Decarbonizing Aviation
UCSD Deep Decarbonization InitiativeUniversity of California San Diego
Wednesday November 6, 2019
Andreas W. SchäferAir Transportation Systems Laboratory (www.ATSLab.org)
University College London([email protected])
• Strong demand growth• Dependency on high-energy content fuels• High capital intensity• Long lifetime of equipage• Comparatively low profitability• Cost pressure has resulted in significant fuel efficiency improvements• Non-CO2 climate warming ≧ CO2 warming • No silver bullet
Key Sector Characteristics
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ClassicNext GenerationMAX
Mor
rell
P., D
ray
L.M
., 20
09. E
nviro
nmen
tal a
spec
ts o
f fle
ettu
rnov
er, r
etire
men
t and
life
cycle
, Fin
al R
epor
t, OM
EGA.
Long Technology Lifetime: Narrowbodies
Half of all aircraft introduced today will still operate in 2050
Driver of Fuel Efficiency: Low Airline Profit Margins
https://www.iata.org/publications/economics/Reports/chart-of-the-week/Chart-of-the-week-7-June-19.pdf
US Energy Information Administration. U.S. Kerosene-Type Jet Fuel Retail Sales by Refiners, Average Retail Prices of Electricity
CO2 is not the only Warming Agent
Le
e D
.S.,
Fa
he
y D
.W.,
Fo
rste
r P.M
., N
ew
ton
P.J
., W
it R
.C.N
., L
im L
.L.,
Ow
en
B.,
Sa
use
nR
., 2
00
9.
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iati
on
an
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n t
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ry,
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7.
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., AT
SLab
; dat
a: S
abre
, 201
7; IC
AO, 2
018
Demand Growth 2000-2016
Dray
L.M
., AT
SLab
; dat
a: S
abre
, 201
7; IC
AO, 2
018
Projected Demand at around 2030
Dray
L.M
., AT
SLab
; dat
a: S
abre
, 201
7; IC
AO, 2
018
Projected Demand at around 2050
CO2 Emissions Identity
CO2 = CO2
EE
RTK RTK
Air Transport Demand
EnergyIntensity
FuelComposition
CO2 Emissions
+5.4%/yr-3.2%/yr0+2.2%/yr1980-2015:+4.2%/yr-1.6%/yr0+2.6%/yr2015-2050:
CO2 Emissions Identity
CO2 = CO2
EE
RTK RTK
Air Transport Demand
EnergyIntensity
FuelComposition
CO2 Emissions
Energy intensity across modes: square cube law
Aircraft(US: 1991-2010)
Trucks(8 countries:1940-2010)
Railways(6 countries:1980-2010)
Gucwa M., Schäfer A., 2013. The impact of scale on energy intensity in freighttransportation, Transportation Research Part D: Transport and Environment, August.
Freight Transportation
Water Vessels
Schäfer A., Yeh S., A Holistic Perspective on Passenger Travel Energy and Greenhouse Gas-Intensities, under review.
Water Vessels
(3 sources: current
technology)
Passenger Transportation
Declining Energy Intensity
Le
e J
.J.,
Lu
ka
ch
ko
S.P
., W
ait
zI.
A.,
Sch
äfe
rA
., 2
00
1,
“H
isto
ric
al
an
d F
utu
re
Tre
nd
s
in A
ircra
ft P
erfo
rm
an
ce
, C
ost,
an
d E
mis
sio
ns”,
An
nu
al
Re
vie
w o
f E
ne
rg
y a
nd
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e
En
vir
on
me
nt 2
00
1,
26
: 1
67
-2
00
.
Scha
fer,
Evan
s, Re
ynol
ds, D
ray,
2015
. Co
sts o
f miti
gatin
g CO
2Em
issio
ns
from
Pas
seng
er A
ircra
ft, N
atur
e Cl
imat
e Ch
ange
, Dec
embe
r 201
5.
Marginal Abatement Costs: US Narrowbody Aircraft Fleet
First-order Fleet Impact
Schäfer A.W., Evans A.D., Reynolds T.G., Dray L., 2016. Costs of mitigating CO2 emissions from passenger aircraft, Nature Climate Change 6:412-418.
LocalEnvironment
Impacts
Local/NationalEconomicImpacts
GlobalEnvironment
Impacts
AircraftTechnology & Cost
AircraftMovement
Airline & Airport Activity
Air Transport Demand
Global Climate
Air Quality & Noise
Regional Economics
Modelling Aviation Systems
www.ATSlab.org
Modelling Aviation Systems
www.ATSlab.org
Future Aviation in a Non-Disruptive World: Key Model Inputs
(a) Population
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0.8
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1.4
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ith 2
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(b) GDP per capita
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(c) Oil price
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rice,
year
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llars
/bbl
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Level 1Level 2Level 3
(d) Carbon price
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on p
rice,
yea
r20
15 d
olla
rs/tC
O2
2000
2010
2020
2030
2040
2050
2060
Year Dray
L., S
chäf
erA.
W.,
Al Z
ayat
K., 2
018.
“Th
e Gl
obal
Pot
entia
l for
CO 2
Emiss
ions
Red
uctio
n fro
m Je
t Eng
ine
Pass
enge
r Airc
raft
”, Tr
ansp
. Res
. Re
c., 2
672(
23),
40-5
1.§
Future Aviation in a Non-Disruptive World: Technology Dynamics
20
40
60
80
100
120
Flee
t, th
ousa
nd
SSP1
Pessimistic Central Optimistic
20
40
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120
Flee
t, th
ousa
nd
SSP2
20
40
60
80
100
120
Flee
t, th
ousa
nd
2000
2010
2020
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2040
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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
20
40
60
80
100
120
Flee
t, th
ousa
nd
SSP1
Pessimistic Central Optimistic
20
40
60
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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
Technology Assumptions
Dray
L., S
chäf
erA.
W.,
Al Z
ayat
K., 2
018.
“Th
e Gl
obal
Pot
entia
l for
CO 2
Emiss
ions
Red
uctio
n fro
m Je
t Eng
ine
Pass
enge
r Airc
raft
”, Tr
ansp
. Res
. Re
c., 2
672(
23),
40-5
1.§
Future Aviation in a Non-Disruptive World: Key Model Outputs
Without biomass-to-liquids With biomass-to-liquids
Dray L., Schäfer A.W., Al Zayat K., 2018. “The Global Potential for CO2 Emissions Reduction from Jet Engine Passenger Aircraft”, Transp. Res. Rec., 2672(23), 40-51.
Industry Emissions Reduction Roadmap
Font
aP.,
Pus
hing
the
Tech
nolo
gy E
nvel
ope,
ICAO
Env
ironm
enta
l Rep
ort 2
010.
CO2 Emissions Identity
CO2 = CO2
EE
RTK RTK
Air Transport Demand
EnergyIntensity
FuelComposition
CO2 Emissions
Schäfer A., Sweeney J., Draft Paper, 2016
Fuel Shares: Yard, Passenger, and Freight Sector CO2 Intensity: Freight Railroads
Disruptive Technology Change in Rail Transportation
Kram
mer
P., 2
017.
Sim
ulat
ing
the
Impl
icat
ions
of E
miss
ions
Tra
ding
Sch
emes
for
Inte
rnat
iona
l Tra
nspo
rtat
ion”
, PhD
The
sis. U
CL E
nerg
y In
stitu
te, U
CL.
Force of Change: Economies of Scale
0.0001
0.001
0.01
0.1
1
10
100
0 1 10 100 1,000 10,000 100,0001,000,000
Ope
ratin
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sts,
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(201
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TK
Scale (= Load Factor x Capacity), RTK/VKT = (RTK/RTKavail · RTKavail/VKT)
US for-hire trucks
US freight aircraft(1994-2013)
US, Canada railroads(1995/6-2009/10)
Ocean: container, oil, LPG, bulk (2010-14)
.1
Winners LosersFuel Shares: Yard, Passenger, and Freight Sector
Disruptive Technology Change in Rail Transportation
Disruptive Technology Change in Air Transportation
0
10
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60
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1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050
Flee
t by
Engi
ne Ty
pe, %
Piston engine A/C
Jet engine A/C
Turboprop A/C
Force of Change: Increase in Productivity
0.0
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ts(1
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Aircraft Productivity, Seat-miles/day
Jet-engine aircraft
4-engine piston aircraft2-engine piston aircraft
Turboprop aircraft
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B-720
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DC-4
DC-7
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L-1049H
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nts
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Productivity, Seat-mi/h
Force of Change: Increasing Environmental & Societal Pressure?
• LH2: 120 MJ/kg but 8.5 MJ/L, capital-intensive infrastructure required from well-to-wake, potentially zero-carbon but increase H2O emissions• LNG: 50 MJ/kg vs. 23.4 MJ/L, capital-intensive infrastructure required
from well-to-wake, little to no benefit over jet fuel on lifecycle basis• Drop-in synthetic fuels (from biomass, H2 and CO2, etc.): 42.8 MJ/kg
vs. 34.7 MJ/L, upstream infrastructure change, potentially zero-carbon• Electricity: currently 200 Wh/kg (0.7 MJ/kg) but at least 4X required,
capital-intensive infrastructure required from well-to-wake, potentially zero-carbon and no non-CO2 warming
Alternative Aviation Fuels
0
50
100
150
200
250
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Net L
ifecy
cle C
O 2Em
issio
ns, g
CO2/
RPK
Primary Energy, MJ/RPK
Alternative Aviation Fuels
Coal
Crude Oil
Natural Gas
Renewables
All aircraft are assumed to have an energy intensity of 1 MJ/RPK
Ref.
Synfuel
LH2
LNG
Synfuel
LH2
LH2Synfuel (BTL) LH2 (Coal+CCS)
Solarfuels (PTL)
Impact of Biomass-based Synthetic Fuels on CO2 Intensity
Gu
cwa
M.,
Sch
äfe
rA
., 2
01
3.
Th
e i
mp
act
of
sca
le o
n e
ne
rgy
inte
nsi
ty i
n f
reig
ht
tra
nsp
ort
ati
on
, Tr
an
spo
rta
tio
n R
ese
arc
h P
art
D:
Tra
nsp
ort
an
d E
nvi
ron
me
nt,
Au
gu
st.
1
10
100
1,000
10,000
0 1 10 100 1,000 10,000 100,0001,000,000
Life
cycl
e C
arb
on
In
ten
sity
, g
CO
2/R
TK
Scale (= Load Factor x Capacity), RTK/VKT
Aircraft(US: 1991-2010)
Trucks(8 countries:1940-2010)
Railways(6 countries:1980-2010)
Water Vessels(3 sources: current
technology)
.1
BTL (80% CO2 intensity reduction)
• In the absence of disruptive technology, sector-wide net-zero CO2emissions can only be achieved through atmospheric CO2 removal, e.g., direct air capture (DAC)• Costs of DAC: $94-232/t(CO2)
(https://www.sciencemag.org/news/2018/06/cost-plunges-capturing-carbon-dioxide-air)• Very high costs in 2050: $150/t(CO2) x 1.5 bln t(CO2) = $225 bln or
$18 per PAX >> $6.12 net profit today• Detailed, airline-based modelling required to better understand
implications.
Removing CO2 from the Air
All-Electric Aircraft can eliminate CO2 and non-CO2 Warming
Le
e D
.S.,
Fa
he
y D
.W.,
Fo
rste
r P.M
., N
ew
ton
P.J
., W
it R
.C.N
., L
im L
.L.,
Ow
en
B.,
Sa
use
nR
., 2
00
9.
Av
iati
on
an
d G
lob
al
Cli
ma
te C
ha
ng
e i
n t
he
21
st
Ce
ntu
ry,
Atm
osp
he
ric E
nv
iro
nm
en
t 4
3(2
2–
23
):3
52
0-3
53
7.
Electric Aircraft Architectures (leading to Distributed Propulsion)
Natio
nal A
cade
mie
s of S
cienc
es, E
ngin
eerin
g, a
nd M
edici
ne. 2
016.
Com
mer
cial
Airc
raft
Prop
ulsio
n an
d En
ergy
Syst
ems R
esea
rch:
Red
ucin
g Gl
obal
Car
bon
Emiss
ions
. Was
hing
ton,
DC:
The
Nat
iona
l Aca
dem
ies P
ress
. doi
:10.
1722
6/23
490.
Jet engine aircraft: ! = #$%$&' ()
*+ ln
./0/1/23.4/023
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Breguet Range Equation
Propulsive PowerFuel energy / time
Propulsive PowerBattery Power
H: Fuel energy contentE: Battery specific energyL/D: Light-to-drag ratiom: Mass
(Breguet) Range Equation: All-Electric Aircraft
Hepp
erle
M.,
2012
. Ele
ctric
Flig
ht –
Pote
ntia
l and
Lim
itatio
ns. A
VT-2
09 W
orks
hop
on
Ener
gy E
fficie
nt Te
chno
logi
es a
nd C
once
pts O
pera
tion,
Lisb
on, P
ortu
gal,
pp. 1
–30.
Modelling All-Electric Aircraft Performance
Gnad
tA.R
., Sp
eth
R.L.
, Sab
nisJ
.S.,
Barr
ett S
.R.H
., 20
19. T
echn
ical a
nd e
nviro
nmen
tal
asse
ssm
ent o
f all-
elec
tric
180-
pass
enge
r com
mer
cial a
ircra
ft, P
rogr
ess i
n Ae
rosp
ace
Scie
nces
, 105
:1-3
0.
Battery Specific Energy has increased by � 3%/yr(A doubling every 20-25 years)
Koh H., Magee C.L., 2008. A functional approach for studying technological progress: Extension to energy technology, Technological Forecasting and Social Change 75(6):735-758
Crabtree G., Kócs E., Trahey L., 2015. The energy-storage frontier: Lithium-ion batteries and beyond. MRS Bulletin 40, 1067-1076.
All-Electric Aircraft Market Size by Distance
Sch
äfe
rA
.W.,
Ba
rre
tt S
.R.H
., D
oy
me
K.,
Dra
y L
.M.D
., G
na
dt
A.R
., S
elf
R.,
O’S
ull
iva
n
A.,
Sy
no
din
os
A.P
., T
ori
jaA
.J.,
20
19
. “
Te
ch
no
log
ica
l, E
co
no
mic
an
d E
nv
iro
nm
en
tal
Pro
sp
ects
of
All
-Ele
ctr
ic A
ircra
ft”,
Na
ture
En
erg
y 4
:16
0-1
66
.
Key Air Transportation Characteristics
SchäferA.W.,BarrettS.R.H.,DoymeK.,DrayL.M.D.,GnadtA.R.,SelfR.,O’Sullivan
A.,SynodinosA.P.,TorijaA.J.,2019.“Technological,EconomicandEnvironmental
ProspectsofAll-ElectricAircraft”,Na
ture
Energy
4:160-166.
Direct Operating Cost (DOC)
• Electrification affects 75% of DOC (capital costs, maintenance, energy, en-route / airport charges)• Capital costs: lower-cost propulsors, absence of fuel system and APU
versus higher-cost, first set of batteries• Maintenance costs: potentially lower engine maintenance costs versus
higher airframe maintenance and battery replacement costs• Cost-effectiveness depends mainly on battery performance and costs,
jet fuel and electricity price• 2015 jet fuel prices ($1.8/Gal) and advanced batteries (800 Wh/kg, $100/kWh)
would require electricity prices of max $0.05/kWh• A carbon tax of $100/tCO2 would allow electricity prices of max $0.09/kWh
Break-Even Electricity Price
SchäferA.W.,BarrettS.R.H.,DoymeK.,DrayL.M.D.,GnadtA.R.,SelfR.,O’Sullivan
A.,SynodinosA.P.,TorijaA.J.,2019.“Technological,EconomicandEnvironmental
ProspectsofAll-ElectricAircraft”,Na
ture
Energy
4:160-166.
Costs of Renewable Power are declining
Global weighted average CSP, solar PV, onshore and offshore wind project LCOE data to 2017 and auction price data to 2020, 2010-2020
IREN
A, 2
018.
Ren
ewab
le P
ower
Gen
erat
ion
Cost
s in
2017
, Int
erna
tiona
l Re
new
able
Ene
rgy
Agen
cy, A
bu D
habi
.
Aircraft Warming Intensity
180-Seat NarrowbodyAircraft, Range = 400 nmi
SchäferA.W.,BarrettS.R.H.,DoymeK.,DrayL.M.D.,GnadtA.R.,SelfR.,O’Sullivan
A.,SynodinosA.P.,TorijaA.J.,2019.“Technological,EconomicandEnvironmental
ProspectsofAll-ElectricAircraft”,
Natu
reEn
ergy
4:160-166.
180 Wh/RPK
Carbon Intensity of Electricity needs to decline strongly
Historical Trend
Future Projections for limiting ∆T to 2o
(EMF27 model comparison, 450 ppm scenario)
Da
ta s
ou
rce
: IP
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rio
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ata
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ttp
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IEA
, 2
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mm
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• Using all-electric aircraft for flight segments up to 400-600 nmi (741-1,111 km) within the 2015 flight network would result in extra electricity demand of• 110-340 TWh (0.6-1.7%) globally• 23-83 TWh (0.6-2.2%) US• 11-33 TWh (1.3-3.7%) UK
• Around 15% of all flights in early morning (overnight charging) àremaining 85% determine investments into new power generation capacity (assuming 35% capacity factor)• 31-120 GW globally• 6.6-27 GW (US)• 1.2-3.6 GW (UK)
Electric Power Implications
• Noise contours of All Electric Aircraft• Using MIT aircraft specs and flight profile
• Parametric study to evaluate noise vs.• Number of propulsors
• Battery specific energy
• Battery charging strategies
• Mission length
• Conclusions• Noise benefits could be substantial on short
missions
• Noise highly dependent on all operational constraints and procedures, i.e., flight profiles and recharging strategies
• Take-off noise lower than conventional aircraft, due to lower fan pressure ratios and absence of combustion noise
• Approach noise likely higher than conventional aircraft, due to higher aircraft weight
All-Electric Aircraft Noise Analysis
Sch
äfe
rA
.W.,
Ba
rre
ttS
.R.H
.,D
oy
me
K.,
Dra
yL.
M.D
.,G
na
dt
A.R
.,S
elf
R.,
O’S
ull
iva
n
A.,
Sy
no
din
os
A.P
.,To
rija
A.J
.,2
01
9.
“Te
chn
olo
gic
al,
Eco
no
mic
an
dE
nv
iro
nm
en
tal
Pro
spe
cts
of
All
-Ele
ctri
cA
ircr
aft
”,Na
ture
Energy
4:1
60
-16
6.
• To become a feasible alternative, all-electric aircraft require• significantly higher specific energy and power batteries• significantly higher specific power aircraft motors and power electronics• lower battery costs and enabling economic conditions
• Enabling technologies and factors• Electric air taxis• Turbo and hybrid-electric aircraft• New business models?
• Mutually reinforcing factors with time scales measured in decades• Rising battery performance and declining costs, electricity grid decarbonization,
strong decline in renewable power generation costs• R&D on all-electric aircraft design and key components needs to start now
Conclusions: Electric Aircraft Study
Electric Aircraft Research Team• Prof. Steven R.H. Barrett (MIT)• Dr. Lynnette Dray (UCL)• Dr. Khan Doyme (UCL)• Roger Gardner (U. Southampton)• Mr. Albert Gnadt (MIT)• Dr. Chez Hall (U. Cambridge)• Mr. Weibo Li (UCL)• Mr. Marius Macys (UCL)• Dr. Antonio Martinez (U. Southampton)• Prof. Andreas W. Schäfer (UCL)• Prof. Rod Self (U. Southampton)• Ms. Vanessa Schröder (ETH Zurich)• Dr. Aidan O’Sullivan (UCL)• Mr. Bojun Wang (UCL)• Mr. Kinan Al’Zayat (UCL)
Next Steps: Aviation Integrated Model with Airline Competition
• Each airline sequentially maximizes profit (P) within its network (objective fct.)• Three decision variables: airfare (F), flight frequency (FF), type of aircraft (a)
P = ∑ "#$ %& ' "#$ ()*& − ∑ ∑,-./0&123,5,0 ' %%5,0 − ∑ ∑,-.678,5,0 ' ()*5,0
• Set of around 10 linearized constraints• Iteration until equilibrium• IBM CPLEX linear programming solver
9:9#$ ;:<=> ;:<=>?:)/. ?:)/.
Revenues Flight-related costs PAX-related costs
Aviation Integrated Model: Sample Results – Australia
0
100
200
300
400
500
0 100 200 300 400 500
Pred
icte
d Se
gmen
t Airf
ares
, US$
Observed Segment Airfares, US$
Observed NetworkPAX flows
Generated NetworkPAX flows
R2 = 0.79N = 256
SYD
Itinerary Airfares
10
100
1,000
10,000
10 100 1,000 10,000
Pred
icte
d Se
gmen
t PAX
, 100
0
Observed Segment PAX, 1000
Segment PAX
R2 = 0.77N = 256
Doym
eK.
, Dra
y L.
M.,
ATSL
ab