scientific understanding in 2003 vs. 1999 · pdf filenotes on climate change impacts •...
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SCIENTIFIC UNDERSTANDING IN 2003 vs. 1999
Green bars are updated values, with arrows updated uncertainty.
© 2003 Waitz 32
RADIATIVE IMBALANCE AT TROPOSPHERE DUETO AIRCRAFT
(IPCC Special Report on Aviation, 1999)© 2003 Waitz 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
• 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
© 2003 Waitz 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 Flights/day
© 2003 Waitz 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/take-off/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 EQUATIONTechnology and Operations
Stage Length V L D
g SFC W
W W W fuel
payload structure reserve
=( ) ⋅
+ + +
ln 1
= Technology = Operations
Efficiency W StageLength
W
ASK kg
Stagelength seats
payload
fuel
fuel W
g f
∝∝
==
,
#
Use data to separate effects and understand influences of technology
© 2003 Waitz 45
TRENDS IN LOAD FACTOR
Load
Fac
tor
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Regional Jets
Turboprops
Large Aircraft
1965 1970 1975 1980 1985 1990 1995 2000 Year
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 DELAYSR
atio
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Airborne to Block Hours Minimum Flight to Airborne Hours Mininum Flight to Block Hours
1965 1970 1975 1980 1985 1990 1995 2000
Year
© 2003 Waitz 47
HISTORICAL TRENDSAerodynamic Efficiency
L/D
max
25
20
15
10
5
0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
abikian et al. (2002) Data Unavailable For: EMB-145 FH-227
BAE RJ85 SA-226
CV-600 DHC-7
Turboprops CV-880 Nihon YS-11
Regional Jets Beech 1900 DHC-8-100 Large Aircraft CV-580 L-188
DHC8-300
D328
J41
ATR42 BAE-ATP
ATR72F27 BAC111-200/400 B767-200/ER
S360
J31
SA227
S340A
F28-1000 F28-4000/6000
BAE146-100/200/RJ70 B727-200/231A BAE-146-300
B757-200 F100 B747-400 RJ200/ER B777
B707-100B/300 B707-300B B737-100/200 L1011-1/100/200
A300-600
DC9-30 B737-300
DC10-40
MD11
B737-400
A320-100/200A310-300
DC10-30 L1011-500 B767-300/ER
B747-100/200/300
DC10-10 MD80 & DC9-80 EMB120 B737-500/600
B
Year © 2003 Waitz 48
HISTORICAL TRENDSEngine Efficiency
TSFC
(mg/
Ns)
30
25
20
15
10
5
0
B707-300
B720-000
B727-200/231A
F28-4000/6000BAC111-400 DC9-40 BAE146-100/200/RJ70
CV880 F28-1000
BAE-146-300
F100 RJ85
B737-100/200DC9-30
DC9-10 DC9-50
MD80 & DC9-80
B737-300
D328 EM170
RJ200/ERF27
CV600
DC10-30
DC10-40
L1011-500
B767-200/ER MD11 B747-400
B737-400 B737-500/600
A300-600
B767-300/ER B757-200
L1011-1/100/200 B747-100
B747-200/300
DC10-10
EMB145
EMB135 RJ700
J31L188A-08/188C A320-100/200A310-300 B777
D328
J41
ATR72
DHC7 S360
B1900
CV580
SA226 SA227
EMB120 ATR42
DHC8-300BAE-ATP DHC8-100
DHC8-400
Turboprops
S340A
bikian et al. (2002)Ba
Regional Jets Large Jets New Regional Jet Engines New Turboprop Engines
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year
© 2003 Waitz 49
HISTORICAL TRENDSStructural Efficiency
OEW
/MTO
W
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
DC9-40
B737-100/200
B727-200/231A
DC9-10 DC10-10
BAC111-200 F28-1000
BAC111-400
F27 FH227
CV600
L188A-08/188C DC10-40
DC9-50
MD80 & DC9-80
B767-200/ER
B777B747-400
B737-400
B737-500/600
A320-100/200
A300-600 A310-300
B767-300/ER
B737-300 B757-200
L1011-1/100/200
B747-200/300
F28-4000/6000
BAE146-100/RJ70
BAE146-200
BAE-146-300 F100
RJ85
RJ200/ER
EMB145
DHC8-300D328
J41BAE-ATP
ATR72DHC7 S360
B1900
J31
DHC8-100
SA226
SA227 EMB120 S340A
ATR42
DC9-30CV880 L1011-500 DC10-30 MD11
B747-100
Turboprops
B707-300B
bikian et al. (2002)Ba
Regional Jets Large Aircraft
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Year
© 2003 Waitz 50
EFFICIENCYRegional Jets Versus Turboprops
6En
ergy
Usa
ge (M
J/A
SK)
5 Regional
BAC111-400 Jet Fleet Regional
4 CV880 Aircraft Fleet
BAC111-200
CV600
3 RJ200/ERB1900F28-1000 L188A-08/188C
BAE146-100 RJ85F28-4000/6000
F27 J31 DHC7
SA226 S360 SA227 BAE-146-300
F100 EMB1452 J41 D328Turboprop BAE146-200 DHC8-300Fleet
DHC8-100 ATR72S340ABabikian et al. (2002)
EMB120
1 ATR42 BAE-ATP
Turboprops Regional Jets
0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Year © 2003 Waitz 51
ENERGY USAGETotal Versus Cruise
0
1
2
3
4
5 M
J/A
SK
EU,CR Large Aircraft Total EU Large Aircraft EU,CR Regional Aircraft Total EU Regional Aircraft
Babikian (2001)
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
Year 52© 2003 Waitz
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 AIRCRAFTFacing Increasing Scrutiny
E U (M
J/A
SK)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
Jets Turboprops
Aircraft introduced during or after 1980 only
(Babikian, 2002)
0 1000 2000 3000 4000 5000 6000 7000 8000 9000
Stage Length (km)
Royal Commission on the Environment (2002)
the prospect of continuing rapid increases in air transport, particularly an increase in short haul flights…”
government should divert resources...encouraging and facilitating a modal shift from air to high-
“…deeply concerned at
“It is essential that the
speed rail.”
© 2003 Waitz 55
IMPACT OF NASA TECHNOLOGY SCENARIOSG
lob
al C
O2
Em
itte
d p
er Y
ear
Billion Kg Effect of Proposed Environmental CO2 Goals2000
1750
1500
1250
1000
750
500
250
0
1990 2000 2010 2020 2030 2040 2050
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
+340%
+140%
+230%
+40%
Change Relative to 1990:
Emission inventories
U.S. DOE reported fuel use
1990-5% Level
-20%
( - GA and Military Emissions based on Boeing forecast
- IPCC IS92a based ICAO demand model - No retrofit of technologies)
Kyoto Protocol Timing For Reductions
Year
J. E. Rohde, NASA 1999© 2003 Waitz 56
IMPACTS OF MISSION REQUIREMENTS (NOx & Noise)
• Range/payload ~ fuel efficiency (commercial and military) High pressures and– Thermal efficiency temperatures High NOx
– Propulsive efficiency velocity change Large mass flow with small
Low Noise
• Maneuverability (military) High energy conversion per
– High thrust-per-weight, unit volume (high small compact engine temperatures and
pressures) High NOx
• Supersonic flight (military) velocity change– Low drag, small compact
engine
Small mass flow with large High Noise
© 2003 Waitz 57
NOx EMISSIONS TECHNOLOGY TRENDS
© 2003 Waitz 58
NOx EMISSIONS TRENDS
© 2003 Waitz 59
HISTORICAL FLEET CRUISE EMISSIONS PERPASSENGER PER KILOMETER
1.0
Rel
ativ
e Em
issi
on /
Pass
-km
0.5
0
1975 1980 1985 1990 1995
NOx
CO2, H2O
CO
HC
Year (DuBois, Boeing)© 2003 Waitz 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 inAircraft Performance, Cost and Emissions,” Annual Review of Energy and theEnvironment, 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 onClimate Change (IPCC), Special Report on Aviation and the Global Atmosphere, 1999.
• RCEP, “The Environmental Effects of Civil Aircraft In Flight,” Royal Commission onEnvironmental Pollution (RCEP), England, December, 2003
© 2003 Waitz 63