pumped or pressure fed directly in liquid forms,such as LNG,from the tank

72、 and vaporized to a gaseous state for the consumer or supplied in combination with the use of compressed gas from the natural tank BOG.For GFS,the amount of BOG available in certain instances might not be sufficient to sustain the ships power demands at maximum continuous rating(MCR),so the FGSS mus

73、t force the vaporization of LNG into conditions suitable for the engines.In some cases,the designers may prefer to force the LNG to vaporize and send it to the main engines because it could be cheaper and more efficient to boost pressure on LNG and vaporize it on a high-pressure vaporizer rather tha

74、n use a compressor.However,the ship will always still need to manage the BOG and LNG tank pressures,including times when there is no gas consumption by propulsion-related consumers,which can lead to many potential combinations for fuel supply and BOG management equipment.ENGINESFor DF engines,typica

75、lly there is no requirement for FGSS redundancy since the basic safety concept is that the primary fuel remains the fuel oil and seamless transition back to oil mode is required in the event of a safety system trip of the gas fuel system.In those cases where gas is the means of Tier III nitrogen oxi

76、de(NOx)compliance,the International Convention for the Prevention of Pollution from Ships(MARPOL)Annex VI/NOx Technical Code(NTC)permits transit to the next port in Tier II mode.However,for practical reasons,duplication of rotating and reciprocating FGSS equipment,such as submerged LNG pumps or high

77、-pressure cryogenic pumps,is often specified by shipowners and operators for redundancy,reliability and maintenance purposes.DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 8Two common engine and FGSS options are:1.High-pressure DF engine operating on Diesel Cycle where the gas is supplied to this engine a

78、t high pressure (300 bar).Therefore,the FGSS involves high-pressure pumps,evaporators and high-pressure compressors.2.Low-pressure DF engine operating on Otto(gas mode)and Diesel Cycle(fuel mode)where the gas is supplied to the engine at low pressure(6 to 13 bar).Therefore,the FGSS involves low-pres

79、sure pumps,evaporators and low-pressure compressors.Common issues reported so far involve the main engines and the relevant FGSS.However,this is to be expected as these technologies are relatively new to the marine industry.The problems reported on high-and low-pressure engines primarily involve com

80、ponents related to gas mode operation.Based on the collected service experience,engine designers have improved their designs to minimize operational issues.Problems were initially reported with FGSS operation.However,the suppliers of this equipment have also developed and further improved the design

81、s to eliminate operational issues.The crews level of experience is very important.Containing natural gas in the system is still a big issue for less experienced crews.A small gas leak will result in a gas stop and a return to fuel oil operation.Normally,there are no built-in redundancies in the gas

82、system,so maintaining the system and avoiding gas leaks to keep a high uptime on gas fuel use requires skilled engineers.Overall,the development process of DF engines and FGSS is still ongoing.Four-stroke auxiliary LNG DF generators are also available on the market,enabling a vessel to be fully LNG

83、fueled.BUNKERINGSuppose the trading route is known during the design stage,and the potential bunker supplier along the path is identified.In that case,measures/contracts can be established so that the parameters of the LNG vessel during bunkering and the supplier/bunker vessel are aligned and the bu

84、nkering procedures standardized.If trading routes and suppliers are unknown during the design stage,then it might be beneficial to increase the equipment limits on the ship so that issues arising from bunkering are handled correctly.Vapor return needs to be considered during the design when the bunk

85、er supplier can receive and handle vapor return.Vapor return assists with reducing heat transfer while loading the LNG tank with liquid from the bottom in lieu of using top spray to manage pressure accumulation.Additionally,vapor return assists with reducing the duration of the bunker evolution sinc

86、e liquid can be filled in the bottom of the tank,and any vapor pressure accumulated during loading can be returned to the supplier.The temperature of bunkers and pressure control are two issues of concern.The colder the LNG is from the LNG supplier,the better it is for the GFS.This means there is mo

87、re time to manage pressure control in the tanks.If the bunker vessel supplies warm LNG,this might result in handling increased boil-off/pressure,which may lead to an increase in fuel consumption just to handle the pressure.Linked to temperature,an additional concern is understanding if the LNG gas c

88、arriers/bunker vessels vapor return system has been evaluated for conducting vapor balancing in a compatibility study/assessment with the gas-fueled vessel.Vapor balancing design compatibility between supplier and receiver must be verified.As we look at larger bunker tanks,an owner needs to consider

89、 what happens during the cooldown of the bunker tank prior to full rate loading and how to handle the associated flash gas that will be generated.If this is not considered,it will impact the duration of the bunkering operation evolution,which in turn may impact the expected operating profile.In addi

90、tion to verifying the vapor balancing design compatibility between supplier and receiver,there could be challenges with documenting custody transfers.In addition to measuring quantities of LNG supplied to the GFS,the amount of vapor returned may need to be measured.Credits for gas vapor return need

91、to be included in the overall price during custody transfer.Other areas,such as bunker station location and bunker vessel compatibility,are to be considered.Issues may arise if the location of the bunker station is such that the hazardous area from the bunker vessel overlaps areas where the crew(or

92、passengers)are located.SAFETY CONSIDERATIONSTwo machinery space concepts are included in the IGF Code(i.e.,non-hazardous and emergency shutdown(ESD)machinery space).The ESD machinery space concept introduces additional measures to provide an equivalent level of safety to the conventional non-hazardo

93、us machinery space.The application of the ESD machinery space has been limited so far because of the growing availability of engines that can be supplied to meet the double barrier DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 9criteria and perhaps because of the additional vessel complexity and cost tha

94、t meeting the ESD machinery space concept brings.The non-hazardous machinery space concept is based on the use of double barriers for all gas-containing components such that a failure in a single barrier cannot lead to a fuel gas release into the space.The main differences between the two machinery

95、space concepts are shown in the Figures 2 and 3.The non-hazardous machinery space also shows the GVU room.This may be a separate space outside of the machinery space,or a GVU unit,which is a self-contained unit that is essentially an extension of the double barrier piping system and may be located w

96、ithin the non-hazardous machinery space.Figure 2:IGF non-hazardous machinery space concept.Figure 3:IGF ESD machinery space concept.Ventilation Outlet 30 A/CZone 0VentilationDuct Ventilation Inlet from Non-hazardous Area in Open AirFVT RoomMaster Fuel ValveNon-hazardous Machinery SpaceReturnReturnFu

97、elDouble Wall Fuel Pipes*Double wall fuel pipes may be sealed inert gas or pressurized typeGas Detector 1Gas Detector 2*Leak DetectorDFDEngineZone 1Zone 1*Or Single Self-monitoring DetectorDUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 10Vessels must also find practical locations that meet the prescriptiv

98、e requirements for the fuel preparation room,vent mast and the nitrogen-generating equipment,as per the ABS Guide for LNG Fuel Ready Vessels.The LNG fuel containment system vent mast location can be challenging because of the requirements on hazardous area zones around the vent mast exit and the phy

99、sical location criteria for the LNG tank pressure relief valve vents.These need to be at least 10 meters(m)from any air intake,air outlet or opening to accommodation,service and control spaces or other non-hazardous areas and any exhaust system outlet.Vent heights shall normally not be less than B/3

100、 or 6 m.The ABS Guidance Notes on Gas Dispersion Studies of Gas Fueled Vessels may be referenced for additional guidance on gas dispersion studies associated with alternative vent termination locations and proposed hazardous areas.Hazardous areas are challenging due to the location of tanks,fuel gas

101、 piping systems,FGSS and gas consumers.Based on the sections above,the following points summarize the main high-level issues to consider in the initial specification discussions for DF LNG vessels:Ensure that non-hazardous machinery space is selected.The ESD machinery space concept introduces additi

102、onal measures to provide an equivalent level of safety to the conventional non-hazardous machinery space adding vessel complexity and cost.Refer to the ABS Guidance Notes on Gas Dispersion Studies of Gas Fueled Vessels for additional guidance associated with alternative vent termination locations an

103、d proposed hazardous areas.As per most gas-fueled ships in operation,it is recommended to select IMO Type C pressurized fuel tanks because these are relatively inexpensive to manufacture and simple compared to the other fuel containment types,particularly in the smaller sizes required by the current

104、 gas-fueled fleet.If a membrane tank is used,other considerations will need to be addressed compared to pressurized tanks due to the major differences in complexity during new construction.Namely,the choice of material for the surrounding hull(ballast,cofferdam),a more complex BOG management system,

105、which could include subcooling,an upscaling of the nitrogen gas generating system and a reinforcement of the membrane and insulation as mid-filing sloshing effect will be bigger than for conventional LNG carriers using the same containment.The tanks natural boil-off rate(BOR)will be provided,and BOG

106、 management protocols will be presented,including the IGF Code 15-day holding time criteria.Despite no requirement for FGSS redundancy for DF engines,for practical reasons,duplication of rotating and reciprocating FGSS equipment,such as submerged LNG pumps or high-pressure cryogenic pumps,is recomme

107、nded for redundancy,reliability and maintenance purposes.Bunkering must be considered at the beginning of a design project for optimum design results.If during the design stage the trading route is known and the potential bunker supplier along the route is identified,measures/contracts can be establ

108、ished so that the parameters of the LNG vessel during bunkering and the supplier/bunker vessel are aligned and procedures of bunkering standardized.If trading routes and suppliers are unknown,then it might be beneficial to increase the equipment limits on the ship so that issues arising from bunkeri

109、ng are handled correctly.KEY DESIGN REQUIREMENTS1234567DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 11Methanols uptake and application as a marine fuel is only beginning,as it was approved for inclusion in the IMOs Interim Guidelines for Low-Flashpoint Fuels in November 2020.Methanol may be used on boar

110、d ships as fuel for internal combustion engines or as a fuel source for fuel cell operation.Methanol is a widely shipped commodity and used in a variety of applications,such as the chemical industry,for many decades.The supply chains exist and are well-positioned to reliably supply methanol as a mar

111、ine fuel in many ports worldwide.As methanol is a liquid at ambient temperature,the existing liquid fuel infrastructure may also be leveraged to supply methanol with limited conversion.Existing conventional bunker vessels may also be a viable option for maritime bunkering once suitably modified.Figu

112、re 4:Installations on board new-build methanol ship.The on board containment of methanol is easier than LNG.As a liquid fuel,only minor modifications are needed to existing systems/infrastructure used for conventional marine fuels.The modifications are mainly due to the high flammability and the low

113、-flashpoint characteristics of methanol.Major safety considerations include:Methanol tank location Methanol protection Inerting and venting of a methanol tank Spill containment Vapor and fire detection FirefightingMethanol distribution infrastructure and the availability of engines are catching up t

114、o natural gas.Still,the real-world experience of large commercial marine ships demonstrates that methanol is a serious contender for a long-term future marine fuel.Ship operators running methanol fleets would be able to procure methanol with relative ease.Methanol is available at more than 120 ports

115、 worldwide and shipped globally.Today,there are more than 90 methanol production facilities all over the world,with an annual supply of nearly 100 million metric tons(Mt)(Methanol Institute,2023).DF METHANOL VESSELCH3OHFuel Valve Train(GVU)MethanolService TankMethanolSupply SystemME-LGI EngineMethan

116、ol Cargo Fuel PumpDouble-Walled PipesSingle-Walled PipesDUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 12Machinery SpaceAccommodationMethanolMethanolCategoryAMachinerySpaceTanks surrounded bycoferdams except surfaces bound by shell plating below the lowest possible waterline,other methyl/ethyl tanks or fu

117、el preparation spacesCoferdams arranged for purging or filling with water through non-permanent connection600mm coferdams and A-60 separation to Category A machinery spacesFuel tanks inerted at all timesControlled tank venting systemP/V valvesVent mast 6m+4m hazardous zonesGreen methanol production

118、projects have been announced across the world.In the short term,green methanol will be produced mainly from biomass;it is therefore expected to be produced first from Asia and South America.In China,there are more than 10 projects that have been announced in the first half of 2024(at least three of

119、which are expected to begin delivering from 2025 to 2026),with production capacity ranging from 150,000 to 1 million tonne per annum(mtpa).Europes largest green methanol plant,which has an estimated annual production capacity of 300,000 tonnes,will begin operating in 2028.After 2027,we will see a su

120、bstantial amount of green methanol supplied from China and other regions.According to the International Renewable Energy Agency(IRENA),by 2050 e-methanol and biomethanol green methanol are expected to make up nearly 80 percent of total production,which could reach 500 mtpa.Whether produced from gray

121、,blue or green feedstocks,the methanol molecule will have the same physical properties,facilitating the transition of marine methanol over time as more low-carbon and net carbon-neutral methanol enters the global supply chain.FUEL CONTAINMENTIn addition to achieving a lower carbon footprint,the liqu

122、id state of methanol makes it easy to store and readily available for bunkering.For onboard storage,low-flashpoint fuels that are liquid at ambient conditions,such as methanol or ethanol,can be stored in conventional fuel tanks with a controlled tank venting system and thus can be simpler to apply c

123、ompared to liquefied gaseous fuels.Methanol is often proposed for locations below the waterline.This can promote the use of several ballast tanks as potential fuel tanks.However,these tanks need special coatings(zinc,etc.),and due to the low flashpoint,they may require a nitrogen blanket for the tan

124、k vapor space.Regardless of the fuel or technology selected,the decision process is very vessel-specific and additional cofferdams or hold spaces,as well as A-60 fire insulation,may also be required.Figure 5:Methanol tank location.FUEL SUPPLY SYSTEMTwo different FSS are required,depending on the typ

125、e of methanol-burning engine.One type of FSS required involves relatively low fuel supply pressure,with all high-pressure pumping is done within the injector.The engines methanol FSS is significantly simpler compared to LNG without the need for cryogenic storage and handling.The fuel supply to the e

126、ngine can be accomplished using a low-pressure system,e.g.,10 bar.The other type of FSS requires a high-pressure(600 bar)fuel pump room as well as the installation of the double-wall fuel piping system with associated safety systems.For both low-and high-pressure systems,the similarity to LNG is the

127、 safety considerations due to the high flammability characteristics of the methanol fuel and its low flashpoint.DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 13ENGINESAll methanol-powered marine engines so far are DF engines,capable of running on both methanol and traditional marine fuels,such as heavy f

128、uel oil(HFO)or marine diesel oil(MDO).This allows the vessel to use methanol when available and switch to conventional fuels when necessary,ensuring operational flexibility.These engines are designed to optimize combustion for both fuels,using specialized injectors,compression settings and combustio

129、n strategies.Most of the engine designers of methanol-burning engines have adopted the high-pressure diesel combustion process for utilizing methanol.Fuel injection is accomplished by either a booster fuel injection valve that raises the injection pressure up to 550 to 600 bar,or by a common rail in

130、jection system.The first application of this concept was in methanol-burning DF engines on several methanol carriers.For the DF combustion concept,i.e.,the diesel process in oil and low-flashpoint fuel modes,the MCR and transient response performance is equivalent to the conventional oil-fueled engi

131、ne range and operates with no fuel slip.This prevents the development of any formaldehydes in the exhaust gas.Formaldehyde can cause cancer,and it is classified as a carcinogen by several health organizations,including the Environmental Protection Agency(EPA)and the International Agency for Research

132、 on Cancer(IARC).The DF methanol engines can run on liquid methanol and fuel oils as pilot fuels(low sulfur MDO/HFO or biofuels)depending on the operator preference,fuel availability,air pollution consideration and relative fuel cost.Both two-stroke and four-stroke methanol-fueled engines are availa

133、ble.Cylinders are placed in-line or in a V-shape depending on the total power output of the engine.BUNKERINGFuel supply,infrastructure and bunkering of methanol remain as challenges for its widespread adoption.While developing bunkering infrastructure for methanol,lessons can be learned and adapted

134、from the use of LNG as marine fuel.Bunkering facilities,onboard containment systems,FSS and marine engines are the key aspects that need to be assessed for the use of methanol as a marine fuel.The bunkering station must have adequate ventilation and preferably located on the open deck.For semi-enclo

135、sed or closed bunkering stations,effective mechanical ventilation must be provided and may also require a risk assessment.As a liquid fuel in ambient conditions,bunkering equipment and practices for methanol are much closer to that for conventional fuel oil bunkering.Historical expertise and best pr

136、actices have been developed through the chemical tanker sector and ships subject to the International Code for the Construction and Equipment of Ships Carrying Dangerous Chemical in Bulk(IBC Code),but also through the offshore sector with the experience gained through handling methanol for drilling

137、operations.For example,the United States Coast Guard(USCG)CG-ENG policy letter 03-12 provides USCG policy for implementation of IMO Resolution A.673(16)for the handling of hazardous and noxious liquid substances in bulk on offshore support vessels(OSVs),with specific requirements for handling methan

138、ol.The IMO has adopted Resolution A.1122(30),the Code for the Transport and Handling of Hazardous and Noxious Liquid Substances in Bulk on Offshore Support Vessels(OSV Chemical Code),which now supersedes the IMO Resolution A.673(16).SAFETY CONSIDERATIONSFIRE PREVENTION AND DETECTIONThe Interim Guide

139、lines for the Safety of Ships using Methyl/Ethyl Alcohol as fuel(Maritime Safety Committee(MSC).1/Circ.1621)and the Methanol Institute Safe Handling Guide give provisions for methanol fire detection and firefighting techniques.Methanol as a liquid does not vaporize rapidly at ambient temperature and

140、 pressure as a liquefied gas would.However,methanol vapor in concentrations between 6 to 36 percent of air is flammable when introduced to an ignition source.DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 14Any methanol manifold,ventilation or pressure/vacuum(P/V)relief valve requires an appropriate clear

141、 adjacent area to avoid the introduction of ignition sources or sparks.The autoignition temperature of methanol gas is 450 C,which requires electrical equipment to be assigned a T2 surface temperature class.Inert gas can protect methanol tank vapor space from explosive behavior.In addition to the ri

142、sk of explosion,CO2 in the presence of methanol and moist or salty conditions can create corrosive conditions.Therefore,inert gases containing CO2 should be avoided,and nitrogen gas is to be used to blanket methanol.Methanol is known for burning with a low-light and low-temperature flame,and therefo

143、re,flame detection if burning pure can be especially difficult.To protect against methanol fires,flame detection equipment such as infrared(IR)cameras,foam extinguishing systems and robust operational procedures must be in place.Methanol flames do not produce smoke or soot,so a smoke detector will n

144、ot likely be an effective source of fire detection.Heat detector-type fire detection systems may also be unreliable for methanol due to the flames low temperature.Flame detectors with IR light detection are ideal for detecting methanol flames.Soot particles in typical fire smoke tend to absorb elect

145、romagnetic radiation from CO2.However,as there is no soot from methanol flames,CO2 radiation is more significant,and the flame is easily detected in the IR light region.Some flame detectors only alarm when light from both the ultraviolet(UV)and IR regions are detected,but these are not to be used fo

146、r methanol flame detection.Vapor detection can also be used simultaneously for leak and fire detection by monitoring oxygen and CO2 levels.Closed-circuit television(CCTV)can also help with fire detection,and IR cameras used in conjunction with CCTV could be used for methanol flame detection,but thes

147、e may incur added expenses beyond what is minimally necessary.Protection against leaks adjacent to methanol tanks or pipes must include gas detection systems near expected leak points,as well as positions near the ceiling and in surrounding low points.Alarms for gas detection should be sensitive eno

148、ugh to alarm well before the concentration levels reach toxic or flammable levels.Tank overflow and leak protection must be adequate for the holding arrangement in place to prevent flammable conditions in areas with potential ignition sources.In some cases,additional safety measures for cofferdams s

149、hould be in place to prevent a potentially dangerous buildup of methanol liquid or vapor.CORROSIONMethanol is corrosive to certain materials,and using methanol as a marine fuel may require the redesigning of some combustion engine parts.Corrosion-inhibiting additives or special coatings could also b

150、e an option to reduce methanol corrosion.The conductivity of methanol increases its corrosiveness in the presence of certain metallic materials such as aluminum and titanium alloys.These materials are commonly used in natural gas and distillate fuel systems but may not be used for pipes or fittings

151、intended for methanol fuel or methanol fuel blends.Storage tanks holding methanol are to have an appropriate grade of stainless steel or methanol-resistant coating to the tank interior.If coatings are used,it is important to consider that any acidic impurities can damage the coating material,and the

152、se damages are to be addressed quickly before accelerated corrosion occurs,including pitting,iron pick-up and further methanol contamination.Non-metallic materials used in fuel tanks and pipes are to consist of appropriate methanol-compatible materials,such as nylon,neoprene or non-butyl rubber.TOXI

153、CITYWhen carried as cargo,the IBC Code classifies methanol as a toxic substance.In addition,most Safety Data Sheets also categorize liquid methanol as a toxic chemical.The handling of methanol is to be carried out carefully as it contrasts with conventional marine fuels by its toxicity and danger to

154、 humans.Crews are to be properly trained and be aware of the additional hazards and characteristics of methanol,including in the case of leaks,spills or exposure.The Interim Guidelines for the Safety of Ships using Methyl/Ethyl Alcohol as Fuel(MSC.1/Circ.1621)provide guidelines for crew safety.DUAL-

155、FUEL SOLUTIONS FOR NEWBUILD VESSELS 15CARBON DIOXIDE FIRE EXTINGUISHING SYSTEMWhen comparing CO fire extinguishing system capacity for methanol fires with conventional fuel oil fires,its important to understand the differences in fire behavior,fuel characteristics and the amount of CO required to su

156、ppress each fire type.Both diesel oil and methanol present unique challenges,but the general principles of extinguishing are similar CO works by displacing oxygen and reducing the temperature to extinguish the fire.Requirements refer to a free CO2 gas volume equal to at least 40 percent of the volum

157、e of the space protected for conventional fuel oil fires.However,based on the characteristics of a methanol fire,as well as considering the research and theoretical studies conducted in the industry,the minimum extinguishing concentrations for methanol fires compared to conventional fuel fires shoul

158、d be increased by about 25 percent to assure an equivalent effect.Considering the above,the International Association of Classification Societies(IACS)published the Unified Interpretation(UI)GF21 requiring that where CO2 fire-extinguishing systems are used as fixed gas fire-extinguishing systems for

159、 machinery space or fuel preparation space in methanol-fueled vessels,the quantity of CO2 carried is to be sufficient to give a minimum volume of free gas equal to 50 percent of the gross volume of the largest space protected,including the machinery space casing.This UI is to be uniformly implemente

160、d by IACS societies on ships contracted for construction on or after 1 January 2026,to which the Administration has required the application of MSC.1/Circ.1621KEY DESIGN REQUIREMENTS Based on the sections above,the following points summarize the main high-level issues to consider in the initial spec

161、ification discussions for DF methanol vessels:Inert gas protects the methanol tank vapor space from explosive behavior.Inert gases that contain CO2 are to be avoided,and nitrogen gas is to be used to blanket methanol.In addition to the risk of explosion,CO2 in the presence of methanol and moist or s

162、alty conditions can create corrosive conditions.Flame detection equipment such as IR cameras,foam extinguishing systems and robust operational procedures are to be in place to protect against methanol fires.Methanol flames do not produce smoke or soot,so a smoke detector will not likely be an effect

163、ive source of fire detection.Heat detector-type fire detection systems may also be unreliable for methanol due to the flames low temperature The handling of methanol is to be carried out carefully as it contrasts with conventional marine fuels by its toxicity and danger to humans.Crews are to be pro

164、perly trained and be aware of the additional hazards and characteristics of methanol,including in the case of leaks,spills or exposure.The Interim Guidelines for the Safety of Ships using Methyl/Ethyl Alcohol as Fuel(MSC.1/Circ.1621)provide guidelines for crew safety.Methanol is corrosive in the pre

165、sence of aluminum and titanium alloys,which are commonly used in fuel systems for natural gas and distillate fuels.To solve this problem,it is possible to apply corrosion inhibiting additives or coatings,provided they are not likely to be damaged by acidic impurities.Alternatively,or additionally,no

166、n-metallic materials such as nylon,neoprene or non-butyl rubber can be used in fuel tanks and pipes.The bunkering station is to be provided with adequate ventilation and is to be preferably located on the open deck.For semi-enclosed or closed bunkering stations,effective mechanical ventilation is to

167、 be provided and may also require a risk assessment.Methanol is often proposed for locations below the waterline.This can promote the use of a number of ballast tanks as potential fuel tanks.However,these tanks need special coatings(zinc,etc.),and due to the low flashpoint may require a nitrogen bla

168、nket for the tank vapor space.Regardless of the fuel or technology selected,the decision process is very vessel-specific.Additional cofferdams,holding spaces or A-60 fire boundaries may also be required.For DF methanol engines,combustion is initiated with a pilot injection of conventional fuel oil.O

169、peration indicates slightly improved efficiency over the diesel variant,expected sulfur oxides and particulate matter reductions from the clean fuel,and NOx reductions of 40 to 50 percent.The NOx reductions are not large enough to achieve IMO Tier III levels and thus would require exhaust aftertreat

170、ment or blending water with the methanol.If blending water with methanol,a separate NOx compliant aftertreatment system is required to achieve NOx Tier III compliance when in fuel oil mode.DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 16Ammonia as a fuel has additional challenges before being commerciall

171、y available for the non-gas carrier fleet.Ammonia-fueled engines are under development,and ammonia use is also being explored in fuel cells.Ammonia can be a zero-carbon fuel and provide solutions for the decarbonization of the global fleet.Nevertheless,the cost of producing ammonia-based fuels and m

172、aking them safe for marine use is being explored.Apart from the cost of adapting infrastructure,ammonia is toxic to humans and aquatic life.Therefore,considerable safety measures must be taken.Figure 6:Installations on board new-build ammonia tanker.When used as fuel in internal combustion engines,a

173、mmonia combustion predominantly produces water and nitrogen.Unburnt ammonia must be closely controlled.Guidance on acceptable limits to avoid plume formation or human health hazards can be drawn from other regulatory requirements,where limits of 2 to 10 ppm may be applied.The IMO NOx limits would al

174、so be applicable upon the combustion of ammonia.Fuel containment,distribution and supply systems can be based on existing technologies and prescriptive requirements.In a liquid state,ammonia is not flammable and cannot ignite.However,it vaporizes rapidly,and the vapor has a narrow flammable range.Th

175、e main concern is toxicity,and additional measures are needed to control normal and abnormal discharges.Understanding the requirements of ammonia gas,including low-temperature service,pressurized storage tanks,flammable gases and working with corrosive and toxic materials,is key to addressing the sa

176、fety hazards of using ammonia as a marine fuel.Some of the considerations when using ammonia as fuel on a vessel are:Corrosion Design Equipment failure Cascading failures Safety management plan Personnel training to reduce human errorDF AMMONIA VESSELNH3Ammonia Supply SystemAmmonia“Type C”Service Ta

177、nkME-LGIA or Equivalent EngineAmmonia Cargo Fuel PumpCargo Machinery Room including Reliq SystemDouble-Walled PipesSingle-Walled PipesFuel Valve Train(GVU/FVT)DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 17Ammonia is currently produced in large quantities as an input for products in the fertilizer and c

178、hemical industries.No shipping contracts have been signed but supply agreements have been negotiated between suppliers and energy majors such as Jera(Blue Ammonia from the U.S.to Japan).Existing LNG producers and oil majors are already expanding their blue ammonia plants to meet the forecasted deman

179、d.To realize the large-scale production of green ammonia for maritime shipping,its production capacity,along with that of renewable electricity and green hydrogen,will need to grow tremendously.Current projections for the growth in global production appear to indicate there will be enough renewable

180、electricity to produce the volumes of green ammonia needed for the maritime fleet alone by 2040.However,by that time,shipping will also be competing with other industries for renewable electricity and green hydrogen necessary to produce ammonia,as well as with other sectors that also depend on the c

181、onsumption of ammonia,such as agriculture(EMSA,Sept 2023).FUEL CONTAINMENTAmmonia maintains a liquid state at refrigerated(-33 C and 1 bar)or pressurized(20 C and 8.6 bar)conditions.Industrial scale storage uses low temperatures,which requires energy to maintain.This option may have a lower capital

182、cost than pressurization in some cases due to the lower storage design pressures.However,pressurized storage in Type C tanks may be a convenient marine solution even though the IMO Interim Guidelines for the Safety of Ships Using Ammonia as Fuel mandate that the temperature of the liquefied ammonia

183、in the fuel tanks at a temperature of no more than-30 C at all times.Besides,the pressure accumulation options introduced in IGF Code applicable to liquified fuel tanks is not listed as a valid option for ammonia fuel tanks in the Interim Guidelines.As ammonia has low energy content,it will require

184、larger tanks for storage,and their location on board will be a critical design factor.When ammonia is used as a fuel,the changes in vessel arrangement are dependent on the location and type of ammonia tank/containment system.Cargo capacity is also expected to decrease based on the use of ammonia com

185、bustion engines or ammonia fuel cell arrangement employed.The additional space for fuel,due to lower energy density,may require larger vessels sizes,decreased cargo space or more frequent bunkering.Ammonia tanks need to comply with the requirements of the IGC and IGF Codes on minimum distances from

186、the hulls shell,accommodation space,design and safety requirements,etc.However,this is part of the risk assessment route for approval.The IGC Code contains specific material requirements for ammonia fuel containment under Section 17.12,and these are expected to be applied,as applicable,for marine fu

187、el storage tanks.FUEL SUPPLY SYSTEMThe purpose of the FSS is to deliver fuel at the correct temperature and pressure to the engine.Using gaseous fuels introduces complexity to the fuel supply and consumer systems,creating greater interdependence between the key systems over conventional fuel systems

188、.For fuels using low temperature/pressurized liquefied storage,such as ammonia,the fuel can be pumped or pressure fed directly in liquid form.The FSS can be one of the more complex and expensive systems required for gas-fueled applications.The FSS needs to increase fuel supply quantities depending o

189、n the engine fuel demand.This transient fuel demand can be a challenge,particularly when maintaining fuel supply readiness in times of high demand or zero demand,without causing a shutdown of the FSS.It may also not be part of the engines original equipment manufacturer(OEM)supply but solely designe

190、d to comply with the engines OEM specifications.Systems for ammonia as a fuel are similar to what is specified for liquefied petroleum gas(LPG),though they are designed for a slightly higher pressure and 2.4-time larger flow.In addition,a system to collect and avoid the release of ammonia vapor must

191、 be included.Liquid fuel systems can be simpler than gas systems.However,this depends on the properties of the fuel being used and the prime mover technology.ENGINES Methanol is widely recognized as an effective intermediate solution for reducing GHG emissions,whereas ammonia is considered a long-te

192、rm solution.Consequently,the development of ammonia engines is not yet at the same level as that of methanol engines.ABS is witnessing the beginning of ammonia engines for maritime applications,with a few projects selected and approximately 50 ships firm orders(Feb.2025).More testing is underway,wit

193、h adjustments on pilot fuel and additional ammonia slip and nitrous oxide(N2O)mitigation measures.DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 18Burning ammonia in an internal combustion engine uses either the Diesel or Otto Cycle principle.Each combustion cycle comes with its advantages and challenges

194、with respect to engine and FSS design,engine performance and emissions.In general,the low-pressure concept is for engines adopting the Otto Cycle and high-pressure for those using the Diesel Cycle.Ammonia has a high auto-ignition temperature,a high heat of vaporization and a narrow flammability rang

195、e.Due to these characteristics,ammonia typically requires a pilot fuel injection.High-pressure injection systems can help minimize ammonia slip;an important consideration given its toxicity.Slow flame velocity,ignition temperature,narrow flammability range and lower heat of combustion are issues for

196、 ammonia ignition.Engine control strategies by engine manufacturers can address these issues.The advent of electronic engine controls and existing DF technologies,including the diesel process,shows promise in addressing these issues.Ammonia has a high heat of vaporization(1,371 kJ/kg),which results

197、in considerable evaporative cooling of the mixture after injection and reduces the cylinder temperature at the start of combustion,helping to control NOx formation.19DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELSIn the Diesel Cycle,the ammonia is injected into the combustion chamber at a high pressure in

198、liquid form.The engines behavior is the same as when it operates on diesel fuel.Therefore,it is expected that the ammonia is being burned with very limited ammonia slip and the amount of ammonia in the cylinder lubrication oil is negligible.Since most of the ammonia fuel is burned,limited amounts wi

199、ll land on the liner and piston.Therefore,it will likely have a very limited impact on liner wear and on combustion chamber components in the engines.However,the biggest impact is expected to be on the injectors.In the Otto Cycle,the ammonia is mixed with air prior to combustion resulting in a highe

200、r amount of ammonia slip,N2O and NOx.Exhaust gases must be treated accordingly with aftertreatment systems to reduce ammonia releases to the atmosphere.Unburnt ammonia will be present in the combustion chamber,so the combustion chamber component will be exposed to ammonia.Therefore,corrosion of the

201、engine component can potentially be an issue,but it is unknown how big the impact will be on the wear and tear of the engine component.Ammonia combustion and slip emissions mitigation can be achieved by:Selective catalytic reduction(SCR)Exhaust gas recirculation,however this solution is not currentl

202、y offered Engine design optimization and tuningThe choice of aftertreatment technology can vary depending on the engine type(two-or four-stroke)and combustion cycle(Diesel Otto Cycle).Diesel Cycle Engines:Initial results suggest that these engines may achieve Tier III NOx emission levels through eng

203、ine tuning alone,potentially eliminating the need for SCR.Ammonia slip is also expected to be low as initial indications from engine makers show potential for meeting the 30 ppm target without additional treatment.Otto Cycle Engines:Initial testing indicates higher NOx and ammonia slip in the exhaus

204、t compared to Diesel Cycle engines.This might necessitate a larger SCR catalyst to remove NOx and additional ammonia injection to achieve Tier III compliance.Moreover,higher NO emissions might require an additional NO reduction catalyst integrated into the SCR system.FUEL CELLSThe use of ammonia in

205、fuel cells is still relatively experimental.However,the current pace of development is accelerating,with large stationary plants currently under development.To use ammonia in fuel cells,the hydrogen contained in the molecule must be separated.Although it is possible to achieve this through an extern

206、al reformer so that the hydrogen can be used in low-temperature fuel cells such as a polymer electrolyte membrane(PEM),using ammonia directly in high-temperature fuel cells such as a solid oxide fuel cell(SOFC)can be a more efficient solution.There are also other advantages of using ammonia in SOFC,

207、such as high electrical efficiency,the absence of NOx production and the lack of vibration.Fuel cell development is not as mature as internal combustion engines and typically has a higher cost.These factors are expected to show gradual improvement as research continues.An additional shortcoming of S

208、OFC compared to PEM is the sensitivity of the solid oxide ceramic materials used to heat gradients,which require relatively long and careful start-up and shut-down procedures and often last for hours.Ideally,SOFC plants should run continuously to minimize the risk of permanent damage.This would typi

209、cally require the use of batteries for energy storage to accommodate fluctuations in the load demand.BUNKERINGBunkering is an indispensable operation of supplying fuel to a ship for use by the ships machinery.Conventionally,any fuel/oil used for this purpose is called bunker fuel or bunker oil.Curre

210、ntly,in the marine industry,ammonia is a bulk commodity frequently loaded/unloaded from gas terminals to ships and ships to gas terminals.The operation is similar to bunkering.The difference is that ammonia is transferred to a dedicated fuel storage tank instead of a cargo tank.As a new bunker fuel,

211、ammonia will necessitate a complete establishment of provisions and guidelines for a successful start-up.Previous experience from the fertilizer and chemical industry,and the recent development from LPG/LNG bunkering will help inform the process.It is necessary to find gaps between established indus

212、try and marine bunkering context and solutions to align operations using technical and operational measures.Ammonia can be stored in liquid form pressurized,semi-refrigerated or fully-refrigerated depending on the needed volume for safe storage,varying from small pressurized 1,000-gallon nurse tanks

213、 up to liquefied 30,000 metric ton storage tanks at distribution terminals.20DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELSDuring transfer from one tank to another,either cold inbound or warm inbound is chosen as a result of the transferred volume and re-refrigeration process.The capacity of an onshore fu

214、ll-pressure non-refrigerated tank is usually limited,and the handling can be energy-intensive.Lessons learned have identified high-risk areas such as leakage when handling and toxicity.Measures need to be taken to avoid leakage,handle toxicity and maintain equipment in good working condition through

215、 regular inspection.The use of anhydrous ammonia in fertilizers,SCR reagents and refrigerants has provided enormous knowledge and experience in handling and transporting ammonia.This extensive established chemical/process industry infrastructure can be leveraged and extended to marine terminals and

216、ports.Due to the similar physical properties,operational experiences on LPG bunkering will provide additional useful guidance in creating ammonia bunkering procedures.Three modes of future ammonia bunkering via truck,tank or ship are envisaged.However,being chemically far from LPG,the safety aspect

217、of ammonia will deserve a separate study that may benefit from the established chemical industry,where safety precautions,material compatibility and machinery are meticulously addressed.SAFETY CONSIDERATIONS For ammonia fueled vessels,the specific vessel arrangements will vary depending on the actua

218、l fuel pressure and temperature settings of the fuel.The prime mover selected and fuel storage conditions will also affect the vessel design.The links between fuel storage,fuel preparation and fuel consumer are much more interdependent than with conventional fuels.It is critical that equipment and s

219、ystem design decisions consider this interdependence.For ammonia-fueled ships,the main systems that require different or additional concepts in ship designs are the ammonia fuel containment system,associated ammonia bunker station and transfer piping,an FSS,an ammonia release and mitigation system,B

220、OG handling,reliquefication,fuel valve unit/train,nitrogen generating plant,vent piping systems and masts,and for some ammonia tank types,additional equipment for managing tank temperatures and pressure.Water spray,water screen and deluge systems,specific personal protective equipment,independent ve

221、ntilation for ammonia spaces,emergency extraction ventilation and closed fuel systems may also be required.21DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELSKEY DESIGN REQUIREMENTSBased on the sections above,the following points summarize the main high-level issues to be considered in the initial specificat

222、ion discussions for DF methanol vessels.As the links between fuel storage,fuel preparation and fuel consumer are much more interdependent than with conventional fuels,it is critical that equipment and system design decisions consider this interdependence.Refer to the ABS Rules for Building and Class

223、ing Marine Vessels(MVR)5C-18-6/3.3.3 for initial guidance when conceptualizing the design of mechanical ventilation of the spaces where ammonia is used and stored.Guidance is provided on the independence of the ventilation system,manning,air changes,stopping of ventilation fans,closing the ventilati

224、on openings,air inlet positioning,exhaust duct positioning,etc.Special attention must be paid to the location of the vent mast.For ammonia tanks,risk assessment should consider the requirements of the IGC and IGF Codes on the minimum distances from the hulls shell,accommodation space,design and safe

225、ty requirements,etc.The IGC Code contains specific material requirements for ammonia fuel containment under Section 17.12,and these would be expected to be applied,as applicable,for marine fuel storage tanks.Special attention is required to the engine type selected,due to the pros and cons of each t

226、ype.For Diesel Cycle,the engines behavior is the same as when it operates on diesel fuel with very limited ammonia slip and the potential to achieve Tier III NOx emission levels through engine tuning alone.For Otto Cycle,the ammonia is mixed with air prior for combustion resulting in higher amounts

227、of ammonia slip,N2O and NOx.Exhaust gases will have to be treated accordingly with aftertreatment systems to reduce ammonia releases to the atmosphere.When bunkering ammonia,measures need to be taken to avoid leakage,handle toxicity and maintain equipment in good working condition through regular in

228、spection.Bunkering procedures may use operational experiences from LPG bunkering due to similar physical properties.The safety aspect of ammonia will deserve a separate study that may benefit from the established chemical industry,where safety precautions,material compatibility and machinery are met

229、iculously addressed.12345VENTING AND DISPERSIONContinuous mechanical ventilation of the spaces where ammonia is used and stored is required.The ABS Requirements for Ammonia Fueled Vessels and IMO Interim Guidelines for the Safety of Ships Using Ammonia as Fuel are to be used for guidance when concep

230、tualizing the design.ABS Rules provide guidance on the independence of the ventilation system,manning,air changes,stopping of ventilation fans,closing the ventilation openings,air inlet positioning,exhaust duct positioning,etc.Increased or emergency mechanical ventilation systems,that should be acti

231、vated automatically in the case of ammonia leakage detection,are also required in those spaces.The ABS Requirements for Ammonia Fueled Vessels and IMO Interim Guidelines for the Safety of Ships Using Ammonia as Fuel are also to be used for the limits of the toxic areas around the ventilation inlets/

232、outlets and other openings of the spaces where ammonia is used and vent mast on deck.A gas dispersion analysis should also be carried out in order to determine the extent of the toxic areas to ensure safe distances from the toxic areas to the safe spaces,such as accommodation,service and machinery s

233、paces,control stations,etc.DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 22REGULATORY CONSIDERATIONSHistorically,the International Convention for the Safety of Life at Sea(SOLAS)has prohibited the use of low-flashpoint fuel oils less than 60 C,except for use in emergency generators where the limit is 43

234、C,and subject to several additional requirements detailed under SOLAS II-2 Regulation 4.2.1.In parallel,the IMO adopted the IGF Code,which serves as an international standard for ships operating with gas or low-flashpoint liquids as fuel,other than those ships covered by the IGC Code.The IGF Code is

235、 mandatory by SOLAS II-1 Part G.The adoption of the IGF Code introduced a framework and requirements under SOLAS for burning fuels with a flashpoint less than 60 C.With the adoption of the IGF Code and 2016 IGC Code,the IMO established the regulatory safety requirements and framework for using natur

236、al gas and other low-flashpoint fuels on all ship types.In all cases,the prescriptive and goal-based objectives apply the following three safety principles and general arrangements to mitigate the risks of using low-flashpoint fuels:Prevention of leakage,e.g.,double barriers,sealing systems,protecti

237、ve locations,cofferdams and air locks Prevention of explosive or toxic atmosphere,e.g.,ventilation,gas detection,hazardous area classification,master gas fuel valves,fuel block and bleed valves,inert gas barriers and fuel purge systems Explosion mitigation,e.g.,explosion relief valves,pressure vent

238、systems,design for worst case pressure rise,specialized fire detection and firefighting equipment.Although the IGF Code has been developed for using fuels with low flashpoint,prescriptive requirements are currently applicable to natural gas only.Other low-flashpoint fuels may also be used as marine

239、fuels,provided they meet the intent of the goals and functional requirements of the IGF Code and provide an equivalent level of safety with natural gas.This approval process is by application of the alternative design criteria under 2.3 of the IGF Code and equivalency shall be demonstrated as specif

240、ied in SOLAS II-1/55,which refers to the engineering analyses submitted for approval(by the Administration)to be based on the MSC.1/Circ.1212/Rev.1 guidelines.IGF CODE 23DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELSAlternative fuels have drawn a lot of interest from the marine industry for the potential

241、to become a long-term solution for decarbonization.The IMO has already adopted MSC.1/Circ.1621,the Interim Guidelines for the Safety of Ships using Methyl/Ethyl Alcohol as Fuel.The Sub-Committee on Carriage of Cargoes and Containers(CCC)9 established a work plan,referenced below in Table 2,for the d

242、evelopment of several standards for other alternative fuels through the IGF Code.The scope of the remaining work extends to 2026 and includes the development of standards for low-flashpoint oil fuels,hydrogen,ammonia,fuel cells and methyl/ethyl alcohol fuel standards.It may also extend to the develo

243、pment of a mandatory instrument for the use of fuel cells and methyl/ethyl alcohols.The approval of the guidelines for ships using ammonia as fuel is planned for approximately the end of 2024 during the MSC 109 meeting.MeetingObjectivesYearISWG-AF 1 Further develop/finalize guidelines for ships usin

244、g hydrogen as fuel Further develop/finalize guidelines for ships using ammonia as fuel913 September 2024CCC 10 Prepare amendments to the IGF Code on natural gas Finalize guidelines for ships using hydrogen as fuel Finalize guidelines for ships using ammonia as fuel If time permits,further develop gu

245、idelines for low-flashpoint oil fuels If time permits,begin the discussion on the development of mandatory instruments regarding methyl/ethyl alcohols1620 September 2024MSC 109 Approval of the guidelines for ships using hydrogen as fuel Approval of the guidelines for ships using ammonia as fuel26 De

246、cember 2024CCC 11 Further develop/finalize guidelines for low-flashpoint oil fuels If time permits,develop mandatory instruments regarding methyl/ethyl alcohols If time permits,begin the discussion on the development of mandatory instruments regarding fuel cells September 2025MSC 111 Approval of the

247、 guidelines for low-flashpoint oil fuels May 2026CCC 12 Further develop/finalize mandatory instruments regarding methyl/ethyl alcohols Further consider the development of mandatory instruments regarding fuel cells September 2026Table 2:CCC 9 work plan for the development of safety provisions for alt

248、ernative fuels.DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 24ABS embeds into our Rules the two IMO codes related to the carriage and use of natural gas and other low-flashpoint fuels.The IGC Code is incorporated under Part 5C,Chapter 8 of the ABS MVR for specific vessel types,Vessels Intended to Carry

249、Liquefied Gases in Bulk,and the IGF Code under Part 5C,Chapter 13 for Vessels Using Gases or other Low-Flashpoint Fuels.Part 5C,Chapter 8,and Chapter 13 of the Rules incorporate additional ABS requirements and interpretations and applicable IACS unified requirements and interpretations.The text of t

250、he statutory codes is shown in italics to differentiate between the statutory code text and additional ABS or IACS text.ABS provides requirements for the use of alternative and DFs on board:ABS Rules for Building and Classing Marine Vessels(MVR)ABS Requirements for Methanol and Ethanol Fueled Vessel

251、s(2024)ABS Requirements for Ammonia Fueled Vessels(2023)ABS Guide for Gas and Other Low-Flashpoint Fuel Ready Vessels In addition,ABS provides guidance on the topic:ABS Advisory on Gas and Other Low-Flashpoint Fuels ABS Bunkering of Liquefied Natural Gas-Fueled Marine Vessels in North America(Second

252、 Edition)ABS LNG Bunkering:Technical and Operational Advisory ABS Methanol Bunkering:Technical and Operational Advisory(2024)ABS Ammonia Bunkering:Technical and Operational Advisory(2024)ABS Sustainability Whitepaper Ammonia as Marine Fuel(2020)ABS RULES AND REQUIREMENTSDUAL-FUEL SOLUTIONS FOR NEWBU

253、ILD VESSELS 25Climate change or global warming is primarily caused by humans burning fossil fuels,increasing GHGs like CO2 and methane.Greenhouse gases absorb some of the heat that the Earth radiates after it warms from sunlight.Larger amounts of these gases trap more heat in Earths lower atmosphere

254、,causing global warming.The IMO estimates that emissions from shipping in 2050 will range from 1,200 Mt CO2/year in a low-emission scenario to 1,700 Mt CO2/year in a high-emission scenario and have set a target to reduce this.The maritime industry is currently undergoing an energy transition,which i

255、s being driven by the imperative to mitigate climate change and an ever-changing regulatory environment.An unprecedented transition from conventional fossil fuels to alternative energy sources and the implementation of cutting-edge technologies define the sectors endeavors.A number of initiatives ai

256、med at reducing greenhouse gas(GHG)emissions have been implemented or are in the process of being implemented in accordance with the revised GHG Strategy of IMO.The IMO updated its initial strategy at the Marine Environment Protection Committee(MEPC)80th session,which set ambitious goals for future

257、pollution reduction targets compared to 2008 levels.The revised strategy includes the following targets:For carbon intensity:40 percent reduction by 2030 Uptake of zero or near zero technologies,fuels/energy sources by at least 5 percent,striving for 10 percent GHG emissions:Net zero by or around 20

258、50 Indicative checkpoints:20 percent,striving for 30 percent,by 2030 70 percent,striving for 80 percent,by 2040Figure 6:IMO GHG reduction targets.EMISSIONS COMPLIANCETotal Annual GHG EmissionsYearIMO GHG Reduction Targets200020100%20%40%60%80%100%202020302040205020602008BenchmarkYearReduction of CO2

259、 emissions per transport work,by at least 40%,compared to 2008Reach net-zero GHG emissions by or around 2050Uptake of zero or near-zero GHG emissionfuels at least 5%,striving for 10%20%,striving for 30%reduction70%,striving for 80%reductionDUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 26In addition,marke

260、t-based measures(MBMs)are included in the strategy to incentivize GHG reduction.Several MBMs have been proposed,and MEPC 81 did not provide clarity on which of the candidate measures may be implemented,but it is ABS opinion that the IMO may follow the EU with a carbon tax and a WtW measure based on

261、GHG intensity.The GHG Fuel Standard(GFS)is under development and expected to be implemented no earlier than 2027.In addition to the potential MBMs considered by the IMO,the EU has created the Fit for 55 legislative package,aiming to reduce EU GHG emissions by 55 percent by 2030.This package includes

262、 the addition of the EU Emissions Trading Scheme(EU ETS)and FuelEU Maritime regulation,with EU ETS implemented in 2024 and FuelEU Maritime beginning at the start of 2025.These measures apply to voyages of vessels arriving and departing the EU and sailing from EU port to EU port,with a voyage defined

263、 as cargo operation to cargo operation.The EU ETS is an emissions trading scheme,in which emitters will have to buy allowances to cover their CO2 emissions.These allowances are bought and sold,and speculation may lead to price volatility.As more details of the regulation have come to light with its

264、adoption,it has become apparent that the shipowner submitting the allowances to the EU may be reimbursed by the charterer.As such,the cost of EU ETS may now affect charter rates,as vessels emitting more CO2 may cost the charter more when transporting their cargo,which may provide benefits for DF ves

265、sels.It is worth noting that from 2026 onward,the CO2e from N2O will be included in the cost of the EU ETS,which may affect LNG and ammonia-fueled vessels.FuelEU Maritime imposes a yearly GHG limit with annual reduction targets,which will become more ambitious leading up to 2050 to reflect developme

266、nts in low-carbon fuel technology and availability.Ships will need to calculate GHG emissions per unit of energy used on board based on their reported fuel consumption and the emissions factors of their respective fuels.FuelEU Maritime adopts a WtW approach to assessing a fuels emissions factor,whic

267、h covers the entire life cycle.The calculated GHG emission intensity greatly depends on the fuel type mix used on board the vessel.This is then compared to the index value.Ships that do not meet the required yearly index will be subject to penalties,whereas meeting the yearly target will lead to cre

268、dits being allocated.DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 27Figure 7:GHG intensity limit.Year2020202520302035204020452050Reduction-2%-6%-14.5%-31%-62%-80%GHG intensity gCO2e/MJ91.1689.3485.6977.9462.9034.6418.23Table 3:GHG intensity reductions.FuelEU Maritime allows for some flexibility.Rolling

269、over or borrowing excess compliance from one year to another,or pooling compliance between multiple vessels is possible.If a ship has a deficit of compliance units,some may be obtained in advance,though not for over 2 percent of the target,or over two consecutive reporting periods.100908070605040302

270、0100201520202025203020352040204520502055GHG Intensity Limit(2020 Reference 91.16 gCO2eq/MJ)91.1689.3485.6977.9462.9034.6418.23YeargCO2eq/MJDUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 28DF EFFECTS ON EU ETSAs EU ETS is based on GHG emissions generated on board the vessel,two paths are available to reduc

271、e exposure to EU ETS:Reduce fuel consumption Reduce the carbon factor of the fuelReducing fuel consumption will provide easy but small gains,while larger gains will be difficult to achieve.Changing to alternative fuels will reduce the carbon factor and the number of EU Allowances(EUAs)required.The r

272、eduction will depend on the carbon factor and LCV of the fuel to be used,for example:LNG-fueled vessel:approx.25 percent reduction(depending on methane slip)Methanol-fueled vessel:approx.15 percent reduction Ammonia-fueled vessel:approx.80 percent reduction(depending on pilot fuel and N2O slip)As th

273、ese reductions may be passed on to the charter,it may be that better charter rates can be negotiated for DF vessels.Conversely,ABS expects charter rates for conventional vessels to start decreasing in the upcoming years.DF EFFECTS ON FUELEU MARITIMEAs FuelEU Maritime considers WtW emissions,the type

274、 of fuel(gray,blue or green)is of major importance.These fuel types are defined as follows:Gray Fuel:Conventional fuel produced from refining hydrocarbons.The vast majority of fuels used in shipping are gray fuels.Blue Fuel:Similar to gray fuels,but with carbon capture used during the refining proce

275、ss to reduce the amount of CO2 generated during fuel production(WtT emissions).This does not affect the emissions during use on board the vessel(TtW emissions).Green Fuel:Either biofuels or synthetic fuels(created from electrolysis of water using green electricity,e-fuels),which have very low emissi

276、ons during production.COST OF COMPLIANCE 29DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELSWhen considering the effect of alternative fuels on FuelEU Maritime,it is useful to refer to the graph below:Figure 8:GHG intensity limit and most common fuels.Using the graph,we can now discuss each DF option:DF LNG:

277、For DF LNG,the most popular engine type(due to lower methane slip),is the two-stroke Diesel Cycle type.This is what we will concentrate on here.Due to the low WtT emissions and TtW emissions that are approximately 25 percent lower than conventional fuels,a WtW GHG intensity of 76.1 grams of carbon d

278、ioxide equivalent per megajoule IgCO2e/MJ)is obtained.This will provide compliance(compliance surplus)with FuelEU Maritime until 2040.Associated with this compliance surplus is the possibility to offset compliance deficits for other vessels by pooling.For compliance beyond 2040,the addition of bioga

279、s(30 percent bio-LNG in the graph)will provide further compliance surplus until 2045,and a larger compliance surplus prior to 2040.DF methanol:For DF methanol,using gray methanol(102.9 gCO2e/MJ)will create issues with compliance,generating a compliance deficit from 2025.For compliance,green(bio or e

280、-methanol)or blue methanol must be used,possibly as a blend,and the percentage adjusted as and when needed.Looking at the graph above,30 percent of e-methanol will provide compliance and a surplus to 2040.DF ammonia:For DF ammonia,as ammonia does not generate any emissions when combusted on the vess

281、el(TtW)except for the emissions from pilot fuel use,almost all the WtW emissions from a DF ammonia vessel are generated from the production of the fuel.The type of ammonia therefore has the largest effect on FuelEU Maritime regulations.Using gray ammonia(121 gCO2e/MJ)will lead to higher compliance c

282、osts than gray methanol.Green ammonia(approximately 8 gCO2e/MJ)will provide a very large compliance surplus up to 2050,which may offset GHG emissions of many vessels and offset the increased cost of expensive green ammonia.GHG Intensity gCO2e/MJHFOLFOMDO/MGOLNG(LP 4S Otto)LNG(LP 2S Otto)LNG(HP 2S Di

283、esel)LNG(Steam)LPG(Butane)Hydrogen(NG)Ammonia(NG)Methanol(NG)30%WCO and 70%LFO*30%Bio-LNG(HP 2S Diesel)*30%e-Methanol*120100806040200*e-Methanol(89%GHG reduction)*Hydrotreated oil from waste cooking oil(80%GHG reduction)*Biomethane for transport(Open digestate,no of-gas combustion)(69%GHG reduction)

284、Well-to-TankTank-to-WakeWell-to-WakeGHG Intensity gCO2e/MJ2050204520402035 2030 2020202513.578.291.791.490.889.282.976.174.978.276.470.764.457.614.418.518.518.575.256.718.531.371.9-6.678.271.60.4132.4124.0103.2121.03.07.867.15.062.376.257.34.371.913.2132.0 30DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELSD

285、F EFFECTS ON IMO GHG MBMSAs stated on page 23,as the IMO hasnt concluded on which MBMs will be adopted,it is the opinion of ABS that the IMO may follow the EU with a carbon tax and a WtW measure based on GHG intensity and the GFS.This could be approximate to a global application of EU ETS and FuelEU

286、 Maritime.By using this simplification,the conclusions drawn above can be used for the IMO GHG MBMs,but all the costs and effects would be amplified,namely:Carbon tax:LNG-fueled vessel:approximately 25 percent reduction(depending on methane slip)Methanol-fueled vessel:approximately 15 percent reduct

287、ion Ammonia-fueled vessel:approximately 80 percent reduction(depending on pilot fuel and N2O slip)GFS,assuming similar targets to FuelEU Maritime:DF LNG:Due to the low WtT emissions and TtW emissions that are approximately 25 percent lower than conventional fuels,a WtW GHG intensity of approximately

288、 76 gCO2e/MJ is obtained.This may provide compliance until 2040.For compliance beyond 2040,the addition of biogas may provide further compliance surplus.DF methanol:Using gray methanol(approximately 103 gCO2e/MJ)will create issues with compliance from the adoption of GFS.For compliance,green(bio or

289、e-methanol)or blue methanol must be used,possibly as a blend and the percentage adjusted as and when needed.DF ammonia:For DF ammonia,the type of ammonia has the largest effect on compliance.Using gray ammonia(120 gCO2e/MJ)will create bigger issues with compliance than gray methanol.Green ammonia(ap

290、proximately 8 gCO2e/MJ)may provide compliance to 2050.ECONOMIC ANALYSIS OF CANDIDATE DF VESSEL OPTIONSWhen considering the costs associated with selecting a DF vessel,comparing these costs to the expected cost of an equivalent conventional vessel is beneficial.Four categories must be considered:Fuel

291、 costs Regulatory compliance costs Investment cost(and payback)CharteringEach will be considered in the following table.31DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELSRegarding the fuel costs,comparing the estimated evolution of very low sulfur fuel oil(VLSFO),methanol and ammonia in dollars per metric t

292、on leads to the following table.Data for gray fuels is not shown as the expected FuelEU Maritime(and GFS)penalties will render these fuels uncompetitive:Fuel Type202520302035204020452050VLSFO$650/MT$550/MT$500/MT$480/MTLNGLNG$800/MT$550/MT$540/MT$540/MT$530/MT$530/MTBiogas$1,100/MT$1,060/MT$990/MT$9

293、30/MT$860/MT$800/MTe-LNG$2,700/MT$2,200/MT$2,000/MT$1,800/MT$1,500/MT$1,200/MTMethanolBiomethanol$710/MT$600/MT$550/MT$520/MT$480/MT$460/MTSynthetic(e-fuel)$1,400/MT$1,100/MT$990/MT$850/MT$700/MT$570/MTAmmoniaBlue$670/MT$500/MT$490/MT$480/MT$470/MT$460/MTGreen$950/MT$650/MT$580/MT$510/MT$430/MT$350/

294、MTTable 4:Estimated evolution of fuel costs.The costs are obtained from various sources in the industry and combined with internal ABS data.It is worth noting that approximately 1.7 times more methanol is needed and two times more ammonia compared to a conventional vessel.Pilot fuel(5 to 15 percent)

295、should also be considered.Subsidies may be made available to reduce the cost of these lower and zero-carbon fuels,but more information isnt currently available.For the regulatory compliance costs,pages 26,27 and 28 provide the information required to estimate the cost effect.As these costs will dire

296、ctly depend on the fuel type and consumption,a simpler way to present the cost effects is to compare to the base VLSFO case.32DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELSThen a“+”can be used to show a higher cost of compliance than VLSFO and a“”to show a lower cost.Multiples of each are used to facilita

297、te the comparison.Fuel TypeEU ETSFuelEUIMO Carbon TaxIMO GFSVLSFO0000LNGLNG-Biogas-e-LNG-MethanolGray-+-+Green-AmmoniaGray-+-+Blue-Green-Table 5:Regulatory compliance cost comparison.For FuelEU Maritime(and maybe GFS),pooling will help monetize the compliance surplus.Regarding the investment costs a

298、nd the payback of the investment in a DF vessel,we can look at each option in turn:DF LNG:Due to the properties of the LNG,this is potentially the most expensive of the DF vessels for the fuel containment and FSS(usually Type C tanks and high-pressure pumps).The main machinery cost might be similar

299、to ammonia machinery.DF methanol:As methanol is liquid at ambient temperature,it is the cheapest and easiest system considered here(special coatings and cofferdams around the fuel tanks).DF ammonia:As the temperature needed to liquify ammonia is higher than the temperature for LNG,containment and fu

300、el supply costs may be lower than the equivalent LNG vessel.Regarding the payback of the investment,various techno-economic analysis undertaken by ABS show that selling an existing vessel and replacing it with a DF vessel will not repay the investment.But if the comparison is the replacement of a ve

301、ssel with a conventional or a DF vessel,in most cases,there is a breakeven point between the conventional and DF of 10 to 18 years if the vessel sails sufficiently in the EU for the regulatory advantages of the DF vessel to be monetized.The adoption of the IMO GHG MBMs would potentially reduce this

302、due to the global application of the MBMs.This also considers the potential chartering advantages.When considering the chartering effects,with the shipowner being able to recoup the cost of the EUAs from the charterer,it is apparent that charter rates for conventional vessels visiting the EU will dr

303、op over the next few years.This is not expected to happen for DF vessels due to their reduced compliance cost.33DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELSCONCLUSIONThree main DF solutions are considered by international shipping:DF LNG,DF methanol and DF ammonia.The selection of the most suitable tech

304、nology requires the consideration of multiple factors,which were elaborated in detail in the main body of this advisory.An overall view of the characteristics of the three alternative fuels is shown below compared to MGO:FuelBoiling Point(C)InfrastructureTtW CO2 emissionsWtW CO2 emissions*Technology

305、 Readiness LevelImpact on Newbuilding Ship CostAmmonia-33 Existing LPG network can be used 700 LPG carrierNoneClose to Zero6MediumMethanol65 Infrastructure in place Available in many portsApprox 15%lower than MGOClose to zero(even negative)8-91.9LNG(Methane)-163 Infrastructure under develop Costly t

306、o transport*Approx 25%lower than MGO(depending on slip)Difficult to reach zero9High*Possibility to use small LNG carriers as bunker vessels.The situation is improving.*Fuel produced from either sustainable biomass and/or renewable electricityTable 6:Overall characteristics of alternative fuel.34DUAL

307、-FUEL SOLUTIONS FOR NEWBUILD VESSELSThe table below summarizes the points requiring further attention when considering the building of a DF vessel:DF LNGDF MethanolDF AmmoniaNon-hazardous machinery space is selected to reduce vessel complexity and cost.To protect methanol tank vapor space from explo

308、sive behavior,nitrogen gas is to be used to blanket methanol.It is critical that equipment and system design decisions consider the interdependence between the fuel storage,fuel preparation and fuel consumer.Refer to the ABS Guidance Notes on Gas Dispersion Studies of Gas Fueled Vessels.Flame detect

309、ion equipment such as IR cameras,foam extinguishing systems and robust operational procedures are to be in place to protect against methanol fires.Refer to ABS MVR 5C-18-6/3.3.3 for initial guidance when conceptualizing the design of mechanical ventilation of the spaces where ammonia is used and sto

310、red.As per most gas-fueled ships in operation,it is recommended to select IMO Type C pressurized fuel tanks.The handling of methanol is to be carried out carefully as it contrasts with conventional marine fuels by its high toxicity and danger to humans.For ammonia tanks,risk assessment should consid

311、er the requirements of the IGC and IGF Codes.If a membrane tank is used,other considerations will need to be addressed(such as choice of material for the surrounding hull,a more complex BOG management system and upscaling the nitrogen gas generating system).Methanol is corrosive in the presence of a

312、luminum and titanium alloys,which are commonly used in fuel systems for natural gas and distillate fuels.Special attention is required to the engine type selected due to the pros and cons of each type.Natural BOR to be provided for the tank and BOG management protocols to be presented,(IGF Code 15-d

313、ay criteria).For practical reasons,consider duplication of rotating and reciprocating FGSS equipment(submerged LNG pumps or high-pressure cryogenic pumps).The bunkering station is to be provided with adequate ventilation and is to be preferably located on the open deck.When bunkering ammonia,measure

314、s need to be taken to avoid leakage,handle toxicity and maintain equipment in good working condition through regular inspection.Methanol is often proposed for locations below the waterline.This can promote the use of several ballast tanks as potential fuel tanks with additional cofferdams or hold sp

315、aces also required.Bunkering is to be considered at the beginning of a design project for optimum design results.If blending water with methanol to achieve NOx Tier III,a separate NOx compliant aftertreatment system is required to achieve NOx Tier III compliance when in fuel oil mode.Table 7:Points

316、requiring further attention when considering the building of a DF vessel.DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 35As the main goal for the adoption of a DF vessel is emission compliance,it is important to consider the costs of this compliance,both in terms of potential savings from compliance and

317、additional costs from operation and investment for each of the three options presented in this report.DF LNGDF MethanolDF AmmoniaEU ETS/IMO Carbon Tax-25%cost compared to MGO-15%cost compared to MGOApproximately-80%cost compared to MGOFuelEU Maritime/IMO GFSGray LNG:Compliance to 2040Green LNG:Compl

318、iance to 2045+Gray Methanol:Non-compliantGreen Methanol:Compliance to 2050Gray Ammonia:Non-compliantGreen Ammonia:Compliance to 2050Fuel Cost*LNGBio-MethanolBlue Ammonia2025$800/MT$710/MT$670/MT2035$540/MT$550/MT$490/MT2045$530/MT$480/MT$470/MTFuel Cost*BiogasSynthetic MethanolGreen Ammonia2025$1,10

319、0/MT$1,400/MT$950/MT2035$990/MT$990/MT$580/MT2045$860/MT$700/MT$430/MTDF LNGDF MethanolDF AmmoniaInvestment CostHighestMediumHigh*Cost per Mt.Due to LCV,1.7 to 1.9 times more methanol is needed for the same energy,2 to 2.2 times more ammonia is needed for the same energy.Table 8:Overall cost compari

320、son.DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS 36LIST OF ACRONYMS AND ABBREVIATIONSBOG Boil-off gasBOR Boil-off-rateCCTV Closed-circuit televisionCO2 Carbon dioxideDF Dual fuelEPA Environmental Protection AgencyESD Emergency shutdown EU European Union EU ETS European Union Emission Trading SchemeEUA E

321、uropean Union Allowances FGSS Fuel gas supply systemFSS Fuel supply systemGFS Greenhouse gas fuel standardGHG Greenhouse gasGVU Gas valve unitHFO Heavy fuel oilIACS International Association of Classification SocietiesIARC International Agency for Research on CancerIBC International Code for the Con

322、struction and Equipment of Ships Carrying Dangerous Chemical in BulkIGF Code International Code of Safety for Ships Using Gases or other Low-Flashpoint FuelsIMO International Maritime organizationIR InfraredIRENA International Renewable Energy AgencyLCV Lower calorific valueLNG Liquefied natural gas

323、LPG Liquefied petroleum gasm MetersMARPOL International Convention for the Prevention of Pollution from ShipsMBMs Market-based measuresMCR Maximum continuous ratingMDO Marine diesel oilMGO Marine gas oilMt Million metric tonsmtpa Million tonnes per annumN2O Nitrous oxideNOx Nitrogen oxideNTC NOx Tec

324、hnical CodeOEM Original equipment manufacturerOSV Offshore support vesselPEM Polymer electrolyte membraneppm Parts per millionSCR Selective catalytic reductionSOFC Solid oxide fuel cellTtW Tank-to-WakeUI Unified InterpretationUSCG United States Coast GuardVLSFO Very low sulfur fuel oilWtT Well-to-TankWtW Well-to-Wake 37DUAL-FUEL SOLUTIONS FOR NEWBUILD VESSELS1701 City Plaza Drive|Spring,TX 77389 USA1-281-877-6000|sustainabilityeagle.orgwww.eagle.org 2025 American Bureau of Shipping.All rights reserved.