1
The Global Potential for CO2 Emissions Reduction from Jet Engine Passenger Aircraft
Paper 18-04002
Lynnette Dray, Andreas Schäfer and Kinan Al Zayat
Air Transportation Systems Laboratory, UCL Energy Institute, University College London
97th TRB Annual MeetingWashington DC, 7-11 January 2018
2
Background• Assessingemissionsmitigationpolicyrequiresassessmentof
themeasuresthatareavailablewithin-sector• CORSIAoffsetsemissions,butitsimpactwilldependonfueluse,which
dependsoncost-effectivefuelburnreductionmechanisms• ChangesintechnologywillalsoaffectaviationNOx,contrails,PM,noise
etc.• StartfromSchäferetal.(2016)
• MarginalabatementcostsforUSnarrowbody aircraft• Showed2%/yearcost-effectivereductioninfueluse/RPKto2050is
plausible• Butfeweropportunitiesexistforotheraircraft
• Extendanalysistootheraircrafttypesandregions• Useaglobalaviationsystemsmodel(AIM)tocheckhow
adoptionwouldlookinpractice• Alsoassesshowthischangeswithincreasingcarbonprice
2
Typesofwithin-sectormitigationmeasures• Incrementalupdatestoconventionaltechnology• E.gA320neo,737MAX
• Radicalnewtechnologies• E.g.CRPengines,blendedwingbodyaircraft
• Retrofits• E.g.Re-engining,lightweighting
• Operational• E.g.CDM,optimisedrouting,reducedtankering
• Biofuels• Directemissionsmayremainthesame,reductioninfuel
lifecycleemissions
2
Updatestoconventionaltechnology- 1• Fuel/RPKwillstill
decreaseforconventionaltechnology:• Fleetturnoverremoves
olderaircraftfromthefleet
• Newaircraftbecomingavailable(e.g.A320neo,A330neo,E-JetE2,737MAX,777-X...)
• Furtherfutureimprovementsexpected• Moreuseofcomposites• Higherbypassratio
engines• Greaterlift/drag
(a) Small RJ350 km73% LF0.00
0.02
0.04
0.06
0.08
0.10
Fuel
per
RPK
, kg
HistoricalFuture projection
(b) Large RJ550 km75% LF
(c) Small SA750 km76% LF
(d) Medium SA750 km76% LF0.00
0.02
0.04
0.06
0.08
Fuel
per
RPK
, kg
(e) Large SA1000 km75% LF
(f) Small TA1750 km70% LF
(g) Medium TA1750 km70% LF0.00
0.01
0.02
0.03
0.04
0.05Fu
el p
er R
PK, k
g
1960
1980
2000
2020
2040
2060
Year
(h) Large TA5500 km77% LF
1960
1980
2000
2020
2040
2060
Year
(i) VLA5500 km77% LF
1960
1980
2000
2020
2040
2060
Year
[Data:Piano-X(Lissys 2016);ownprojections]
2
Updatestoconventionaltechnology- 2• Forthispaper:
• Assumepublishedcharacteristicsfornextgeneration• Forsubsequentgenerations,20(15-25)yeargap,0.7(0.5-1)%/year
reductioninfuelburnTechnology Sizeclass
AvailablefromCapitalcost,millionUS$(2015)
Changeinnon-fuelyearlycost,millionUS$(2015)
Changeinblockfueluse,%
References
Nextgenerationconventional
SmallRJ 2020(2018-2025) 40.9(35.7-46.1) -0.35(- 0.3- -0.47) 16(15-21) Embraer (2016);AlZayat &Schäfer (2017);Airbus(2017);Schäfer etal.(2016);Vera-Moralesetal.(2011);Leahy(2013);Reuters(2013);Airbus(2017)
LargeRJ 2020(2018-2025) 53.6(46.8-60.4) -0.4(-0.35- -0.55) 16(15-21)SmallSA 2019(2018-2020) 69.6(64.7-74.6) - 20(15– 22)MedSA 2016 75.8(70.4-81.3) - 20(15– 22LargeSA 2018(2017-2019) 88.9(82.5-95.2) - 20(15– 22)SmallTA Noupdate;referenceaircraftisalreadybasedonthe787-800MedTA 2020(2018-2022) 211(189– 233) -0.026 12(10– 14)LargeTA 2020(2018-2022) 251(233-270) -0.35(0– 0.07) 21(17.5– 23.7)VLA 2020(2017-2022) 305(284-323) -0.2(0– 0.4) 4
Subsequentgenerationconventional
SmallRJ 2040(2033-2050) 41(36-46) -0.35(- 0.3- -0.47) 28(25– 32)LargeRJ 2040(2033-2050) 54(47-60) -0.4(-0.35- -0.55) 28(25– 32)SmallSA 2039(2031-2045) 75(68– 82) - 30(26– 34)MedSA 2036(2031-2041) 83(75– 90) - 30(26– 34)LargeSA 2038(2032-2044) 97(87– 106) - 30(26– 34)SmallTA 2032(2027-2037) 123(114– 132) - 14(12– 14)MedTA 2040(2033-2047) 211(188– 233) -0.026 24(22– 24)LargeTA 2040(2032-2047) 251(233– 270 -0.35(0– 0.07) 31(29– 33)VLA 2042(2039-2045) 306(284– 324) -0.2(0– 0.4) 17(15– 17)
2
Alternativetechnologies- 1• Potentiallyupcoming
aircrafttechnologiesinclude:• Contra-rotating
propellorengines(CRP)
• Blendedwingbody(BWB)aircraft
• NASAN+3designs(includingdoublebubble)
• Batteryand/orturboelectricaircraft
• Hydrogenfuelledaircraft
• Advanced/optimisedturbopropdesigns
• Characteristicsandtimelineuncertain
[Images:NASA;Wikimediacommons]
BWB
CRP
AdvancedTP
DoublebubbleTurboelectric
Batteryelec.
(Approximate)EISestimate
2
Alternativetechnologies- 2• Forthispaper:
• Concentrateonrelativelywell-establisheddesigns:• Costestimatesavailable• Wouldrequirelittle/noadjustmenttocurrentinfrastructure• Assumeglobalavailability,aircraftchoicebasedoncostonly
• Excludes:NASAN+3,batteryelectric/turboelectricdesigns,hydrogenaircraft,nextgenerationsupersonicetc.
Technology Sizeclass Availablefrom Capitalcost,millionUS$(2015)
Changeinnon-fuelyearlycost,millionUS$(2015)
Changeinblockfueluse,%
References
AdvancedTurboprop
SmallRJ 2030(2025-2035) 22(19– 24) 1.7(0.9– 2.6) 43(37– 46) Vera-Morales etal.(2011);Liebeck (2004);Schäfer etal.(2016)
LargeRJ 2030(2025-2035) 28(24– 31) 1.7(0.9– 2.6) 43(37– 46)
OptimisedCRP
SmallSA 2035(2030-2040) 73(61– 85) 0.4(0.2– 0.5) 41(40– 45)MedSA 2035(2030-2040) 98(82– 115) 0.4(0.2– 0.6) 41(40– 45)LargeSA 2035(2030-2040) 99(83– 116) 0.4(0.2– 0.6) 41(40– 45)
Blended-WingBody
SmallTA 2040(2035-2045) 217(180– 289) -0.3(-0.2- -0.5) 30(15– 40)MedTA 2040(2035-2045) 233(194– 310) -0.3(-0.2- -0.5) 30(15– 40)LargeTA 2040(2035-2045) 249(207– 332) -0.3(-0.2- -0.5) 30(15– 40)VLA 2040(2035-2045) 364(303– 485) -0.3(-0.2- -0.5) 30(15– 40)
2
Retrofits
Technology Sizeclass Availablefrom
Capitalcost,millionUS$(2015)
Changeinnon-fuelyearlycost,millionUS$(2015)
Changeinfueluse,%
References
Blendedwinglets SmallSA– MedTA 2015 0.85– 1.9 - 3(2– 4) Schäfer etal.(2016);Morrisetal.(2009)
SurfacePolish SmallRJ– MedTA 2015 0.03– 0.13 0.03– 0.16 1(0.5– 1.5)CarbonBrakes SmallRJ– VLA 2015 - 0.015– 0.045 0.15(0.1– 0.2)
EngineUpgradeKit SmallRJ– MedTA 2015 0.5– 1.8 - 1(0.5– 1.5)Re-engining SmallRJ– MedTA 2015 7.1– 16.6 - 12.5(10– 15)ElectricTaxi SmallRJ– VLA 2018 0.3– 4 - 2.8(1.8-3.8)CabinWeightReduction
SmallRJ– VLA 2015 0.2– 2.3 - 1.2(1.2– 2.1)
• Canbeappliedtoexistingaircraft,souptakedoesnotdependonfleetturnover• SomemaybeapplicableonlyatD-check• Manyareapplicabletoonlypartofthefleet,e.g.aircraftwithout
wingletsorwitholderengines
2
Operationalmeasures- 1
Measure Sizeclass Availablefrom
Cost,millionUS$(2015)
Changeinfueluse,%,foraffectedflightphase
References
Surfacecongestionmanagement
SmallRJ– VLA 2015 0.015– 0.06 15(10– 20) Marais etal.(2013);Schäfer etal.(2016)
Singleenginetaxi SmallRJ– VLA 2015 0– 0.06 30(20– 40)
Optimizedepartures SmallRJ– VLA 2015 0.2– 0.6 20(10– 30)
Reducecruiseinefficiency
SmallRJ– VLA 2015 0.07– 0.13 5.5(2.8– 8)
Optimizeapproach SmallRJ– VLA 2015 0.2– 0.6 40(15– 50)
• Strategiestoreduceroutinginefficiencyand/orairportcongestion
• Manyoptions,e.g.CDAs,CDM,routeoptimization
• WegroupmeasuresintobundlesasinMaraisetal.(2013)
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Operationalmeasures- 2• Canalsoconsiderchangesinairlinebehaviour,e.g.
• Tankeringand/orusingfuelreservesabovetheminimumrequired• Maintenanceinterval• Changesinfrequency,loadfactororaircrafttypeuse• Will(probably)beadoptedif/whencost-effective,butcostsmaybe
difficulttoestimate
Measure Sizeclass Availablefrom
Cost,millionUS$(2015)
Changeinfueluse,% References
Reducedfuelreserves SmallRJ– VLA 2015 0– 0.5 0.01– 0.4 Schäfer etal.(2016);Morrisetal.(2009);Henderson(2005)
Reducedtankering SmallRJ– LargeSA 2015 0 0.26(0.34– 0.27)
Increasedenginemaintenance
SmallRJ– VLA 2015 0.001– 0.002 2.4(1– 4)
Increasedaerodynamicmaintenance
SmallRJ– VLA 2015 0.001– 0.002 1(0.2– 1.5)
Enginewash SmallRJ– VLA 2015 -0.1– 0.09 0.75(0.25– 1)
IncreasedLF/reducedfrequency
SmallRJ– LargeSA 2015 0.2– 7.6 0
Increasedturbopropuse SmallRJ– LargeRJ 2015 2.6 30(25– 32)
2
Alternativefuels- 1• Manydifferentoptions(e.g.Hileman&Stratton2014)• Fuelsrequiringchangesinaircraftdesign(e.g.hydrogen)would
needalongtimetopercolateintothefleet• Drop-infuel(e.g.F-Tbiomassfuels)uptakecanbefaster,but
limitedbyinfrastructure,supply,certificationrequirements• Manyfeedstockoptions,e.g.algae,cellulosicbiomass
• Drop-inbiofuelshavealreadybeentrialled,butnowidespreaduse
• Aviationbiofuelsupplywilldependontheamountofbiomassusedbyothersectors• Potentialfordouble-countingemissionsreductions• E.g.manyfuturescenarios assumebiomassisusedinpower
generation
2
Alternativefuels- 2• Inthispaper:
• Assumeadrop-incellulosicbiomassfuel• Relativelylowprojectedcosts,loweruncertaintythanalgaefuels• Doesnotcompetewithfoodproduction
North America
0
5
10
15
Biof
uel d
eman
d, G
J
Europe
0
5
10
15
20
25
30
Biof
uel d
eman
d, G
J
0 1 2 3 4 5 6Biofuel price, $(2015)/gal
Asia/Pacific
05
101520253035
Biof
uel d
eman
d, G
J
0 1 2 3 4 5 6Biofuel price, $(2015)/gal
Year2020202520302035
204020452050
• Costdependsondemand• UseHoogwijketal.(2009)/
Searle&Malins(2014)/DoE(2011)togeneratebiomasscostcurvescenarios
• Plantandtransportcostsassumedtoadd$3.6/galin2020,fallingto$1.8(1.3–2.3)/galin2050
• Priorityaccessforaviationassumed,butalsorunwithoutbiofuels
3
IntegratedModelling
• Toestimatetheachievablebenefitsfromthesemeasuresweneedtoestimate:• Uptakebyairlinesindifferentfutureconditions
• Requiresmodeloffleetandfleetturnover• Uptakecriteria(e.g.NPVwith10%discountrate)• Modelofearly/lateadopters(Kar etal.2009)
• Anyinteractionsbetweenmeasures• Themagnitudeoffeedbackeffects
• E.g.bettertechnologylowerscosts,airlinesreducefares,demandincreases,emissionsgoup
• Earlyadoptionofonemeasureaffectslateradoptionofanothermeasure
• Toaccountfortheseeffectsweuseaglobalaviationsystemsmodel(AIM)
3
AviationIntegratedModelling(AIM)
• Global,open-sourceaviationsystemsmodel
• Recentlyupdatedto2015baseyear
• SeeDrayetal.(2017)forvalidationstudy
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Futurescenarios
• Needprojectionsof:• Population• GDP/capita• Oilprice• Carbonprice
• UseIPCCSSPscenarios
• Basecasenocarbonprice• Useasa
sensitivityvariable
[Data:O’Neilletal.,2013;DECC,2015]
(a) Population
0.6
0.8
1.0
1.2
1.4
Popu
latio
n,ra
tio w
ith 2
015
SSP1SSP2SSP4
(b) GDP per capita
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Cons
tant−p
rice
MER
GDP
per c
apita
, rat
io w
ith 2
015
DECC LowDECC MidDECC High
(c) Oil price
0
50
100
150
200
250
300
Oil p
rice,
year
201
5 do
llars
/bbl
2000
2010
2020
2030
2040
2050
2060
Year
Level 1Level 2Level 3
(d) Carbon price
0
50
100
150
200
Carb
on p
rice,
yea
r20
15 d
olla
rs/tC
O2
2000
2010
2020
2030
2040
2050
2060
Year
10
Modeluncertainty
SSP1pessimistic
SSP1central
SSP1optimistic
SSP2pessimistic
SSP4pessimistic
SSP4optimistic
SSP2central
SSP2optimistic
SSP4central
Earlier/better/cheapertechnology
Higherdem
andgrow
th
• Manysourcesofuncertainty• Wearemostinterestedin:
q Uncertaintyindemand§ RunthreescenariosforGDP/population/fuelprice
q Uncertaintyintechnologycharacteristics§ Runthreelenses§ E.g.centralcaseusesmostlikelyestimates
§ Optimisticcaseassumesearlyavailability,lowcostandfueluse
§ Pessimisticcaselateavailability,etc.
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Futureprojections- 1
• RPKgrowthof3.0– 5.5%/year2015-2035byscenarioq MainlyduetodifferentGDPand
fuelpriceprojectionsq Technologyscenario+/- 0.1%/yearq CentralSSP2scenariogrowsat
4.4%/yearto2036q ComparabletoAirbus(2016),
Boeing(2016)4.5and4.8%/year,nexttwentyyears
• Uncertaintyintechnologycharacteristicshasalargeimpactonfleetcomposition
• Relativelysmalldifferenceswith/withoutbiofuel [Pastdata:FlightGlobal,2016]
20
40
60
80
100
120
Flee
t, th
ousa
nd
SSP1
Pessimistic Central Optimistic
20
40
60
80
100
120
Flee
t, th
ousa
nd
SSP2
20
40
60
80
100
120
Flee
t, th
ousa
nd
2000
2010
2020
2030
2040
2050
2060
Year
SSP4
2000
2010
2020
2030
2040
2050
2060
Year
2000
2010
2020
2030
2040
2050
2060
Year
Current (Jet)NEO (Jet)NextGen (Jet)
FutureGen (Jet)NextGen (OR)BWB
TurbopropAdv. Turboprop
RPK over time
0
10000
20000
30000
40000
50000
60000
RPK,
billi
on SSP1SSP2SSP4Past data
2050 RPK by carbon price
0
10000
20000
30000
40000
RPK
in 2
050,
billi
on
Lifecycle CO2 over time
OptimisticCentralPessimistic
0
1000
2000
3000
4000
Fuel
lifec
ycle
CO
2, M
t
1980
2000
2020
2040
2060
Year
2050 CO2 by carbon price
0
500
1000
1500
2000
2500
3000
Fuel
lifec
ycle
CO
2 in
205
0, M
t
0 50 100 150Carbon price in 2050, year 2015 USD
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Futureprojections- 2
• Year-2050fuellifecycleCO2variesbetween620and1690Mt
q Withoutbiofuels,1630– 3400Mt
• 1.9-3.0%/yearreductioninlifecyclefuel/RPKto2050
q Withoutbiofuels,0.8– 1.6%/year
q USdomesticnarrowbody similartoSchäfer etal.(2016)
• CarbonpriceprimarilyaffectsemissionsviaRPKatlevelsmodelled
q Relativelysmallimpactontechnologiesused
q Higherimpactifnobiofuel[Pastdata:ICAO,2016;IEA,2017]
Withbiofuels
11
Futureprojections- 2
• Year-2050fuellifecycleCO2variesbetween620and1690Mt
q Withoutbiofuels,1630– 3400Mt
• 1.9-3.0%/yearreductioninlifecyclefuel/RPKto2050
q Withoutbiofuels,0.8– 1.6%/year
q USdomesticnarrowbody similartoSchäfer etal.(2016)
• CarbonpriceprimarilyaffectsemissionsviaRPKatlevelsmodelled
q Relativelysmallimpactontechnologiesused
q Higherimpactifnobiofuel[Pastdata:ICAO,2016;IEA,2017]
RPK over time
0
10000
20000
30000
40000
50000
60000
RPK,
billi
on SSP1SSP2SSP4Past data
2050 RPK by carbon price
0
10000
20000
30000
40000
RPK
in 2
050,
billi
on
Lifecycle CO2 over time
OptimisticCentralPessimistic
0
1000
2000
3000
4000
Fuel
lifec
ycle
CO
2, M
t
1980
2000
2020
2040
2060
Year
2050 CO2 by carbon price
0
500
1000
1500
2000
2500
3000
Fuel
lifec
ycle
CO
2 in
205
0, M
t
0 50 100 150Carbon price in 2050, year 2015 USD
Withoutbiofuels
12
Conclusions• Therearesignificantemissionsreductionopportunitieswithin
theaviationsectorq Cost-effectivereductionsof1.9– 3.0%peryearinfuellifecycleCO2/RPK
to2050possible,dependingonfuelpriceandtechnologycharacteristicsq Abouthalfofthisisbiofuel-dependent
§ 0.8– 1.6%/yearwithnobiofuelatall
§ Outcomessensitivetobiofuelavailabilityandpricescenario
• Absoluteemissionsstillgoupto2050inallscenariosq However,GDPscenariohasalargeimpactontotalRPK,CO2
• Likelywithin-sectorimpactofCORSIAatprojectedcarbonpricesissmall(atleastinitially)
11
Extraslides
11
Futureprojections– Contributionbytype
• Influenceofdifferentmeasuresdependsontimescaleq Initialbenefitsfromoperationalmeasuresandretrofitswhichcanbe
appliedquicklyq Technologyimpactisslowerasitdependsonfleetturnoverq Biofueluptakedependsondevelopmentofproductionand
distributioncapacity
BiofuelAlt. Tech.Conv. Tech.RetrofitsOperational
Contributionof differentmeasure types,SSP2 central
20
40
60
80
Cont
ribut
ion
to L
ifecy
cleCO
2/RP
K re
duct
ion,
per
cent
1980
2000
2020
2040
2060
Year
2050 contribution bycarbon price, SSP2 central
20
40
60
80
Cont
ribut
ion
to L
ifecy
cleCO
2/RP
K re
duct
ion,
per
cent
0 20 40 60 80 120Carbon price in 2050, year 2015 USD
• Applyingacarbonpricedoesnothavemucheffectonrelativecontributionq Slightlyincreases
contributionofalternativetechnologyinno-biofuelscase
