SCIENTIFIC UNDERSTANDING IN 2003 vs. 1999
Green bars are
updated values,
with arrows
updated
uncertainty.
© 2003 Waitz
32
RADIATIVE IMBALANCE AT TROPOSPHERE DUE
TO AIRCRAFT
© 2003 Waitz
(IPCC Special Report on Aviation, 1999)
35
NOTES ON CLIMATE CHANGE IMPACTS
• Burning a gallon of fuel at 11km has about double the radiative
impact of burning a gallon of fuel at sea-level
• Burning a gallon of fuel at 19km has about 5 times the impact
at sea-level
• CO2 is not the biggest global concern (potential impacts from
contrails and cirrus clouds are greater).
• Large imbalance between northern and southern hemisphere
• Improving engine efficiency tends to make NOx and contrails
worse
• High uncertainty
© 2003 Waitz
36
THE ROLE OF TECHNOLOGY:
CHARACTERISTICS OF AVIATION SYSTEMS
© 2003 Waitz
•
Safety critical
•
Weight and volume limited
•
Complex
•
10-20 year development times
•
$30M to $1B per unit capital costs
•
25 to 100 year usage in fleet
•
Slow technology development and uptake
37
COMMERCIAL vs. MILITARY FLEET TRENDS
• Demand growth for civil aviation (3.8%/year in US)
• Military fleet contraction
• Ops tempo (4.3/day commercial, 0.35/day military)
Number of Aircraft
© 2003 Waitz
Flights/day
40
FUEL CONSUMPTION TRENDS
Aircraft responsible for 2%-3% of U.S fossil fuel use
© 2003 Waitz
41
COMMERCIAL AIRCRAFT EFFICIENCY
Average Age = 13 yrs
© 2003 Waitz
42
MILITARY AIRCRAFT FUEL BURN
Average Age
21 yrs
© 2003 Waitz
43
ENERGY EFFICIENCY
• Function of performance of entire system
– Aircraft technology (structures, aerodynamics, engines)
– Aircraft operations (stage length, fuel load, taxi/takeoff/landing time, flight altitude, delays, etc.)
– Airline operations (load factor)
• Each component of system can be examined independently
for reduced fuel burn and impacts on local air quality and
regional/global atmospheric effects
© 2003 Waitz
44
RANGE EQUATION
Technology and Operations
Stage Length =
(
) ln1 +
V L D
g ⋅ SFC


Wpayload

Wfuel
+ Wstructure + Wreserve 
= Technology
= Operations
Efficiency ∝
Wpayload ⋅ StageLength
,
Wfuel
Use data to separate
effects and understand
influences of technology
ASK Stagelength ⋅ # seats
=
Wf
kgfuel
g
© 2003 Waitz
45
TRENDS IN LOAD FACTOR
0.8
0.7
Large Aircraft
Regional Jets
Load Factor
0.6
0.5
Turboprops
0.4
0.3
0.2
0.1
0.0
1965
1970
1975
1980
1985
Year
1990
1995
2000
Babikian, Raffi, The Historical Fuel Efficiency Characteristics of Regional Aircraft From Technological, Operational, and Cost
Perspectives, SM Thesis, Massachusetts Institute of Technology, June 2001
© 2003 Waitz
46
FLIGHT AND GROUND DELAYS
1.0
0.9
0.8
Ratio
0.7
0.6
0.5
0.4
0.3
Airborne to Block Hours
Minimum Flight to Airborne Hours
Mininum Flight to Block Hours
0.2
0.1
0.0
1965
1970
1975
1980
1985
1990
1995
2000
Year
© 2003 Waitz
47
HISTORICAL TRENDS
Aerodynamic Efficiency
25
F28-1000
F28-4000/6000
20
S360
A310-300
A320-100/200
RJ200/ER
B757-200
B747-100/200/300
F27
F100
B767-200/ER
BAC111-200/400
ATR72
S340A
L/Dmax
15
DC10-30
B707-100B/300
B707-300B
B737-100/200
DC9-30
DC10-10
B727-200/231A
L1011-500
L1011-1/100/200
DC10-40
B767-300/ER
ATR42
A300-600
DHC8-300
MD11
BAE-ATP
D328
B737-300
EMB120
B737-500/600
MD80 & DC9-80
B737-400
BAE146-100/200/RJ70
BAE-146-300
SA227
J41
J31
10
Babikian et al. (2002)
Data Unavailable For:
FH-227
EMB-145
Nihon YS-11
CV-880
SA-226
BAE RJ85
DHC-8-100
Beech 1900
L-188
CV-580
DHC-7
CV-600
5
Turboprops
Regional Jets
Large Aircraft
0
1955 1960
© 2003 Waitz
B777
B747-400
1965 1970 1975
1980 1985 1990
Year
1995 2000
48
HISTORICAL TRENDS
Engine Efficiency
30
B707-300
B720-000
25
B727-200/231A
BAC111-400
DC9-40
F28-4000/6000
BAE146-100/200/RJ70
CV880
TSFC (mg/Ns)
F28-1000
B737-300
DC9-50
BAE-146-300
DC9-30 B737-100/200
20
MD80 & DC9-80
F27
15
DC9-10
L188A-08/188C
CV580
RJ85
D328
EM170
F100
EMB145
B767-300/ER
L1011-500
B737-500/600
B737-400
DC10-30
B747-100
B757-200
RJ700
RJ200/ER
B747-200/300
L1011-1/100/200
B747-400
EMB135
B767-200/ER
CV600
DC10-40
MD11
DC10-10
A300-600
B777
A320-100/200
A310-300
J31
SA226
B1900
SA227
DHC7
J41
EMB120
S360
ATR72
D328
ATR42
DHC8-100
BAE-ATP DHC8-300
DHC8-400
S340A
10
Babikian et al. (2002)
5
0
1955
Turboprops
Regional Jets
Large Jets
New Regional Jet Engines
New Turboprop Engines
1960
1965
1970
1975
1980
Year
© 2003 Waitz
1985
1990
1995
2000
2005
49
HISTORICAL TRENDS
Structural Efficiency
0.70
DHC8-100
J31
B727-200/231A
CV600
0.60
F28-1000
BAC111-200
BAC111-400
DC9-10
FH227 DC10-10
B737-100/200
F27
0.50
DC9-40
L188A-08/188C
CV880
OEW/ MTOW
DHC7
DC9-30
SA227
S360
BAE146-100/RJ70
SA226
BAE146-200
B1900
EMB120
S340A
BAE-ATP
ATR42
D328
ATR72
J41
DHC8-300
RJ200/ER
B737-500/600
F100
MD80 & DC9-80
B737-300
BAE-146-300
L1011-1/100/200
B757-200
F28-4000/6000
A320-100/200 RJ85
B767-200/ER
B737-400
A300-600
DC9-50
B747-200/300
A310-300
B747-400
DC10-40
B767-300/ER
B777
L1011-500
DC10-30
MD11
EMB145
B747-100
0.40
B707-300B
0.30
0.20Babikian et al. (2002)
0.10
Turboprops
Regional Jets
Large Aircraft
0.00
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
Year
© 2003 Waitz
50
EFFICIENCY
Regional Jets Versus Turboprops
6
5
Energy Usage (MJ/ASK)
BAC111-400
4
Regional
Jet Fleet
Regional
Aircraft Fleet
CV880
BAC111-200
CV600
3
RJ200/ER
B1900
F28-1000
L188A-08/188C
BAE146-100
F28-4000/6000
F27
J31
DHC7
SA226
S360
2
RJ85
SA227
BAE-146-300
F100
Turboprop
Fleet
J41
D328
EMB145
BAE146-200
DHC8-300
DHC8-100
ATR72
S340A
EMB120
Babikian et al. (2002)
1
ATR42
BAE-ATP
Turboprops
Regional Jets
0
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
Year
© 2003 Waitz
51
ENERGY USAGE
Total Versus Cruise
5
EU,CR Large Aircraft
Total EU Large Aircraft
EU,CR Regional Aircraft
Total EU Regional Aircraft
4
Babikian (2001)
MJ/ASK
3
2
1
0
1955
© 2003 Waitz
1960
1965
1970
1975
1980
Year
1985
1990
1995
2000
52
COMMERCIAL AIRCRAFT ENERGY INTENSITY TRENDS
• New technology energy intensity has been reduced 60% over last 40
years (jet age)
– 57% due to increases in engine efficiency
– 22% due to increases aerodynamic performance
– 17% due to load factor
– 4% due to other (structures, flight time efficiency, etc.)
– Structural efficiency constant (but traded for aero, passenger
comfort, noise and SFC)
– Flight time efficiency constant (balance of capacity constraints and
improved ATM)
• Fleet average energy intensity has been reduced 60% since 1968
– Lags new technology by 10-15 years
© 2003 Waitz
53
COMPARISON TO OTHER TRANSPORT MODES
(Mark Janes, Boeing, in ICAO CAEP/5, 2002)
© 2003 Waitz
54
SHORT HAUL AIRCRAFT
Facing Increasing Scrutiny
3.5
Jets
Turboprops
(Babikian, 2002)
3.0
EU (MJ/ASK)
2.5
2.0
1.5
1.0
0.5
Aircraft introduced during or after 1980 only
0
0
1000 2000 3000 4000 5000 6000 7000 8000 9000
Royal Commission on the
Environment (2002)
“…deeply concerned at
the prospect of continuing
rapid increases in air
transport, particularly an
increase in short haul
flights…”
“It is essential that the
government should divert
resources...encouraging
and facilitating a modal
shift from air to highspeed rail.”
Stage Length (km)
© 2003 Waitz
55
IMPACT OF NASA TECHNOLOGY SCENARIOS
Billion Kg
2000
Global CO2 Emitted per Year
1750
Effect of Proposed Environmental CO2 Goals
No Improvement Beyond 1997 Technology
25% Reduction Introduced in 2007
50% Reduction Introduced in 2022
Zero CO2 Emission A/C Introduced in 2027
Zero CO2 Emission A/C Introduced in 2037
Change Relative to 1990:+340%
1500
+230%
( - GA and Military Emissions based on Boeing forecast
- IPCC IS92a based ICAO demand model
- No retrofit of technologies)
1250
+140%
1000
U.S. DOE reported fuel use
750
+40%
500
250
1990-5% Level
Emission inventories
0
1990
2000
Kyoto Protocol
Timing For Reductions
2010
2020
-20%
2030
2040
2050
Year
© 2003 Waitz
J. E. Rohde, NASA 1999
56
IMPACTS OF MISSION REQUIREMENTS (NOx & Noise)
•
Range/payload ~ fuel efficiency (commercial and military)
– Thermal efficiency
High pressures and
High NOx
temperatures
– Propulsive efficiency
Large mass flow with small
velocity change
Low Noise
• Maneuverability (military)
– High thrust-per-weight,
small compact engine
• Supersonic flight (military)
– Low drag, small compact
engine
© 2003 Waitz
High energy conversion per
unit volume (high
High NOx
temperatures and
pressures)
Small mass flow with large
velocity change
High Noise
57
NOx EMISSIONS TECHNOLOGY TRENDS
© 2003 Waitz
58
NOx EMISSIONS TRENDS
© 2003 Waitz
59
HISTORICAL FLEET CRUISE EMISSIONS PER
PASSENGER PER KILOMETER
Relative Emission / Pass-km
1.0
NOx
CO2 ,
H2 O
0.5
CO
HC
0
1975
1980
1985
Year
© 2003 Waitz
1990
1995
(DuBois, Boeing)
60
TECHNOLOGY AND EMISSIONS
• Improvements will not keep up with growth
• Aircraft typically have greater impact per unit of fuel burned
• “Solutions” for global climate will require unprecedented action
(demand management/regulations, electric vehicles, contrail avoidance,
etc.)
• Current understanding is that hydrogen makes problem worse
• High uncertainty relative to global impacts
• Engine efficiency improvements exacerbate NOx and contrails
• Significant improvements in structural efficiency, aero and operations
are possible
– Improvements in these areas do not exacerbate other problems
© 2003 Waitz
61
SUMMARY
• Broad range of environmental impacts from aircraft
– Social costs of same order as industry profits
– Currently not internalized
– Current technology path and regulations not aligned
with social costs
• Strong growth in demand
• Increasing public concern/regulatory stringency
• High uncertainty
• Many competing trades
– Environmental impacts
– Design, operations
© 2003 Waitz
62
SELECTED REFERENCES
•
Babikian, R., Lukachko, S. P. and Waitz, I. A. "Historical Fuel Efficiency Characteristics of
Regional Aircraft from Technological, Operational, and Cost Perspectives,” Journal of Air
Transport Management, Volume 8, No. 6, pp. 389-400, Nov. 2002
•
Lee, J. J., Lukachko, S. P., Waitz, I. A., and Schafer, A., “Historical and Future Trends in
Aircraft Performance, Cost and Emissions,” Annual Review of Energy and the
Environment, Volume 26, 2001.
•
Waitz, I. A., Lukachko, S. P., and J. J. Lee, "Military Aviation and the Environment:
Historical Trends and Comparison to Civil Aviation," AIAA-2003-2620, invited contribution
to AIAA/ICAS International Air and Space Symposium and Exposition, Dayton, Ohio, July
14-17, 2003.
•
Marks, D. H., et al., "Mobility 2001", World Business Council for Sustainable Development,
Switzerland, 2001.
•
Miake-Lye, R.C., Waitz, I.A., Fahey, D.W., Kolb, C.E., Wesoky, H.L., and Wey, C.C., “Aviation
and Climate Change,” Aerospace America, September, 2000.
•
Penner et al., United Nations Environment Programme, Intergovernmental Panel on
Climate Change (IPCC), Special Report on Aviation and the Global Atmosphere, 1999.
•
RCEP, “The Environmental Effects of Civil Aircraft In Flight,” Royal Commission on
Environmental Pollution (RCEP), England, December, 2003
© 2003 Waitz
63