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 (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 CO 2 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/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 VLD ( ) = ln + g SFC 1 W fuel W + W + W payload structure reserve = Technology = Operations W Efficiency ASK kg fuel payload W f g StageLength, W fuel Stagelength # seats = Use data to separate effects and understand influences of technology 2003 Waitz 45
TRENDS IN LOAD FACTOR 0.8 0.7 0.6 Regional Jets Large Aircraft Load Factor 0.5 0.4 0.3 Turboprops 0.2 0.1 0.0 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 DELAYS 1.0 0.9 0.8 0.7 Ratio 0.6 0.5 0.4 0.3 0.2 0.1 Airborne to Block Hours Minimum Flight to Airborne Hours Mininum Flight to Block Hours 0.0 1965 1970 1975 1980 1985 1990 1995 2000 Year 2003 Waitz 47
25 HISTORICAL TRENDS Aerodynamic Efficiency F28-1000 F28-4000/6000 L/Dmax 20 15 10 F27 B707-100B/300 S360 A320-100/200 A310-300 RJ200/ER B757-200 B747-400 B747-100/200/300 F100 BAC111-200/400 B767-200/ER ATR72 S340A MD11 DC10-30 L1011-500 B767-300/ER B707-300B ATR42 BAE-ATP B737-100/200 A300-600 L1011-1/100/200 D328 DC9-30 B737-300 DC10-10 MD80 & DC9-80 EMB120 B737-500/600 DC10-40 B737-400 BAE146-100/200/RJ70 B727-200/231A BAE-146-300 SA227 J41 J31 B777 DHC8-300 5 Babikian et al. (2002) Data Unavailable For: EMB-145 FH-227 CV-880 Nihon YS-11 BAE RJ85 SA-226 Turboprops Regional Jets Beech 1900 DHC-8-100 Large Aircraft CV-580 L-188 CV-600 DHC-7 0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Year 2003 Waitz 48
30 HISTORICAL TRENDS Engine Efficiency B707-300 B720-000 25 B727-200/231A TSFC (mg/ns) 20 15 BAC111-400 DC9-40 F28-4000/6000 BAE146-100/200/RJ70 CV880 DC9-10 F28-1000 DC9-50 B737-300 DC9-30 B737-100/200 BAE-146-300 MD80 & DC9-80 F100 RJ85 D328 EM170 DC10-30 L1011-500 B767-300/ER EMB145 B737-400 B737-500/600 B747-100 F27 B747-200/300 B757-200 RJ200/ER RJ700 L1011-1/100/200 B747-400 CV600 DC10-40 B767-200/ER EMB135 MD11 DC10-10 A300-600 L188A-08/188C J31 A310-300 A320-100/200 B777 CV580 SA226 B1900 SA227 DHC7 J41 S360 EMB120 ATR42 ATR72 D328 DHC8-100 BAE-ATP DHC8-300 DHC8-400 S340A 10 Babikian et al. (2002) 5 Turboprops Regional Jets Large Jets New Regional Jet Engines New Turboprop Engines 0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year 2003 Waitz 49
OEW/ MTOW 0.70 0.60 0.50 0.40 0.30 F27 L188A-08/188C HISTORICAL TRENDS Structural Efficiency B727-200/231A CV600 F28-1000 BAC111-200 BAC111-400 DC9-10 FH227 DC10-10 B737-100/200 DC9-40 SA226 BAE146-200 MD80 & DC9-80 L1011-1/100/200 F28-4000/6000 B767-200/ER B747-200/300 DC10-40 DHC7 DC9-50 S360 BAE146-100/RJ70 CV880 L1011-500 DC9-30 DC10-30 B747-100 B707-300B DHC8-100 J31 SA227 ATR42 B1900 F100 B737-300 B757-200 EMB120 S340A A300-600 A310-300 B767-300/ER BAE-ATP ATR72 J41 BAE-146-300 A320-100/200 B737-400 B737-500/600 B747-400 MD11 D328 RJ85 RJ200/ER B777 DHC8-300 EMB145 0.20 0.10 Babikian et al. (2002) Turboprops Regional Jets Large Aircraft 0.00 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Year 2003 Waitz 50
6 EFFICIENCY Regional Jets Versus Turboprops Energy Usage (MJ/ASK) 5 Regional BAC111-400 Jet Fleet Regional CV880 4 Aircraft Fleet BAC111-200 CV600 F28-1000 B1900 RJ200/ER 3 L188A-08/188C BAE146-100 RJ85 F28-4000/6000 F27 SA226 DHC7 J31 S360 SA227 BAE-146-300 F100 2 J41 D328 Turboprop Fleet Babikian et al. (2002) BAE146-200 DHC8-100 S340A EMB120 1 ATR42 BAE-ATP Turboprops Regional Jets 0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year 2003 Waitz 51 DHC8-300 ATR72 EMB145
5 4 3 ENERGY USAGE Total Versus Cruise Babikian (2001) E U,CR Large Aircraft Total E U Large Aircraft E U,CR Regional Aircraft Total E U Regional Aircraft MJ/ASK 2 1 2003 Waitz 0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Year 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 E U (MJ/ASK) 3.5 3.0 2.5 2.0 1.5 Jets Turboprops (Babikian, 2002) 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 1.0 0.5 0 Aircraft introduced during or after 1980 only 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 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 Global CO 2 Emitted per Year Billion Kg 2000 1750 1500 1250 1000 750 500 Effect of Proposed Environmental CO 2 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 ( - GA and Military Emissions based on Boeing forecast - IPCC IS92a based ICAO demand model - No retrofit of technologies) U.S. DOE reported fuel use 1990-5% Level Change Relative to 1990: +340% +230% +140% 250 Kyoto Protocol -20% Emission inventories Timing For Reductions 0 1990 2000 2010 2020 2030 2040 2050 Year +40% 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 High NO temperatures x Propulsive efficiency Large mass flow with small velocity change Low Noise Maneuverability (military) High energy conversion per High thrust-per-weight, unit volume (high small compact engine temperatures and pressures) High NO x Supersonic flight (military) Low drag, small compact engine Small mass flow with large velocity change High Noise 2003 Waitz 57
NO x EMISSIONS TECHNOLOGY TRENDS 2003 Waitz 58
NO x EMISSIONS TRENDS 2003 Waitz 59
HISTORICAL FLEET CRUISE EMISSIONS PER PASSENGER PER KILOMETER 1.0 NO x Relative Emission / Pass-km 0.5 CO 2, H 2 O CO HC 0 1975 1980 1985 1990 1995 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 NO x 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