alternative fuels for marine application
TRANSCRIPT
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Alternative Fuels forMarine Applications
Annex 41
Ralph McGill
Fuels, Engines, and Emissions Consulting
William (Bill) Remley
Alion Science and Technology
Kim Winther
Danish Technological Institute
A Report from the IEA Advanced Motor Fuels Implementing Agreement
May 2013
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Alternative Fuels forMarine Applications
Annex 41
Ralph McGill
Fuels, Engines, and Emissions Consulting
William (Bill) Remley
Alion Science and Technology
Kim Winther
Danish Technological Institute
A Report from the IEA Advanced Motor Fuels Implementing Agreement
May 2013
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Acknowledgment
TheIEAAMFOrganizationisgratefultothefollowingcountriesandtheir
representativesfortheirsupportinprovidingfundingfortheresearchtodevelopthisreport.Theworkhasbeenmostinterestingandinformative.
DenmarkJesperSchramm,TechnicalUniversityofDenmark(DTU)FinlandNilsOlofNylund,TheTechnicalResearchCentreofFinland(VTT)GermanyBirgerKerckow,FachagenturNachwachsendeRohstoffe(FNR)
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TableofContents
Acknowledgment................................................................................................. i
Acronymsand
Abbreviations
................................................................................
vii
ExecutiveSummaryAnnex41............................................................................ xi
1. Introduction.................................................................................................. 1
2. Background................................................................................................... 3
3. CurrentSituation........................................................................................... 9
3.1 LegislationforMarineSOxReduction......................................................... 93.2 LegislationforMarineNOxReduction........................................................ 93.3 CompliancewithMarineSOxandNOxLegislation..................................... 11
4. FuelPricesandAvailability............................................................................ 13
4.1 CurrentMarineFuels.................................................................................. 134.2 GlobalFuelConsumptionbyVesselType................................................... 154.3 FuelCost...................................................................................................... 16
5. AlternativeMarineFuelIncentives................................................................. 19
6. AlternativeMarineFuelsandEngines............................................................ 21
6.1 LiquidorCrudeBasedFossilFuels.............................................................. 226.2 LiquidBiofuels............................................................................................. 24
6.2.1 Methanol......................................................................................... 256.2.2 Biocrude.......................................................................................... 26
6.3 GaseousFuels.............................................................................................. 276.4 ExhaustGasTreatmentSystems................................................................. 297. AssessingAlternativeFuelsforMarineUse.................................................... 33
7.1 LiquidFossilFuelsAdvantages.................................................................... 337.1.1 FuelSystemandEngineCompatibility............................................ 337.1.2 LowerSOxEmissions....................................................................... 347.1.3 Safety............................................................................................... 347.1.4 Availability....................................................................................... 34
7.2 LiquidFossilFuelsDrawbacks..................................................................... 34
7.2.1 Price................................................................................................. 347.2.2 Characteristics................................................................................. 357.2.3 FutureAvailability........................................................................... 35
7.3 LiquidBiofuelsCharacteristics.................................................................... 367.3.1 BiodieselAdvantages...................................................................... 367.3.2 BiodieselDrawbacks........................................................................ 367.3.3 AlgaeFuelsAdvantages................................................................... 377.3.4 AlgaeFuelDrawbacks...................................................................... 397.3.5 HydrogenationDerivedRenewableDieselAdvantages.................. 39
7.3.6 HDRDDrawbacks............................................................................. 407.4 GaseousFuels:NaturalGas......................................................................... 407.4.1 NaturalGasAdvantages.................................................................. 407.4.2 NaturalGasDrawbacks................................................................... 42
7.5 FutureMarineFuelUse............................................................................... 55
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8. VesselsUsingAlternativeFuels...................................................................... 57
8.1 VesselsUsingULSDandLSRF...................................................................... 578.2 VesselsUsingNaturalGas........................................................................... 57
8.2.1 LargeShips....................................................................................... 63
8.3 VesselsUsingLiquidBiofuels....................................................................... 649. TheWayForwardforFutureMarineFuels..................................................... 679.1 BreakEvenPoints....................................................................................... 68
10. Conclusions................................................................................................... 71
11. Recommendations......................................................................................... 75
References........................................................................................................... 77
AppendixAMarineAfterExhaustTreatmentSystems....................................... 83
A.1 SelectiveCatalyticReductionandExhaustGasRecirculationSystems....... 83A.2 ScrubberSystems........................................................................................ 85
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ListofFigures
1. CurrentandPossibleFutureECAs........................................................................ 4
2. NorthEuropeanSECAEffectiveasofAugust11,2007......................................... 53. ShipOperatorsChallenges................................................................................... 64. IMODieselEngineNOxEmissionLimits............................................................... 105. GlobalMarineFuelConsumptionEstimates,IMO2009....................................... 136. TypicalHeavyMarineFuelTypeDistribution....................................................... 147. TheTotalWorldMarineFleetAccordingtoIMO................................................. 158. WorldBunkerFuelDemand................................................................................. 159. BunkerworldIndexPricesofHFSO380andMDO................................................ 1610. CostofLighterLowSulphurFuelsComparedtoHighSulphurBunkerFuel........ 17
11. SulfurContentofConventionalMarineFuels...................................................... 2212. WrtsilDirectInjectionDualFuelConceptforMethanolinLargeFourStrokeEngines.............................................................................................. 26
13. WrtsilPortInjectionDualFuelConceptforGasUseinLargeFourStrokeEngines.............................................................................................. 29
14. CostsofScrubberSystems[CoupleSystems,AlfaLaval]...................................... 3115. ProjectedPricesofMarineFuels.......................................................................... 4116. WeightsandVolumesofMarineFuels................................................................. 4417. LNGBunkeringShipSeagasalongsidetheVikingGrace................................... 46
18. ExistingandPlannedProductionPlantsandLNGTerminalsintheSECA............. 5319. LNGBunkeringBarge............................................................................................ 5520. BitVikingwithLNGFuelTanksontheMainDeck............................................. 6121. LNGTanksonTopDeckofWSFIssaquahClassFerry........................................... 6222. ConceptIllustrationofTOTEContainerShip........................................................ 6423. FuelSelectionProcessisResponsibilityoftheChartererand
IsInfluencedbyManyFactors.............................................................................. 6824. BreakEvenAnalysisforScrubberInstallationon38,500dwtTankers................ 69A1.SCRSolutionbyMAN............................................................................................ 83
A2.AdvancedEGRSystembyMAN............................................................................ 84A3.ScrubberSystembyAlfaLaval.............................................................................. 85A4.FicariaSeawaysEquippedwithPresumablyWorldsLargest
RetrofitScrubberin2009..................................................................................... 86A5.ClosedLoopScrubberbyWrtsil........................................................................ 86A6.DryScrubberSystembyCoupleSystems,Germany............................................. 87
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ListofTables
1. MARPOLAnnexVIMarineSOxEmissionReductionAreaswith
FuelSulfurLimits.................................................................................................. 92. MARPOLAnnexVINOxEmissionLimits............................................................... 103. GlobalMarineFuelUseEstimatedfromIMOandSingaporePort
BunkeringStatistics2009...................................................................................... 144. FeedstocksandDerivedFuels............................................................................... 215. MarineFuelPricesinJuly2012inUSD/MetricTonbyPort................................. 356. Comparisonof50/50BlendofAlgaeandF76PetroleumFuelwith
PetroleumF76..................................................................................................... 387. CostsAssociatedwithConvertingMarineVesselstoLNGOperation.................. 43
8. FuelUsageandStorageVolumesforThreeTypesofVessels.............................. 449. BarrierstoIntroductionofLNGandPossibleActions.......................................... 5210. 2020MarineFuelMix........................................................................................... 5611. LNGUsageLevelsfortheBase,High,andLowCasesPredictedby
LoydsRegister...................................................................................................... 5612. CurrentOrderBookforNewLNGFueledVessels................................................ 5913. SummaryofEvaluationofPropellantSystems..................................................... 72
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AcronymsandAbbreviations
ABS AmericanBureauofShipping
ASTM AmericanSocietyforTestingandMaterials
BN basenumberBTL biomasstoliquidBV BureauVeritas
CCS ChineseClassificationSocietyCCW CaliforniaCoastalWatersCO2 carbondioxide
CNG compressednaturalgasCNOOC ChinaNationalOffshoreOilCorporationDFDS DetForenedeDampskibsSelskabDME dimethyletherDNV DetNorskeVeritasDSME DaewooShipbuilding&MarineEngineering
ECA EmissionsControlAreaEEDI EnergyEfficiencyDesignIndex
EGCS exhaustgascleaningsystemEGR exhaustgasrecirculationEU EuropeanUnion
FAME fattyacidmethylester
GATE GasAccesstoEuropeGHG greenhousegasGL GermanischerLloyd
GTL gastoliquidGTM GreenTechMarine
HDRD hydrogenationderivedrenewabledieselHFO heavyfueloilHRD hydrotreatedrenewablediesel
ICS InternationalChamberofShippingIF intermediatefuel
IFO intermediatefueloilIMO InternationalMaritimeOrganizationISO InternationalStandardsOrganization
JIV jointindustryproject
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JV jointventure
LBG liquefiedbiogasLNG liquefiednaturalgas
LOA lengthoverallLPG liquidpropanegasLR LloydsRegisterLS lowsulfurLSFO lowsulfurfueloilLSRF lowsulfurresidualfuel
MARPOL marinepollution;thus,theInternationalConventionforthePreventionofPollutionfromShips
MBM marketbasedmeasureMDO marinedieseloilMEGI mainenginegasinjectionMGO marinegasoilMnT milliontonnesMSAR2 MulPhaseSuperfineAtomizedResidue
NaOH sodiumhydroxideNOx nitrogenoxides
PM particulatematter
OSV offshoresupplyvessel
REM RemOffshoreRFO residualfueloilRFS RenewableFuelsStandardRMG residualmarinegas
RO/RO rollon,rolloff
S sulfurSABIC SaudiBasicIndustriesCorporationSCR selectivecatalyticreductionSECA SOxEmissionControlAreasSI sparkignitionSOx sulfuroxideSTQ SocietedestraversiersduQuebec
TENT TransEuropeanTransportNetworkTOTE TotemOceanTrailerExpress
ULSD ultralowsulfurdiesel
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USD U.S.dollar(s)
WSF WashingtonStateFerries
UnitsofMeasure
cSt centistokes
dwt deadweightton(s)
g gram(s)
HP horsepower
kg kilogram(s)km kilometer(s)kW kilowatt(s)kWh kilowatthour(s)
m meter(s)MJ megajoule
MT Megaton;MetricTonMW megawatt(s)
nm nauticalmiles
ppm partspermillionpsi poundspersquareinch
rpm rotationsperminute
TEU twentyfootequivalentunit
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ExecutiveSummaryAnnex41
Themarine shipping industry is facing challenges to reduceengineexhaustemissions
and greenhouse gases (GHGs) in particular, carbon dioxide (CO2) from their ships.International regulatorybodiessuchas the InternationalMaritimeOrganization (IMO)and national environmental agencies of many countries have issued rules andregulationsthatdrasticallyreduceGHGandemissionsemanatingfrommarinesources.Thesenewrulesare impactingships thatengage in internationalandcoastalshippingtrade, the cruise industry, and ship owners and operators. Of particular note areregulations inEmissionsControlAreas (ECAs) suchas theNorthAmericanECA,whichcameintobeingin2012,andtheSOxEmissionControlAreas(SECAs),whichhavebeenin effect in the Baltic Sea and North Sea and English Channel since 2006 and 2007,
respectively. Ships operating in the ECAs and SECAs are required to use lower sulfurfuelsoraddsulfuroxide (SOx)exhaustscrubbers. It isalsoexpected that futureECAswillbecoming intoeffect incountries that seeheavy ship traffic.Effectingneartermlocal(SECA/ECAdriven)nitrogenoxide(NOx)andSOxreductions isthemostpressingissue as a result of these regulations. Over the longer term, addressing GHG andparticulatematter(PM)emissionswillprovidefurtherenvironmentalchallenges.
Manyshipoperators,withpresentdaypropulsionplantsandmarinefuels,cannotmeetthesenew regulationswithout installingexpensiveexhaustaftertreatmentequipment
orswitchingtolowsulfurdiesel,lowsulfurresidual,oralternativefuelswithpropertiesthat reduceengineemissionsbelowmandated limits,allofwhich impactbottomlineprofits.Theimpactofthesenewnationalandinternationalregulationsontheshippingindustries worldwide has brought alternative fuels to the forefront as a means forrealizing compliance. The alternative fuels industry has grown dramatically for bothliquid and gaseous fuels. Each of these alternative fuels has advantages anddisadvantagesfromthestandpointoftheshippingindustry.
Thisreportexaminestheuseofalternativefuelsforusebythemarineshippingindustry
to satisfy or partially satisfy the new emissions and fuel sulfur limits. It also looks atexhaustaftertreatmentdevicesthatcanbeusedtolowertheengineexhaustemissions.
Alargepartofthemarinefuelconsumption(approximately77%)isoflowquality,lowpriceresidual fuelreferredtoasheavyfueloil(HFO),whichtendstobehigh insulfurand isalmostentirelyconsumedby largecargocarryingships.Theaverage fuelsulfurcontentofHFOusedtodayformarinedieselenginesis2.7%withamaximumallowablelimitof4.5%,whichpresentschallengesastherequiredfuelsulfurlevelsforuseintheECAsandglobally are lower.Almost90%of theworlds marine fuel isusedby cargo
ships.Thisreportdealsonlywithfuelssuitableforheavydutydieselenginesprovidingpropulsionandauxiliaryenergyon commercial shipswhich is thebulkofmarine fuelconsumption.
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Currently,themostpracticalsolutionistouselowsulfurfuelswheninanECAandothersituationsrequiringuseoflowsulfurfuels.Thereareliquidbiofuelsandfossilfuelsthatare low insulfurandcansatisfythefuelsulfurrequirementsoftheECAsandMARPOL(InternationalConventionforthePreventionofPollutionfromShips)AnnexVI.Inlieuof
usinglowsulfurliquidfuels,anotheroptionistheuseofscrubbersfittedintheengineexhausttoremovetheSOx.
This report examines a variety of liquid fossil and biofuels. Liquid biofuels that areavailable for marine use are biodiesel; fatty acid methyl ester (FAME); algae fuels;methanol; hydrogenationderived renewable diesel (HDRD), which is also known assecondgeneration biodiesel; and pyrolysis oil. The advantages and disadvantages ofthesefuelsformarineusearediscussed.
TheaftertreatmentapproachformeetingtheNOxandSOxlimitsistoinstallemissioncompliantenginesor selective catalytic reduction (SCR)equipment forNOx reductionandexhaustaftertreatmentdevicesknowasscrubbersforSOxreduction.Whenlookingat these technologies, the cost tradeoffs for their installation, operation, andmaintenanceversus thecostsof thealternative fuelsmustbeconsidered.The reportdiscussestheeconomicsandbreakevenpointforusingscrubbersversusconventionalfossilfuelsbasedonoperationswithinanECA.
Gaseousfuelsareanotheroptionbutrequireadifferenttypeof fuelhandlingsystem,
fuel tanks and gas burning engines that are not currently in use on most ships. Thegaseous fuels that are available for marine use are natural gas and propane (liquidpropanegas [LPG]).Notonlyare these fuelsvery low insulfurcontent, theycombustsuch that NOx, PM, and CO2 are also reduced. Natural gas can be carried as acompressedfuelcalledcompressednaturalgas(CNG)orinaliquidstatecalledliquefiednaturalgas(LNG).
Currently,thepriceofnaturalgasisveryattractiveandassuchisagoodcandidateforservingasashipsfuel.Thereareanumberofshipsthathavebeenbuilttousenatural
gasasfuel,mostlyinthecoastwisetradeoronfixedroutessuchasferries.
Atpresent,vesselsusingnaturalgasasa fuelare in the small tomediumsize rangewithlargershipsbeingbuiltorconvertedforoperationonLNGfuel.TheonlylargeshipscurrentlyusingLNGasafueloninternationalvoyagesareLNGcargocarriers.
ForLNGtobecomeanattractivefuelforthemajorityofships,aglobalnetworkofLNGbunkeringterminalsmustbeestablishedorLNGfueledshipswillbe limitedtocoastaltradeswherethereisanLNGbunkeringnetwork.Thesituationissometimesdescribed
asachickenandeggdilemma.Untilthebunkeringinfrastructureisinplace,theshipownersmaynotcommittooperatingnaturalgasfueledshipsandvisaversa.Currently,LNGbunkeringismoreexpensiveandcomplicatedthanfossilfuelbunkeringandisonlyavailableinalimitednumberofplaces.TheportofStockholm,Sweden,hasestablished
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anLNGbunkeringportwithdocksidefuelingandaspecialpurposeshipthatperformsshiptoshipLNGfueling.
As the shipping industry considers alternatives to HFO, part of the market will shift
towardmarinegasoil (MGO)andpart towardLNGorotheralternative fuels.Marinevesselsequippedwith scrubberswill retain theadvantageofusing lowerpricedHFO.Shipping that takes place outside ECA areas might choose HFO or lowsulfur fuel oil(LSFO)dependingonfutureglobalregulations.Shipsoperatingpartly inECAareaswillprobablychooseMGOasacompliancefuel.HeavyshippingwithinECAareas,however,mightbeincentiveenoughforacompleteshifttoLNG.
Compliance with the new emission requirements will raise operating costs for shipowners and operators in terms of new construction ships that will have more
complicatedfuelsystemsandperhapsaftertreatmentdevicesandmoreexpensivelowsulfurfuelswhenintheECAsandotherlowsulfurcomplianceportsandcoastalwaters.ExistingshipsthatdonothavedualtanksmayhavetoberetrofittedwithdualfossilfuelsystemssotheycanperformfuelswitchingwhentheyenteranECA.
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1. Introduction
Recent sulfur and emissionsrelated limits imposed on fuels used in the shipping
industryarecausingtheindustrytolookatalternativefuelsasawayofcomplyingwiththenewlimits.Thisstudyfocusesonthedetailsofthesenewemissionsrequirements,theirimplementationtimeframes,thetypesofalternativefuelsavailableforcomplyingwiththeserequirements,thecostsofcompliancedependingonthepathwaytaken,andalternativemethods(suchasexhaustgasscrubbers)forloweringtheexhaustemissions.
The report discusses in detail the advantages and disadvantages of liquid fossil andgaseous fuelsandbiofuelsthatareavailable formarineuseandcanhelpshipownersandoperatorscomplywiththefuelsulfurandexhaustemissionlimits.
Also discussed are marine vessels currently using alternative fuels and vessels beingconvertedtouseorbeingbuiltwithonboardpowerpropulsionplantsusingalternativefuels.
Last,thisreportassessesthefutureofalternativemarinefuelsanddrawsconclusions.
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2. Background
Theworlds total liquid fuelsupplycurrentlystandsatapproximately4,000Megatons
(MT)peryear.Marineliquidfuelsconstituteasignificantproportionat300400MTperyear.Almost90%oftheworldsmarinefuel isusedbycargoships.Passengervessels,fishing boats, tug boats, navy ships, and other miscellaneous vessels consume theremaining10%.
Thevastmajorityofshipstodayusedieselenginessimilar inprincipletothose incars,trucks,andlocomotives.However,marinefuelsdifferinmanyaspectsfromautomotiveenginefuels.
Thequalityofmarinefuelsisgenerallymuchlowerandthequalitybandismuchwiderthan are those of landbased fuels. Marine engines must accept many different fuelgradesoftenwithlevelsofhighsulfurcontentthatwouldseriouslyharmthefunctionofexhaust gas recirculation (EGR) and catalyst systems on automotive engines. Theviscosityofmarinefuels isgenerallymuchhigherupto700cSt,whereasroaddieselfuelrarelyexceeds5cSt.Mostmarine fuels thus requirepreheating toenter the fuelsystem.
This finding also means that traditional emissions abatement technologies for road
based transportsuchasdieselparticulate filters,exhaustgasrecirculationsystems,andoxidationcatalystscannoteasilybeusedonships.Therisksofsulfurcorrosionandveryhigh sootemissions call fordifferent solutions suchas scrubbersoralkalinesorptionsystemsasseparatesolutionsorincombinationwithtechnologiesknownfromroadbasedemissionsabatementtechnologies.
Recent domestic and international efforts to reduce the impact of greenhouse gases(GHGs)onclimatechangeandengineemissionsthataffectthehealthofmanyhasledinternational regulatorybodiessuchas the InternationalMaritimeOrganization (IMO)
andnationalenvironmentalagenciestoissuenewrulesandregulationsthatdrasticallyreduceGHGsandemissionsemanatingfrommarinesources.Thesenewruleshavefarreaching implicationsforthe internationalshippingtrade,thecruise industry,andshipowners and operators in particular. Of particular note are regulations in EmissionsControlAreas(ECAs)suchastheNorthAmericanECA,whichwent intoeffect in2012,andtheSOxEmissionControlAreas(SECAs),whichhavebeenineffectontheBalticSeaand North Sea and English Channel since 2006 and 2007, respectively. On August1,2012,enforcementof theNorthAmericanECAcommenced.TheNorthAmericanECAcovers the coastal watersof the UnitedStatesandCanada out to200 nauticalmiles.
Ships operating in the ECAs and SECAs are required to use lowersulfur fuels or addsulfuroxide(SOx)exhaustscrubbers.RegulationsforaCaribbeanECAwillgointoeffectforPuertoRicoand theU.S.Virgin Islands.Allowing for the lead timeassociatedwiththe IMOprocess, theU.S.CaribbeanECAwillbeenforceable in January2014 (Ref.1).ThereisthepotentialthatECAswillbeestablishedfortheNorwegianandBarentsSea,
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MediterraneanSea,Japan,Australia,MexicoandPanama,theArctic,andAntarctica inthe future (Ref.2).The rules for theseareaswillmandate reductions inemissions ofsulfur (S), nitrogen oxides (NOx) and particulate matter (PM). Current and possibleFutureECAsareshowninFigure1.
Figure1. CurrentandPossibleFutureECAs(Source:Ref.2)
Approximately10%oftheworldsshippingoccurswithintheBalticSearegion(Ref.3),whichisshowninFigure2.
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Figure2. NorthEuropeanSECA
EffectiveasofAugust11,2007(Source:Ref.4)
Someoftheregulatoryandcompetitivechallenges facingshipoperatorsareshown in
Figure3.
Elements in Figure 3 are sometimes competing against each other, especially
considering the reduction of NOx, sulfur, and carbon dioxide (CO2). As an example,
achievingareductionofsulfurbyusingawetscrubbermeans increasingpowerusage
significantlytopumpwater,which,intheend,willleadtoanincreaseinCO2emissions,
aswellasotherpollutantsassociatedwithpowerproduction.Similarly,althoughNOx
could be reduced by lowering the combustion temperature, that adjustment reduces
the efficiency of the main engine and hence increases CO2 and sulfur emissions. A
selectivecatalyticreduction(SCR)installationtoreduceNOxuseschemicals,whichalso
deliverapenalty
in
terms
of
CO2emissionsandtheenvironmentandshouldbetaken
intoconsideration.
Possibilitiestoreduceemissionsareinfluencedbythefreightratesthatshipownerscan
obtain and the fuel prices and taxes of the market. The dilemma therefore lies in
devisinganincentivetoincreaseefficiencyandtherebylowershipsfuelconsumption.
Shorttermlocal(SECA/ECA)NOxandSOxreductionsarethemostpressingissues.Over
the longerterm,addressingGHGandPMemissionswillprovidefurtherenvironmental
challenges.
Theshippingindustryalsofacesdiminishingshippingratesandasignificantrise infuel
prices, includingtaxes in the formofmarketbasedmeasures (MBMs)topromote the
reduction of GHG emissions. Another relevant factor is that acquisitions or takeovers
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are common in the marine sector. Ship operators face the risk of takeover by
competitorsiftheyarenotsufficientlystrong.Thereisariskthatoperatorsfocusingtoo
muchonenvironmentalissueswillbetakenoverbystrongercompetitors(Ref.5).
In
particular,
freight
rates
in
2011
and
at
the
beginning
of
2012
were
often
atunprofitable levels for ship owners. Substantial freightrate reductions were reported
within the dry bulk, liquid bulk, and containerized cargo segments. Vessel oversupply
continued to be a driving factor behind reductions in freight rates. Ship operators
attempted torealizesavingsthroughgreatereconomiesofscaleby investing in large
capacityshipsinthetankeranddrybulkmarketsegments(Ref.6).
Incentives in the formofMBMs to reduceGHGemissions from internationalshipping
could result in a fuel levy (tax). The international shipping industry has indicated a
preferencefor
the
fuel
levy
rather
than
an
emissions
trading
scheme
(Ref.
6).
Figure3. ShipOperatorsChallenges
Ship
OperatorsChallenges
NOxReduction
CO2Reduction
FreightRates
FutureFuel Taxes
SulphurReduction
Policing
New Vessels
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Manyshipoperatorswithpresentdaypropulsionplantsandmarinefuelscannotmeetthesenew regulationswithout installingexpensiveexhaustaftertreatmentequipmentorswitchingtolowsulfurdiesel,lowsulfurresidual,oralternativefuelswithpropertiesthat reduceengineemissionsbelowmandated limits,allofwhich impactbottomline
profits.Theimpactofthesenewnationalandinternationalregulationsontheshippingindustries worldwide has brought alternative fuels to the forefront as a means forachieving compliance. The alternative fuels industry has grown dramatically for bothliquid and gaseous fuels. Each of these alternative fuels has advantages anddisadvantagesfromthestandpointoftheshipping industry. It isvitally importantthatthe nations recognize the impact that the new marine regulations will have on theirmarineindustriesandimplementpoliciesthatwillminimizetheseimpactsandpavethewayforsmoothtransitionstouseofalternativemarinefuelsandoperatingproceduresthat will meet GHG and emissions limits withoutjeopardizing international maritime
trade.
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3. CurrentSituation
Worldwide,marinefuelaccountsfor20%oftotalfueloildemand(Ref.7),notingthat
fueloilisexcludinggasoline.Currently,annualglobaldemandformarinefuelisgreaterthan300MTandconsistsofbothdistillateandresidualfuels.Alargepartofthemarinefuel consumption (approximately 77%) is of lowquality, lowprice residual fuel alsoknownas (a.k.a.)heavy fueloil (HFO),which tends tobehigh in sulfurand isalmostentirelyconsumedbylarge,cargocarryingships.TheaveragefuelsulfurcontentoftheHFO formulations used today for marine diesel engines is 2.7% with a maximumallowable limitof4.5% (Ref.8). (SeeFigure11 foraverage fuelsulfur limits.)The fuelmust alsobe heated to lower the viscosity so it flows easilyand then isput throughpurifiersandfilterstoremovecontaminantsbeforeitispumpedtothedieselengines.
3.1 LegislationforMarineSOxReduction
New and existing regulations derived from the International Convention for thePreventionofPollutionfromShips(MARPOL)affectingtheSOxemissionsfromshipsaresummarizedinTable1.
Table1.
MARPOL
Annex
VI
Marine
SOx
Emission
Reduction
Areas
with
Fuel
Sulfur
Limits
Year FuelSulfur(ppm) FuelSulfur(%)
EuropeanSECAs
NorthSea,EnglishChannel
CurrentLimits 10,000 1
2015 1,000 0.1BalticSea CurrentLimits 10,000 1
2015 1,000 0.1NorthAmericanECAsUnitedStates,Canada 2012 10,000 1
2015 1,000 0.1Global 2012 35,000 3.5
2020a 5,000 0.5a Alternativedateis2025,tobedecidedbyareviewin2018.
3.2
Legislationfor
Marine
NOx
Reduction
InadditiontohavingtomeetthefuelsulfurlimitsinTable1,shipsoperatingintheECAsmustmeettheMARPOLAnnexVIMarineTierIIINOxlimitsin2016.
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Table 2 (Ref. 9) shows the applicable NOx limits for ships and the dates that they
becameorwillbecomeeffective.
Table2. MARPOLAnnexVINOxEmissionLimits(Source:Ref.9)
Tier Date
NOxLimit,g/kWh
n
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3.3 CompliancewithMarineSOxandNOxLegislation
Given theproliferationof theECAsand thepossibility thatmoreECAs,suchas in theMediterraneanSeaandthecoastofMexico,maycomeintobeinginthefuture,thereis
astrongincentiveforshipownersandoperatorstoexploretheuseofalternativefuelstosatisfythelowerfuelsulfurandNOxlimits.
AnotherapproachformeetingtheNOxandSOx limits istoinstallemissionscompliantenginesorSCRequipmentforNOxreductionandexhaustaftertreatmentdevicesknownasscrubbers forSOxreduction.When lookingatthese technologies,thecosttradeofffortheirinstallation,operation,andmaintenanceversusthecostofthealternativefuelmustbeconsidered.
This report deals only with fuels that are suitable for heavyduty diesel enginesproviding propulsion and auxiliary energy on commercial ships, which is the bulk ofmarinefuelconsumption.
Turbine engines are rarely used on commercial ships. Part of the reason is that gasturbinesaregenerallycostlyandlessefficientthandieselenginesandthereforearelesssuitedforcommercialuse.Thesamegoesforsparkignition(SI)engines.Steamturbinesare extremely fuel flexible but are also slow starting. Furthermore, they require arathersteadyloadinthehighband,whichiswhytheyarenotcommon.
Otherfuelsnotincludedforpractical,economical,orsafetyrelatedlimitationsofshipsarethefollowing:
Nuclearfuelso Thoriumo Uraniumo Plutoniumo H3
Windorsolarpowero Sailso Kiteso Windturbineso Photovoltaiccells
Solidboilerfuelso Coalo Cokeo Peato Lignite
GasturbineorSIenginespecificfuelso Keroseneo Ethanolo Gasoline
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Gasificationfuelso Woodandothercellulosicbiomasso Sludgeandotherorganicwastes
Electrochemicalfuelso Hydrogeno Batteries
Adistinctionshouldbemadebetweendropinfuelsasdefined inSection5,whichcanbe distributed through existing channels, and non dropinfuels, which require acompletely new infrastructure. Marine fuels in particular should be availableeverywhere in the world. For this reason, particularly rare and exotic fuels are notincludedinthisdiscussionoffuturemarinefuels.
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4. FuelPricesandAvailability
Thissectionexaminesthecostandavailabilityofmarinefuels.
4.1 CurrentMarineFuels(WorldMarket)
Thereissomeuncertaintyastoglobalmarinefuelconsumption.Thevariationbetweenstudies suggests a possible range between 279400MT/year. On thebasis of severalstudies,IMOestimatesthetotal2007fuelconsumptionat333MT/year(Figure5).
Figure5.
Global
Marine
Fuel
Consumption
Estimates,
IMO
2009
(Source:Ref.11)
MarinefuelstandardsaresetinISO(InternationalStandardsOrganization)8217.Thereare10gradesofresidualfuelofwhich380and180arethemostcommon.
TheIMOestimatesthat77%ofallmarinefuel(257MT/year) isresidualfueloil(RFO).HighsulfurRFOuseisconcentratedonthelargestlonghaulvessels(Ref.10).
Figure 6 shows a typical fuel mix sold in Singapore one of the worlds busiestseaports.
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Figure6. TypicalHeavyMarineFuelTypeDistribution
(Source:SingaporePortBunkeringStatistics2009,
http://www.mpa.gov.sg/sites/port_and_shipping/port/bunkering/
bunkering_statistics/bunker_sales_volume_in_port.page)
BecausetheSingaporePortsellspracticallynoMGOormarinedieseloil(MDO), itwill
beassumedthatthedistributionisvalidforheavyfuelsonly(i.e.,77.2%ofthemarket).
Distillate fuelswill thusaddup to22.8%.The resulting fuelstatistics, including lighter
fueltypesnotsoldinSingapore,areshowninTable3.
Table3. GlobalMarineFuelUseEstimatedfromIMOandSingaporePortBunkering
Statistics2009
FuelType OtherNames
MarketPercent
(%)
Megatons
perYear
Heavyfuel500CSt HSFO500CSt,RFO,RMG 500a,
IFO500,MFO500 10 33
Heavyfuel380CSt HSFO380CSt,RFO,RMG 380,
IFO380,MFO380 60 200
Heavyfuel180CSt HSFO180CSt,RFO,RMG 180,
IFO180,MFO180 6 20
Distillatefuels
Diesel,
Marine
diesel,
MGO,
MDO,LFO 23 77
Others 1 3
Total 100 333a RMG=residualmarinegas;IFO=intermediatefueloil.
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4.2 GlobalFuelConsumptionbyVesselType
TheIMOestimatesthetotalworldfleetasof2007tobe100,243vesselsabove100GT
(Ref.11). The fleet consists of approximately 40% cargo ships, 20% tankers, and 25%
containerships,
according
to
Det
Norske
Veritas
(DNV)
(Ref.
12);
see
Figures
7and
8.
Figure7. TheTotalWorldMarineFleetAccordingtoIMO(Source:Ref.11).
Only25%of thevessels runonRFO;however, theyaccount for77%ofglobalmarine
fuelconsumption.
Figure8. WorldBunkerFuelDemand(Source:Ref.10)
Service,passenger,
fishing
Cargoships
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4.3 FuelCost
Highviscosity, highsulfur fuel oil (HSFO) is the least costly fuel, whereas prices forlighter fuels with less sulfur generally have higher costs. The baseline for HSF380 is
about $700 USD/ton. Marine diesel MDO (or MGO) fuels are about $1,000 USD/ton.Figure9showsindexpricesfromBunkerworld.
Figure9. BunkerworldIndexPricesofHFSO380(top)andMDO(bottom)
(Source:Ref37)
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Theoncostsofdifferentlightfuelsaresomewherebetween$100and$400USD/ton,asshowninFigure10.Thedifferencevarieswithtime.
Figure10. CostofLighterLowSulphurFuelsCompared
toHighSulphurBunkerFuel(Purvin&Gertz)(Source:Ref.10)
World LNG prices are in the range of 0.05 EUR/kWh, which corresponds to about$1,000USD/ton, which is comparable to light fuel (MGO or MDO). However, LNGtypically holds 2025% more energy per ton compared to MDO, so the price isattractive.
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Thispageintentionallyblank.
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5. AlternativeMarineFuelIncentives
Currently,thereareanumberofincentivesforusingalternativefuels.Theseincludethe
following:
TheMARPOLAnnexVISOxandNOxlegislationdiscussedinSection2. Thepricefluctuationsoffossilfuels. ThepredictionofadieselfuelshortageinEurope(Ref.13). Possible scarcity of lowersulfur distillate fuel in 2015 when the switch from
1.0%to0.1%sulfurrequirementtakeseffect(Ref.2).
CurrentECAswiththeirSOxandNOxlimits. TheproliferationofECAs,withthepossibilitythatfutureECAsmaycome into
force in the Mediterranean Sea and off the coasts of Mexico and Singapore(whichhas,infact,requestedanECA).
In the United States, the Renewable Fuels Standard (RFS), which requires acertainamountofrenewablefuelsaspartoftheavailablefuelinventory.
The introductionby IMO inMARPOLAnnexVIoftheEnergyEfficiencyDesignIndex (EEDI), which would make mandatory some measures to reduceemissions of GHGs, such as CO2 from international shipping. The EEDIstandardsphasein from2013to2025.TheEEDIcreatesacommonmetrictomeasureandimprovenewshipefficiency.ThismetriciscalculatedastherateofCO2emissionsfromaship.
Alternative fuels that can help satisfy the above requirements and having certainattributes can possibly be substituted for the fossil fuels currently in use. Thesealternativefuelsneedtohavethefollowingcharacteristics:
Ideally,thefuelsshouldnothaveamajorimpactontheengineandshipboardfuelsystemssuchthatthesesystemsmustbeextensivelymodifiedorreplaced.
No degradation of engine performance occurs with their use that wouldrequireenginereplacementorextensivemodification.
ThefuelslowertheengineSOxandNOxemissions. The fuels are competitively priced with the current Heavy Residual Fuel Oil
priceofapproximately$700(USD)/ton(Ref.14).
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The alternative fuels are available in sufficient quantities worldwide orregionallyforbunkering.
Thefuelscanbemixedwithcurrentfossilfuels. Thefuelsaresafetouseanddonotpresentanymajorenvironmentalrisks.
Afuelsatisfyingtheserequirementsiscalledadropinfuel.
In addition to regulatory and monetary incentives for alternative fuels, the TransEuropean Transport Network Executive Agency has taken action through its2011EU92079S Project to identify and minimize the barriers when building andoperatinganLNGfueledvessel(Ref.15).
Theprojectwasselectedforfundingunderthe2011TENT(TransEuropeanTransportNetwork) Annual Call, and will examine the technical requirements, regulations, andenvironmentaloperationpermitsthatneedtobemetinordertoshiftfromtraditionallyfueledenginestoLNG.LNGisrapidlyemergingasacheaperandmoreenvironmentallyfriendly fuel for the maritime sector, and its uptake is encouraged by the EuropeanUnion.
Specificaspects related to themanufacturing,conversion,certification,andoperation
phasesofanLNGfueledvesselwillbeanalyzed.Theseresultswillbeexchangedwithother ongoing LNGrelated projects, as well as with the European Maritime SafetyAgency.Theprojectwillbe implemented inapartnershipwithstakeholdersconsistingof shipowners, cargo owners, LNG suppliers, ports, and marine equipmentmanufacturers. Among participating shipowners will be Viking Line, operator of the2,800passenger,dualfuelcruiseferrytheVikingGrace.
The project will receive 1.2 million in funding from the European Union under theTENTprogram.Thiscontributionconstitutes50%oftheoverallbudget.
The projectwill be managed by the TransEuropean Transport Network ExecutiveAgencyandissettobecompletedbytheendof2014(Ref.16).
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6. AlternativeMarineFuelsandEngines
Currently,thereareliquidfossilfuels, liquidbiofuels,andgaseousfuelsthatare inuse
orcanbeusedbyshipsforcompliancewiththeexistingandforthcomingenvironmentalairpollutionrequirements.
The feedstocks for current and future marine fuels are shown in Table 4. Of these;biodiesel(FAME),methanol,algae,andHDRDareconsideredviablealternativemarinefuelsandarediscussedindetailinSection6.3.
Table4. FeedstocksandDerivedFuels
Feedstock
Naturalgas,biogas
CrudeoilVegetableoils,
animalfats,algaelipids
Biomass
Fuels
CNG,LNG IFO,
LSFO,
LPG,
MGO
Biodiesel(FAME),
HDRD(secondgenerationbiodiesel)
BTL,
a
GTL,
methanol,
DME,pyrolysisoil,LBG
a CNG=compressednaturalgas;BTL=biomasstoliquid;GTL=gastoliquid;DME=dimethyl
ether;andLBG=liquefiedbiogas.
Thereare liquidbiofuelsand fossil fuels thatare low insulfurandcansatisfy the fuelsulfurrequirementsoftheECAsandMARPOLAnnexVI.Inlieuofusinglowsulfurfuels,anotheroptionistousescrubbersfittedintheengineexhausttoremovetheSOx.
TheEffshipProjectinvestigatesmethanolanddimethylether(DME)asalternativefuelsinWorkPackage2(Ref.17).ThefueloptionsmentionedareLNG,methanol,DME,andgastoliquids(GTL)formulations.However,noconclusionhasyetbeenreached.
MANDiesel&Turboselectronicallycontrolled,gasinjected,lowspeedmainenginegasinjection (MEGI) engine types are available in dualfuel versions with the LPGfueledversion designated MELGI (Ref. 18). The liquid MEGI engines performance isequivalent intermsofoutput,efficiency,andrpmtoMANDiesel&TurbosMECand
MEBseriesofengines.AstheliquidMEGIenginesfuelsystemhasfewmovingparts,itisalsomoretolerantofdifferentfueltypesandaccordinglycanrunonDME.Itcanburngasorfueloilatanyratiodependingonthefuelaboardandtherelativefuelcost,anditoperateswithnomethaneslip.
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DualfuelsystemsareavailablebothformethanolandLPG(propanedualfuel[Ref.19]).
6.1 LiquidorCrudeBasedFossilFuels(IFO,LSFO,MGO,
andMSAR2
Bunker
Oil)
Accordingtothe IMO(Ref.20),about77%oftotalmarinefuelsusedonaglobalbasisare residual fuels (e.g., IFOs). LSFOs and MGOs are used as secondary fuels forcompliancewithECAandSECArestrictions.
Along with global warming, potential sulfur content remains the main concern withconventionalmarinefuels.Thesulfurcontentisgenerallyhighcomparedtoroadfuels,as shown inFigure11. According to DNV, the totalSO2 emission from ships is about130kilotonsperyear.
Figure11. SulfurContentofConventionalMarineFuels(Source:Ref.4)
The emissions of both sulfur and other pollutants can also be reduced effectively byboosting the efficiency of the propulsion system. It is worth mentioning that marinetransportonlargecontainershipsonlyrequires2to3gramsoffuelperton*km(MaerskLineaverage).Roadtransportbytruckrequiresabout15g/ton*km(globalaverage).
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Someconventionalmeansofefficiencyboostingmaybeveryeffective.Forinstance,theanticipatedMrskTripleEshipsoffer50%CO2reductionbymeansofa16%increaseincontainer capacity, a 19% reduction in engine power, and a design speed that is2knotslower(Ref.21).
Existing ships such as the Emma Maersk have turbocompounding and othertechnologiestoincreasetotalefficiency.
Fossil fuels that are available for marine use are ultralow sulfur diesel (ULSD) fuel,which isthetermusedtodescribedieselfuelswithsubstantially lowersulfurcontent,andlowsulfurresidualfuel(LSRF).ForULSDtheamountofsulfurcanvaryfromcountryto country. For example in the United States and Canada it is 15 ppm and in othercountriesitcanbeaslowas10ppmandhighas50ppm.Notallcountriesrequirethat
marinedieselbeULSDbutintheUSandCanadaULSDisrequiredformarinedieselfuelaswellasovertheroadandoffroaddieselpoweredvehicles.Asof2006,almostallofthe petroleumbased diesel fuel available in Europe and North America is of a ULSDtype.
LSRF isanother fossil fuelthatcansatisfythecurrentrequirements for low fuelsulfurcontent.LSRFcanbeproducedby(1)therefineryprocessesthatremovesulfurfromtheoil (hydrodesulphurization), (2)theblendingofhighsulfurresidualoilswith lowsulfurdistillateoils,or(3)acombinationofthesemethods.
Itisconceivablethatthesefuelswillsufficeforthemarineindustryforlowsulfurfuelsuntil2016whentheNOxrequirementsareeffective.Atthistime,theuseofthesefuelswill require the installation of NOx aftertreatment devices such as SCR, EGR, or theinstallationofemissionscomplaintenginestosatisfytheNOxlimitswithintheECAs.
Itispossiblethatconventionalfossilbasedfuelswillremainthefuelofchoiceforalongtime. In different scenarios, the IMO projects a rather low penetration of alternativefuels,rangingfrom510%(tankshipstocoastwise,respectively)in2020toamaximum
2050% (tankships tocoastwise, respectively) in2050 (Ref.20).Thus, fossil fuelsarepredictedtobepredominantintheforeseeablefuture.
Maersk successfully tested a lowcost alternative to heavy fuel oil called MSAR2(MulPhaseSuperfineAtomizedResidue)bunkeroilusinga2strokemarinedieselengineofaMaerskLinecontainership,anenginefairlytypicalofatypetobefoundonmodernships.Thetestswerecarriedoutinlate2012.
Quadrise,theinnovatorsofthisMarineMSAR2bunkeroil,anticipatethatcommercial
volumeswillbeproducedprogressivelyfrommid2013,withafullcommercialrolloutthefollowingyear.
Quadrisewas formed inthe1990sbyagroupofformerBPspecialistswhodevelopednewtechnologytoproduceMSARfromavarietyofheavyhydrocarbonswithsuperior
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combustion characteristics. In 2004, a longterm alliance agreement was establishedwithAkzoNobel,aworldleaderinsurfacechemistry.
MSARFuelTechnologyrendersheavyhydrocarbonseasiertousebyproducingalow
viscosityfueloilusingwaterinsteadofexpensiveoilbaseddiluents,andalsoproducesasuperiorfuelwithenhancedcombustionfeatures.
The process involves injecting smaller fuel droplets in a stable waterbased emulsionintothecylinder,resultinginacompletecombustionthatproduceslowerNOxandPMexhaustgasemissions.
Besidesthelowcostbenefitsitofferstoshipownersasaheavyoilbunkerfuel,thenewtechnologyhelpsoilrefinersasitfreesupvaluabledistillatestraditionallyusedforHFO
manufacture, providing a viable alternative process for handling the bottom of thecrudeoilbarrelwithoutsignificantexpenditureandresultinginincreasedprofitability.
TheMSARprocesstransformshydrocarbonsthataresolidatroomtemperatures(andhavetobeheatedtotemperaturesover100Cinordertoflow)intoaproductthatcan,dependingonclientrequirements,bestoredandtransportedatambienttemperaturesof1530C.Asaresult,theenergyrequirementsforhandlingandtransportingMSARare lower than thoseofHFO,which isgenerallyhandledat temperatures inexcessof50C.
MSAR fuel can be handled using the same equipment and vessels used forconventionalHFO.OperatingproceduresandcontingencyplansdevelopedforHFOaregenerallysuitable,andwherenecessaryadapted,forMSARpurposes(Ref.22).
6.2 LiquidBiofuels(FuelsfromVegetableOilsandAnimal
Fats,Straight,Hydrogenated,orEsterified)
Liquid biofuels available for marine use are biodiesel, FAME, algae fuels, methanol,hydrogenationderived renewable diesel (HDRD), which is also known as secondgenerationbiodiesel,andpyrolysisoil.
SoybeanoilhasbeenusedbytheMolsLinien(Ferryline)inDenmark.Fishandchickenoilshavealsobeentested.
Thepotentialforoilsandfatshasbeenexploitedbytheautomotivesectorforyears,soit isquestionablehowmuchpotentialactually remains.Drawbacksof these fuelsare
limitedmiscibilitywithIFOfuel,sensitivitytofrost,andtheproblemofconservation.
Biodiesel(FAME),algaefuel,methanol,HDRD,andpyrolysisoilarevirtuallysulfurfree.The algae and HDRD fuels are compatible with diesel engines and their associatedshipboardfuelsystems.Biodiesel(FAME)isnotcompatiblewithcertainnonmetallicand
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metallicmaterialsandusually requiresmodificationofcurrentenginesand shipboardfuelsystems.Pyrolysisoilishighinacidity,hasalowcetanenumber,ispracticallysulfurfree,andisnotmixablewithdieselfuelsomustbemodifiedformarineuse(Ref.23).
FAMEisawellknownandprovenblendingcomponentforroadbaseddieselmachinesbuthasnotfounditswayintouseasamarinefuel.
Within the ISO 8217 framework, FAME is currently being adapted as a blendingcomponent forheavymarine fuel. It is foreseen thatavolumeconcentrationofup to7%willbeallowedinthenearfuture.
Fattyacidmethylestersarearefinedversionofvegetableoilsoranimalfats.TheyarecommoninroadtransportandwerealsousedinDenmarkbyM/FBittenClausenuntil
March2011.Theprojectwassuccessfulwithablendof25%animalbasedFAME.
FAME ingeneraldoesnotcauseanyproblems intheengine itself.Longtermstorage,however,canbeproblematic.Tankpaintandenginegaskets,hoses,nonmetallic,andsomemetallicfuelwettedpartsmayneedtobeadaptedtoFAME.
ThemainproblemwithFAME issustainabilitybecauseFAMEproductionreliesheavilyonpalmoilproduction,which isoften inconflictwiththepreservationofnaturalrainforests.Therefore,FAMEisgenerallynotseenasaviablelongtermoption.
In addition to the sustainability problem, the use of FAME in some U.S. marineapplicationshasnotbeensuccessful.TheU.S.NavyprohibitstheuseofFAMEbiodieselgiventhattheNavyuseswatertodisplacethefuelinitsshipboardtanksforballastandhascentrifugalpurifiersonboardtoseparatethefuelandwater.FAMEcausesahugeemulsionanddoesnotallowthefueltobeseparatedfromthewater.FAMEiscorrosivetometalsurfacesonceitmixeswithwaterandthemixturefallsout.TheUnitedStatesCoastGuardhadmicrobialgrowthproblemsononeofitscuttersinDuluth,Minnesota,when it lifteda2%blendofFAMEbiodiesel.Theproblemprevented thevessel from
sailing.ThetankshadtobeemptiedandcleanedandthevesselhadtoberefueledwithFAMEfreedieselfuel.Thecutternowprocuresthefuelbeforethemandatoryblendtoavoidfuelqualityissues(Ref.24).
6.2.1 Methanol
Methanol as a general fuel has been recommended by CEESA, an interdisciplinaryresearch cooperation fromDenmark. The reason is thatbiomasstomethanol/DME is
foreseen to be the most energyefficient pathway to procuring transport energy by2050.
ConversionsofmarinevesselstomethanolaresignificantlylesscostlythanconversionstoLNGbecauseofthesimplicityofthestoragesystemformethanol.Althoughmethanol
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itselfisslightlymorecostlythanLNG,thetradeoffbetweenmethanolandLNGinvolves
thecomplexityofthefuelsystemversusthecostofthefuel.
Methanol increasestheriskofcorrosion,whichmustbemetwithsufficientupgrading
offuel
tanks,
etc.,
and
the
low
energy
content
per
cubic
meter
(m
3
)of
methanol
means
thatittakesupcargospaceontheship.
Methanolhaspropertiesthataresimilartothoseofmethanewhenitisinjectedintoan
engine.Itcanbeusedinadualfuelconcept,asproposedbyWrtsil(Figure12).
Figure12. WrtsilDirectInjectionDualFuelConcept
forMethanolinLargeFourStrokeEngines
6.2.2 Biocrude(PyrolysisOil)
Biocrude,suchastheGermanbioliqSynCrude,isanintermediarypyrolysisoilproduced
from, forexample,theCatLiqTM
process.The feedstockcanbeeithersolidbiomassor
sludge. Like fossil crude, biocrude can also be refined into gasoline or diesellike
products. However, biocrude in its initial form is perhaps the cheapest liquid biofuel
possible.
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Themainchallengesareits:
Lowcetanenumber Highwatercontent Poorlubricity
However,theuseofbiocrudeasafeasiblemarinefuelisyettobeproven.
6.3 GaseousFuels
Gaseous fuelsavailable formarineusearenaturalgasandpropane (i.e., LPG).ThesefuelsarenotonlyverylowinsulfurcontentbuttheyalsocombustsuchthatNOx,PM,
and CO2 are reduced. Natural gas can be carried in a compressed state calledcompressednaturalgas(CNG)orinaliquidstatecalledliquefiednaturalgas(LNG).
PropaneorLPG ismentionedfromtimetotimeasapotentialmarinefuelscandidate.However,thereseemstobeverylimitedmaterialavailableonLPGsviabilityasamarinefuel.ThegeneralviewaroundtheglobeseemstobethatLPGisapremiumproductand,assuch, ispricedaccordinglyand is tooexpensivecompared tootheralternative fueloptions. So, although the supply is there, its current markets are in automotivetransportationanddomesticheatingandcooking,markets thathaveadifferentprice
referencethanshipping.
In terms of safety, propane is heavier than air and thus presents an explosive safetyhazard if itweretoaccumulate inthebilgesor lowsectionsofashipsengineroom intheeventofaleakinthefuelsystem;thus,itisnotconsideredsafeforshipboarduse.
CNG ismadebycompressingnaturalgas to less than1%of thevolume itoccupiesatstandardatmosphericpressure.Itisstoredanddistributedincontainersatapressureof200248bar(29003600psi),usuallyincylindricalorsphericalshapes.
LNG achieves a higher reduction in volume than CNG. The liquefaction processcondensesthenaturalgasintoaliquidatclosetoatmosphericpressurebycoolingittoapproximately162C(260F).TheenergydensityofLNG is2.4timesthatofCNGor60% of that of diesel fuel. This makes LNG attractive for use in marine applicationswherestoragespaceandendurancearecritical.
The natural gas for CNG and LNG can also be derived from renewable biogas and issometimescalledbiomethane.
LNGisoneofthemostpromisingalternativemarinefuels.Ittakesupabout1/600thofthevolumeofnaturalgasinthegaseousstate.Hazardsincludeitsflammabilityandlowfreezing temperature (163C (260F), such that marine regulations require extrasafetyprecautionslikedoublewallpiping,gasdetectionssystems,etc.,inenginerooms.
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NorwayalreadyhasanestablishedLNGinfrastructure(forshortseashipping).Inthefallof2011,26LNGshipswerereportedinoperationinNorway(Ref.25),ofwhich15wereferries.Another15LNGshipsareunderconstruction.InPoland,twodualfuelLNGshipsarebeingbuiltfortheferrycompanyFjordline.
It issometimessuggestedthatabouthalfthecommercialfleetofmarinevesselscouldbe converted to LNG. However, these would not be the largest vessels, because therange would probably not satisfy oceangoing ships. Thus, in terms of amount ofconvertedfueluse,thepercentagewouldbemuchlowerthanhalfthefleet.Ithasbeenestimated that there will be a consumption of2.4MT of LNG in 2020 (Ref. 26). Thisprojectedamountcorrespondstolessthan1%ofglobalshipping.
Foreconomicreasons,LNGconversionsgenerallyrequirethat3040%oftheoperation
is located within ECA areas. Otherwise, the capital investment will be too heavy(Ref.19).
A major concern with LNG is the possibility for debunkering (or emptying the fueltanks).Thisstep isnecessarywhenaship istobeanchoredforanextendedperiodoftime.UnlessspecialLNGdebunkeringfacilitiesareavailableintheport,thegaswouldboil off, causing huge methane losses to the atmosphere. In case of groundingaccidents, a technique fordebunkering would also be necessary. Another concern ispressure increasewhenconsumptionoccursbelowthenaturalboiloffrate,whichwill
happen ifthere isnoreliquefactionplanavailableonboard.Reliquefactionofboiloffgasrequiresabout0.8kWh/kggas.OnelargeLNGcarrier,suchasQatarQmax,requires56MWofreliquefactionpower,correspondingtoaboiloffrateof8tons/hour.
Athirdconcerntobeaddressedismethaneslipfromlargermarineenginesburninggas.Methane slip will be present, especially on fourstroke, dualfuel engines (Figure13),partlyfromthescavengingprocessinthecylinderandpartlyfromtheventilationfromthe crank case, which is being led to the atmosphere. In addition, there is someuncertaintyastowhetherfutureregulationswillallowLNGtankstobesituateddirectly
below the outfitting/accommodation of the ship. If not, this constraint could causedifficultiesinretrofittingcertainships.
LNG is chemically identical to biomethane. Biomethane is generally known to be themostCO2friendlyfuelofall(Ref.27).RecentactivitiesintheareabelongtotheHollandInnovationTeamandAngloDutchBioLNG;see(Ref.28).
Biogasrequiresdualfueltechnologyforthemarineengineandextrastoragefacilities,either as pressure tanks or cryogenic tanks for LBG. Biogas is usually produced from
inland biowaste and thus presents challenges in terms of costs to transport LBG tomarinevessels.
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Figure13. WrtsilPortInjectionDualFuelConcept
forGasUseinLargeFourStrokeEngines
6.4 ExhaustGasTreatmentSystems(EGTSs)
AnalternativetousinglowsulfurfuelsforreducingtheSOxemittedintheexhaustisto
clean theexhaustgasusingscrubber technology.This technology isproven foruseat
shoresidepowerstationsworldwide.Thesesystemscanclean theexhaust to theSOx
levelthat isequivalenttotherequiredfuelsulfurcontent.UsingaSOxscrubberoffers
shippers the flexibility of using either a lowsulfur fuel or highersulfur fuel. The
scrubbingefficienciesofSOxscrubberspresentedin(Ref.8)areasfollows:
PMtrappinggreaterthan80% SOxremovalgreaterthan98%
SOxscrubbersareclassifiedaswetordry,asfollows:
Wetsystemuseswater(seawaterorfresh)asthescrubbingmedium Drysystemusesadrychemical,suchascalciumhydroxide.
Wetsystems
are
further
divided
into
the
following:
Openloopsystemsthatuseseawater.
Port Gas Injectors
Diesel main injector
Diesel pilot injector
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Closedloop systems that use freshwater with the addition of an alkalinechemical.
Hybridsystemsthatcanoperateinbothopenloopandclosedloopmodes.Foracomparisonofthesystems,seeSection6.8andTable3oftheLloydsRegister(LR)publication,UnderstandingExhaustGasTreatmentSystems,GuidanceforShipownersandOperators, from Juneof2012 (Ref.29).ThispublicationalsoprovidesadetaileddiscussionofSOx scrubbingandNOxabatement systems,aswellas twocase studiesperformedontwoferries,thePrideofKentandtheFicariaSeaways.
Basedona2009planusingaSOxexhaustscrubberthatwasinstalledonaDetForenedeDampskibsSelskab(DFDS)passengercarferry,itwasestimatedthatthepaybackperiod
couldbeaslowastwoyears.Theplanistooperatethescrubberinthehighlyefficientsodiumhydroxide(NaOH)modeincoastalwatersandinthesaltwatermodeintheopenseawherealowersulfurscrubbingefficiencyissufficient(Ref.8).
OnlyafewshipsareoperatingwithSOxscrubbersorhaveorderedthem,andmanyofthese are on a trial basis. Royal Caribbean Cruise Lines has contracted with WrtsilHamworthyfortheinstallationoffourhybridscrubbersforitstwonewSunshineclassvesselsafteranearlierpilotinstallationaboarditsLibertyoftheSeas.Thefirstvesselisduetoreceivedeliveryinautumn2014,andthesecondinthespringof2015(Ref.30).
ExhaustgasSOxscrubbersbyGreenTechMarine (GTMR15Scrubber)were recentlyinstalled by Norwegian Cruise Lines (NCL) in their Pride of America. The scrubberswereinstalledinMarch2013duringtheshipsdrydocking.Thesmallfootprintandlowweightof theGreenTechsystem iscompact,and thusnopassengerorcrewspace islost,theinstallationneedsnosteelworkmodification,andthescrubbertakesupaboutthesameamountofspaceastheexhaustsilenceritreplaces.Thesystemcanoperateinclosedoropenmode(Ref.31).KoreasSTXOffshore&ShipbuildingawardedWrtsilacontracttosupplyexhaustgascleaningsystemsforfournewcontainerrollon,rolloff(RO/RO, or ConRo) vessels being built for Italys Ignazio Messina & Co. The Wrtsil
systems tobesuppliedwillcleanbothSOxandparticulatematteremissions from themainengines,auxiliaryengines,and theboiler.Deliveriesarescheduled to takeplaceduring2013and2014,and thevesselsare tobedeliveredby the shipyard to IgnazioMessina & Co during the second half of 2014 (Ref.32). Great Lakes Seaway shippingline,AlgomaCentralMarine, isbuildingsixnew225mlongEquinoxclass lakersthatwillbe45%morefuelefficientthanexistinglakers.TheywillbeequippedwithcompleteWrtsil propulsion packages that come with fully integrated, freshwater scrubbersystems(Ref.33).
Exhaust gas treatment systems for NOx, (NOx reducing devices) will provide theflexibility to operate ships built after January 1, 2016, in ECAs designated for NOxemissioncontrol.
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Tier IIINOx limitswillapply toallshipsconstructedonorafter January1,2016,withengines over130kW thatoperate insideanECANOxarea. Unlike the sulfur limits inRegulation14ofMARPOLAnnexVI,theTierIIINOxlimitswillnotretroactivelyapplytoships constructed before January1, 2016 (except in the case of additional or
nonidenticalreplacementenginesinstalledonorafterJanuary1,2016[Ref.29]).
For compliance with Tier II NOx emission limits, shippers can implement onengineadjustmentsandmodificationsthatwillbeabletosatisfythese limits.ForTier IIINOxcompliance,thecurrentthinkingisthateitherSCRorEGRtechnologieswillbenecessaryfor meeting the Tier III limits. For a detailed discussion of NOx emission reductiontechnologies, consult the Lloyds Register publication, Understanding Exhaust GasTreatment Systems, Guidance for Shipowners and Operators, from June of 2012 athttp://www.lr.org/eca(Ref.8).
Scrubbersystemsarepricedatabout$3millionUSD.ThepricedifferencebetweenHFO380andLSFOisroughly$40USD/ton,whereasthepricepremiumofMGOcomparedtoHFO380 isabout$330USD/ton.Thepaybackofscrubbersystemstypicallyreliesonapricedifferenceof$200600USD/ton.ScrubbersystemcostsareshowninFigure14.
Figure14. CostsofScrubberSystems[CoupleSystems,
AlfaLaval](seeRef.34forcostcalculations)
Theproblemswithscrubbershavetodowiththelossofcargocapacityduetothelargephysicalsizeofthesystems.Winteroperationcanalsobeachallenge(Ref.35).
SeeAppendixAforillustrationsandoperationaldetailsofsomeexhaustaftertreatment
systemsprovidedbyvariousvendors.
0
1
2
3
0 5 10 15 20 25
M
MW
Cost of scrubber system
MEUR
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Thispageintentionallyblank.
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7. AssessingAlternativeFuelsforMarineUse
When assessing fuels, it is necessary to evaluate several parameters related to the
technical,economic,andenvironmentalimplicationsoftheuseofeachfuel.
Theconsiderationshavebeengroupedintofivemaincriteriawithsubcriteria.
Engineandfuelsystemcost,includingo Newvesseloncosto Retrofitinvestmentso Increasedmaintenancecost
Projectedfuelcost,includingo Projectedfuelpricepermegajoule(MJ)o Availabilityandcostofinfrastructureo Longtermworldsupplyo Fuelconsumptionpenalty(e.g.,becauseoflesserefficiency,boiloff)
Emissionabatementcost,includingo PMportcompliance(e.g.,fuelchange)o SOxSECA(e.g.,scrubber)o NOxSECA(e.g.,SCR,EGR)o CO2EEDI(e.g.,slowsteaming,heatrecovery)
Safetyrelatedcost,includingo Approvals(classification)o Additionalinsurancecosto Crewtrainingandeducation
Indirectcost,includingo Reducedrangebetweenbunkeringo Reducedcargocapacityo Increasedwaitingtimeinports
The following paragraphs discuss the favorable attributes and drawbacks of thealternativemarinefuelswithregardtotheirpracticalityandaffordabilityformarineuse.
7.1 LiquidFossilFuels(ULSD,LSRF)Advantages
7.1.1 FuelSystemandEngineCompatibility
These fuelsarecurrently inuse inmanymarineengine installationsorcanbeused incurrentmarineenginesbecauseoftheirsimilaritytothefuelsthatareinusetoday.ThelighterULSDor lowsulfurdiesel (LSD) issimilar todistillatediesel fuel that isused inmedium and highspeed shipboard diesels and on ships burning residual fuel whenenteringa fuelsulfurrestrictionzone.Forshipsnormallyburningresidual fuel,special
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proceduresmustbeobservedwhentransitioningtothe lowerviscositydistillatefuels.The diesel engine manufacturers have developed a Smart Switch to facilitate thisoperation, and there are publications and bulletins available for switching to andoperatingonlowsulfurfuels.
Thesefuelsarecompatiblewithcurrentshipboarddieselenginesandfuelsystems.Forships that do not operate for a substantial amount of time in an ECA, theowners/operators may choose to use lowersulfur fuels only when transiting an ECA.Thisscenariorequirestheinstallationofadditionalfueltankswithassociatedpipingandpumpsforthelowsulfurfuel.
7.1.2 LowerSOxEmissions
ThelowersulfurlevelsinthesefuelsensurethattheshipwillbeincompliancewiththelowersulfurlimitsrequiredintheECAsandbytheIMO.
7.1.3 Safety
Thefuelsaresafetousehavingsimilarcharacteristicstocurrentdistillateandresidualdieselfuels.
7.1.4 Availability
They are commercially available for ship bunkering. Most of the ports that currentlyofferhighsulfurfueloilsalsohaveavailablethelowsulfurfueloilofthesamegrade.
7.2 LiquidFossilFuels(ULSD,LSRF)Drawbacks
7.2.1 Price
The cleaner, lowersulfur distillate and residual fuels are more expensive than thecurrent fuels. The lowsulfur residual fuels have a higher price than the highsulfurresidualfuelsbecauseofthecostofthedesulfurizationprocessandincreasingdemand.Theexistingpricedifference(basedonavailablepublicbunkerprices)betweendistillate(0.10.5%sulfur)andresidualfuel(2.03.5%sulfur)isabout$300USDmorepertonfordistillate.Basedonapreliminaryreporton lowsulfur (1%)marine fuels,thepremiumcostof the lowersulfurHFOcouldbeasmuchas$100USD/metric ton (Ref.36).Thepricesof marine fuels at twoEuropeanports in July 2012are summarized inTable5(Ref.37).
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Table5shows that the lowersulfur fuelsaremoreexpensive than theheavyresidualfuels.Thedistillatefuels(lowsulfurMGO[LSMGO]andMDO)havepricepremiumswellabovethoseoftheresidualfuels.
Table5. MarineFuelPricesinJuly2012inUSD/MetricTon(MT)byPort
Port
HighSulfur
HeavyFuel
(IF380)
LowSulfur
HeavyFuel
(LS380)
(1%S)
HighSulfur
HeavyFuel
(IF180)
LowSulfur
HeavyFuel
(LS180)
(1%S)
LSMGO
(0.1%S) MDO
Copenhagen $597.50 $658.50 $630.00 $683.50 $907.50 $865.50
Rotterdam $580.00 $631.50 $602.00 $653.00 $865.00
7.2.2 Characteristics
Thecleaner fuels,especially ifdistillate isused,havedifferentcharacteristics, suchaslowerviscosity,thatcancausefuelsystemandengineoperationproblems.Theenginescanoperatesatisfactorilyonthelowerviscosityandlowersulfurfuelswhentheproperchangeover precautions are followed. When switching from a heavy fuel to distillatefuel, therecouldbe incompatibilityproblems that result in filterclogging; inaddition,theproperbasenumber(BN)lubeoilmustbemaintainedwhenoperatingonthehighor lowsulfurfuel,andtheviscositymustbemaintainedattheproper leveltopreventfuelpumpdamage.ThefuelsystemmodificationsnecessaryforoperationonbothHFOandthe lowsulfurdistillateaddcomplexitytothealreadycomplex fuelsystem.Therearealsomodificationsrequiredtothe lubeoilsystemsothattheproperBN lubeoil isused, depending on the fuels sulfur level, to avoid engine damage. MAN B&W haspublishedadetailedmanualtitledOperationonLowSulfurFuels(Ref.8)thatexplainsthestepsthatshouldbetakenfordesigningormodifyinganexistingHFOfueloilsystemfor operation on lowsulfur fuels. When California enacted the lowsulfur fuelsrequirement forships inCaliforniaCoastalWaters (CCW),shipsexperiencedproblemswithenginestallingandlossofpropulsionwhenshiftingfromresidualtodistillatefuel.
7.2.3 FutureAvailability
There isaconcernthatwhenthe0.1%ECAfuelsulfur limittakeseffect in2015,therecouldbeaEuropeanshortageofMGO.Europe iscurrently inanetshortageofmiddle
distillates
and
has
to
import
them
(Ref.
38).
Thus,
there
could
be
a
supply
challenge
in
2015.
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7.3 LiquidBiofuelsCharacteristics
7.3.1 Biodiesel(FAME)Advantages
Fuel System and Engine CompatibilityMany marineengine manufacturershavecertifiedtheirengines foroperationonbiodieselorablendofbiodieselanddiesel fuel.Theoriginalenginemanufacturershouldbeconsultedfortheamountofbiodiesel theirengines canburn (i.e.,B20, etc.).B20 represents afuel of 80% diesel fuel and 20% biodiesel. Likewise, B100 represents a fueltotallymadeuptotallywithbiodiesel.
Lower SOx Emissions Neat biodiesel contains almost no sulfur, so SOxexhaustemissionsarepracticallyzero.Blendingwithregulardiesel lowersthesulfurcontentproportionally.
SafetyBiodieselisassafeasdieselfuel.Ithasahigherflashpointthandiesel,is biodegradable, and degrades quickly in water. The flash point of B100 isapproximately300F(149C),comparedto120170F(4977C)forpetroleumdiesel.
AvailabilityBiodieseliscommerciallyavailableatpricescomparabletothoseofmarinedieselfuel.Forqualitycontrol,itisproducedtospecificationssetbytheAmericanSocietyforTestingandMaterials(ASTM)andtheEuropeanUnion(EU).Ithasbeenclassifiedasanadvancedbiofuel.
7.3.2 Biodiesel(FAME)Drawbacks
LowTemperatureOperationBiodieselhasahighcloudpointcomparedwithpetroleum diesel that can result in filter clogging and poor fuel flow at lowtemperatures(i.e.,32Fandlower).Thefeedstockusedforthemanufactureofthebiodieselhasastrong influenceon thecloudpoint.Additivescanalsobeusedtolowerthecloudpoint.
Fuel System and Engine Compatibility Biodiesel, especially in higherconcentrations,candissolvecertainnonmetallicmaterialssuchasseals,rubberhoses,andgaskets.Itcanalso interactwithcertainmetallicmaterials,suchascopperandbrass.Foranexistingship,thefuelsystemandenginesmayhavetobe modified by changing out susceptible parts with biodieselcompatiblecomponentsforsatisfactoryoperation.
Cleaning Effect Biodiesel especially in higher concentrations has asolvent/scrubbing action that cleans/removes deposits from the fuel system,
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resulting incloggedfuelfilters.Thefuelsystemshouldbethoroughlycleaned,removingalldepositsandresidualmoisturebeforeusingbiodieselortherewillbeinordinatehighuseoffuelfilters.
LongTerm Storage Stability Biodiesel can degrade over time, formingcontaminantsofperoxides,acids,andotherinsolubles.Ifbiodieselisstoredformorethantwomonths,thefuelshouldbecloselymonitoredandtestedtoseethatitremainswithinspecification.Anantioxidantcanalsobeused(Ref.39).
7.3.3 AlgaeFuelsAdvantages
Potential Algae can grow at amazing rates compared to farmland crops.These growth rates potentially translate to a very high biomass yield perhectare.However,muchresearchisstillneededtofullyutilizethepotentialofalgaefuel.
FuelSystemandEngineCompatibilityWhenhydrotreated,itisadropinfuelintermsofcompatibilitywiththefuelsystemandenginecomponents.Testingto date by the U.S.Navy has shown no adverse effects from using a50/50blendofalgaefuelandpetroleumdieselfuelonengineandfuelsystemcomponents.
LowerSOxEmissionsAlgaefuelcontainsalmostnosulfur,sotheSOxexhaustemissions are practically zero. Blending with regular diesel lowers the sulfurcontentproportionally.
SafetyAlgaefuelisassafeasdieselfuel. Performance Algae fuels have slightly lower heating values than those of
petroleumdieselandloweraromatics.Blendingwithpetroleumdieselnegates
thesedrawbacks so theblended fuelsperformancecompares favorablywithpetroleum diesel. Algae fuel is produced to a hydrotreated renewable diesel(HRD)76 specificationand,whenblendedwith50%petroleumdiesel,meetstherequirementsforpetroleumdieselF76.Table6showsthecomparisonofthe 50/50 blend with the petroleum F76 fuel and the F76 specification(Ref.40).
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Table6. Comparisonof50/50BlendofAlgaeandF76PetroleumFuel
withPetroleumF76
Characteristic
MILDTL16884L
Requirements
PetroleumF76
(Typical)
50/50Blend
(Actual)
AcidNumber(mgKOH/g) 0.30(max) 0.08
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7.3.4 AlgaeFuelDrawbacks
AvailabilityCommercialavailability is limited. The U.S.Navy is the primaryuseranddeveloperofthefuelformarineuse.TheNavysplansaretoreduce
petroleum fueluseasmuchaspossible intheir fleet.Ademonstrationof theGreen Strike Force took place in 2012 using a 5050 algae/petroleum fuelblend,andthereareplanstobesailingthegreenfleetby2016.
Cost The current cost isprohibitive forgeneral commercialuseother thanexperimentallyorforperformancebaseddemonstrations.
Performance The neat algae fuel has lower heating value and aromaticsthanthatofpetroleumdiesel;whenblendedwithregulardieselfuel,however,
thesedrawbacksarenegated.
7.3.5 HydrogenationDerivedRenewableDiesel(HDRD)Advantages
FuelSystemandEngineCompatibilityHDRD isproducedbyrefining fatsorvegetable oils in a process known as fatty acidstohydrocarbonhydrotreatment.Dieselproducedusingthisprocess iscalledrenewabledieseltodifferentiateitfrombiodiesel,whichisaproductofthetransesterficationof
animal fats and vegetable oils. Renewable diesel and biodiesel use similarfeedstocks but have different processing methods that create chemicallydifferentproducts.
HDRDhasan identicalchemicalstructurewithpetroleumbaseddieselas it isfreeofestercompoundsand,whenproducedfromanimalfatwastes,haslowcarbon intensity and is referred to as advanced renewable diesel. It has alower production cost because it uses existing hydrotreatment processequipment inapetroleum refinery. Ithasbetter lowtemperatureoperability
than biodiesel; thus, it can be used in colder climates without gelling orcloggingfuelfilters.
HDRD is similar to petroleum diesel fuel and is compatible with new andexistingdieselenginesandfuelsystems. It isproducedtomeetcurrentdieselfuelspecificationASTMD975.
LowerSOxEmissionsHDRDfuelcontainsalmostnosulfursotheSOxexhaustemissions are practically zero. Blending with regular diesel lowers the sulfur
contentproportionally.
SafetyHDRD fuelmeetsthedieselfuelspecificationand isassafeasdieselfuel.
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7.3.6 HDRDDrawbacks
Availability Current availability is limited. There are only a few companiesthathaveinvestedtoproducehydrogenationderivedrenewablediesel.
ConocoPhillips produces renewable diesel from vegetable oil and crude oil.Nestes plant in Porvoo, Finland, processes vegetable and animal fats intorenewable diesel. Neste also has plants in Singapore and Rotterdam for theproductionofHDRD.BrazilianPetrobrasusescoprocessingofvegetableoilstomakeHDRD.
CetaneEnergyLLC inCarlsbad,NewMexico,produces renewablediesel fromvegetableoilsandwastes.Accordingtothecompany,itstechnologycanwork
withawiderangeof feedstocks, includinganimal fatandalgaloils.UKbasedRenewableDieselEurope istheexclusiveagent inEurope forthestandalonerenewabledieseltechnologydevelopedbyCetaneEnergy.
Othercompaniesthathaveplanstoproduceorareproducingrenewabledieselfuel through hydrogenation include Nippon Oil in Japan, BP in Australia,SyntroleumandTysonFoodsintheUnitedStates(DynamicFuels),andUOPEniinItalyandtheUnitedStates(Ref.41).
7.4 GaseousFuels:NaturalGas(Compressed[CNG]or
Liquefied[LNG])
NaturalgasstoredasLNG isaviable futuremarine fuelmainly forshortseashipping.Stored in itscompressed formasCNG,however, it isnotconsideredviable foruseonlonger routesbecauseof its long fueling times,extra space requirements for the fueltanks,andthe limitedvolumesthatcanbecarriedthatresult ina limitedrange.Thus,otherthanforvesselsonshortvoyagesthathavesufficientturnaroundtimeforfueling,theCNGconcept isnotconsidered thebestoptionwhenusingnaturalgasasashipspropulsionfuel.
7.4.1 NaturalGasAdvantages
Availability With the new methods for extracting natural gas from shaleformationsusing thefrackingmethod, therateofdevelopmentofnewgas
fields
should
assure
an
abundant
supply
for
years.
In
the
past
couple
of
years,
the growing global surplus of natural gas has become increasingly apparent.WhilemuchofthefocusintheUnitedStateshasbeenontherecoveryofshalegas,thediscoveryofenormousgasreservesoverseasinareaslikeoffshoreEastAfricaandtheCaspianSeahasmadeitobviousthatfearsaboutscarcitywere
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notwell founded (Ref.42).Availability isgood inmostpartsof theworld towhichshipssailfrequently.
Cost Natural gas is expected to be cost competitive with residual anddistillatefuelsthrough2035.Currently,itis70%lessthanresidualfueland85%less than distillate fuel; furthermore, the Energy Information Administrationexpectsittoholdthispriceadvantagethrough2035(Ref.43).Figure15showsthispriceadvantagethatnaturalgasisprojectedtomaintainoverresidualanddistillatefuelsthrough2035.
Figure15. ProjectedPricesofMarineFuels(Ref.43)
Lower Exhaust Emissions The use of natural gas results in the followingreductionsofSOx,NOx,PM,andCO2fromengineexhaustemissions(Ref.44):
o Carbonemissionsbyapproximately25%o SOxbyalmost100%o NOxby85%o PMby95%ItshouldbenotedthatwhileemissionsofCO2,SOx,NOxandPMarereducedsignificantly through theuseofnaturalgasasa fuel, there isaconcernover
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methaneslip.MethaneslipwillbeincludedintheGHGpicture,andtherebylead tohighpenaltyon futureCO2 taxation,etc.Methane slipwillalwaysbepresentwiththeknowndualfueltechnologies(e.g.,Ottocycle).
ShipConstructionRulesRulesforthesafeconstructionofshipsusingnaturalgasbasednaturalfuelhavebeendevelopedandpublishedbytheclassificationsocieties. There are rules, for example, by Det Norske Veritas (DNV), LloydsRegister(LR),andothers.
AvailabilityofMarineGasEnginesGasburningordualfuelmarineenginesin both slow and mediumspeed configurations are available from enginemanufacturessuchasWrtsil,MANB&W,andRollsRoyce(BergenEngines).Wrtsildevelopedaslowspeed,dualfuelenginein1973formarineuseand
followedwithahighpressure, twostrokegasengine formarineuse in1986.Currently,Wrtsiloffersaseriesofdualfuel,mediumspeedmarineengines.MAN B&W offers a slowspeed marine gas engine, and Rolls Royce has amediumspeed marinegas engine that meets theTier IIINOx limits thatwillbecomeeffectivein2016.MitsubishiHeavyIndustries,Ltd.,plansacombustionengine that efficiently burns highpressure gas through direct injection. Theenginewillbemarketedtocustomersafteremissionslevelsandfueleconomyaretestedthroughatrialrunthatstartsinlate2013atMitsubishiHeavysKobeshipyard. It is intended for LNG carriers, large tankers, and containerships
(Ref.45).
ExperiencewithNaturalGasasMarineFuelAhistoryspanningmanyyearsofexperienceexistsduringwhichshipshavesafelyoperatedwithLNGas theprimaryfuel.Section8.2describestheoperationofshipswithnaturalgasasafuel.
7.4.2 NaturalGasDrawbacks
Not Compatible with Existing Engines and Fuel SystemsNaturalgas isnotcompatiblewithexisting liquid fuel systemsand requires themodificationofexisting engines and changes or additions to the existing shipboard fuelsystems,aswellasotherchanges forsafetyreasons.Table7 is fromareportprepared by M.J. Bradley for the American Clean Skies Foundation (ACSF)(Ref.46) and shows the costs associated with converting three vessels ofdifferentsizestoaccommodatenaturalgasservice.
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Table7. CostsAssociatedwithConvertingMarineVesselstoLNGOperation
Type
Size
(tons) Engines
Engine
Cost
FuelSystem
Cost
TOTAL
CONVERSION
COST
Tug 150 21,500HP $1.2million $6.0 million $7.2millionFerry 1,000 23,000HP $1.8million $9.0million $10.8millionGreatLakesBulkCarrier
19,000 25,000HP $4.0million $20million $24million
Incomparison, theconversionof theBitViking,a177meterlongchemicalproducttanker,torunonLNGwasestimatedtocostabout$10millionUSD.Up
to
75%
of
the
conversion
cost
was
covered
by
the
Norwegian
NOx
fund,
which
awarded$7millionUSDtowardtheproject(Ref.47).
NewShipConstructionPremiumThecostofbuildinganewshippoweredbynaturalgashasapremiumover the construction costofa conventional shipwithfossilfuel.Thereisacostincreaseforthegasenginesandanotherforthegaseous fuelsystemandassociatedLNGstorage tanks.AGermanischerLloyd(GL)studyin2009notedanadditionalinvestmentof25%overthatofthecostfor constructing a typical new container ship (Ref.48). According to a DNV
report,ifashipspendsmorethan30%ofitsoperatingtimeinanECA,thecostofgasfueledenginescanbejustified(Ref.43).
Increased Fuel Storage Space Increased fuel storage space is required tocarrythenecessaryvolumeofgas forendurancesimilartoashipusing liquidfossilfuel.AgivenweightofnaturalgasstoredasLNGtakesuponlyabout40%of thevolumeof the sameweightofnaturalgas storedasCNGat3,600psi.Because LNGoccupiesmuch less space thanCNG, it is thepreferred storagemethod.WhenstoredasLNG,however,thefueltakesuptwiceasmuchspace
asliquidfossilfuel,andifstoredasCNG,ittakesuptofivetimesasmuchspace(Ref.46).Table8showsthevolumeoftheonboardfuelstoragerequirementsforthreetypesofmarinevessels.
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Table8. FuelUsageandStorageVolumesforThreeTypesofVessels
Vessel
Fuel
Type HP
DailyFuel
Use(gal)
TypicalMinimum
OnboardFuel
Storage
VolumeofOnboard
FuelStorage
[days] [gal]
Dist.or
Residual
[ft3]
LNG
[ft3]
CNG
[ft3]
TowingTug
Distillate 3,000 1,417 14 20,000 2,674 4,830 12,178
100carFerry
Distillate 6,000 2,268 7 16,000 2,139 3,864 9,742
GreatLakesOreCarrier
Residual 10,000 6,934 21 145,000 19,385 38,183 96,264
Figure 16 from Reference46 shows the relative weights and volumes of themarinefuels.
Figure16.
Weights
and
Volumes
of
Marine
Fuels
IncreasedFuelingTimeStoredasCNG,itisnotconsideredviablebecauseoflongfuelingtimes,extraspacerequirementsforthefueltanks,andthelimitedvolume thatcanbecarried that results ina limited range.So,other than forvesselsonshortvoyages thathavesufficient turnaroundtime for fueling, theCNG concept isnot considered thebestoptionwhenusingnaturalgas forashipspropulsionfuel.
IncreasedSafetyRequirementsThecarriageofnaturalgasasa fuelentailsadditional safety requirements over fossil fuels and results in constructionfeatures that are reflected in the higher construction cost. (See New ShipConstructionPremiumonpage33fortheincreasedcosts.)
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Limited Bunkering InfrastructureFor LNG tobecomeanattractive fuel forthe majority of ships, a global network of LNG bunkering terminals must beestablishedorLNGfueledshipswillbelimitedtocoastaltradeswhereanLNGbunkering network already exists. The situation is sometimes described as a
chickenandeggdilemma.Untilthebunkeringinfrastructureisinplace,shipownersmaynotcommittonaturalgasfueledshipsandvisaversa.Currently,LNGbunkering ismoreexpensiveandcomplicatedascompared towhat is inplaceforfossilfuelandisonlyavailableinalimitednumberofplaces.
AGLarticlecalledLNGSupplyChain(Ref.49)madethefollowingobservation:
o Attheendof2011,nosupplychainforLNGasshipfuelexists,withtheexception of that serving Norwegian coastal waters. The primary reason
forthisisthatLNGsuppliershaveyettobeconvincedthatthistechnologywilltakeoff.Moreover,LNGusershavetobeconvincedthatLNGwillbemadeavailableatattractivepricelevelsandtherightlocations.
o In principle, Europe is well prepared for this future as local LNGproduction is up and running in Norway.A number of large LNG importterminalsalreadyexist,withsomeof thesehavingorplanninganexportfacility,which isanecessarysteptowardssmallscaleLNGdistribution.Atpresent,however,largeLNGterminalsarenotyetequippedforexporting
smallerquantitiesofLNG.
Since these statements were issued, studies have been undertaken to equipLNGbunkeringfacilitieswithintheEuropeanECAstohaveLNGsupplycapacityby2015;andprojectshavebeenstartedtoprovideLNGbunkeringcapabilitiesat some ports. Major 0il and gas producers are showing an interest indeveloping an LNG marine fuel supply infrastructure. Shell has acquiredNorwegianLNGproduceranddistributorGasnor for$74millionwithplans totarget European marine customers. The purchase of Gasnor will give the oil
majora foothold intheemergentmarket forLNGbunkering.GasnorsuppliesLNG to Norway primarily by truck and is in the process of establishing LNGquayside bunkering at the German Port of Brunsbuttel (Ref.50). A plan hasbeendevelopedand land setaside foran LNGbunkeringport inRotterdam.AlthoughalargeGasAccesstoEurope(GATE)LNGimportterminalopenedattheendoflastyear,thisLNGisdestinedmostlyforpowerplants.Theprincipalcompanies involved want to build a smaller outbound terminal next to theGATE so the LNG can be supplied as fuel for ships (Ref. 51). The Port ofRotterdam and the Port