Aircraft for Reduced Impact on Climate How Aircraft Design can Contribute to Mitigating Global Warming

Transcription

1 First CEAS European Air and Space Conference Berlin, September 2007 Aircraft for Reduced Impact on Climate How Aircraft Design can Contribute to Mitigating Global Warming Regina Egelhofer Technische Universität München

2 Acknowledgements To Gaby Rädel and Keith Shine (University of Reading) Marcus Köhler and Helen Rogers (University of Cambridge) Alain Joselzon (Airbus) Dan Allyn (Boeing) Paul Peeters (Breda University of Applied Sciences) for providing data and figures to the talk. 2

3 Airplane with minimum climate impact? Safe (parachute mandatory)? Comfortable? Fast? Independent of the weather? Can I put two suitcases in? Good service? Inexpensive? Can I go from Munich to Berlin? Photo credits: 3

4 Outline 1. Introduction 2. Aircraft emissions and their impact on climate 3. Mitigation options on the part of the airframe 4. Aircraft design methodology with full integration of climate impact 5. Conclusion 4

5 Introduction Definition of Environment linked to A/C operations Aviation Noise Emissions local local global Tradeoffs Tradeoffs Metrics? to enable Tradeoffs tradeoffs Community health Local air quality Climate change Environmental Impact Regulations, Charges, external costs 5

6 Introduction Regulatory constraints Development of emission regulations similar? What is the delay? Source: Boeing 6

7 Outline 1. Introduction 2. Aircraft emissions and their impact on climate 3. Mitigation options on the part of the airframe 4. Aircraft design methodology with full integration of climate impact 5. Conclusion 7

8 Aircraft emissions Relevant Emissions from Aviation 1 kg Fuel 3.4 kg O kg H 2 O 3.16 kg CO 2 Greenhouse gases In variable quantities: Nitrogen oxides NOx ~ 4-40g Sulphur oxides ~ 0.6-1g Particles / soot ~ g Contrails forms / depletes ozone O 3 depletes methane CH 4 Ozone and methane are greenhouse gases. 8

9 Climate Impact of Aviation Aircraft RF until 1992 / 2000 From Sausen et al in Meteorologische Zeitschrift, Vol. 14, Number 4,

10 Outline 1. Introduction 2. Aircraft emissions and their impact on climate 3. Mitigation options on the part of the airframe 4. Aircraft design methodology with full integration of climate impact 5. Conclusion 10

11 Simplified Aircraft Design Functional Chain 11

12 Manufacturers views (1): mitigation potentials Example of Aerodynamics Performance Improvement Winglets Design range +130 nautical miles Fuel burn -2.50% 500 nm mission -3.50% 1500 nm mission NOx Emissions -4.60% 1500 nm mission Payload at fixed range lb at fuel capacity limit lb at MTOW Airliners.net The improvement depends on the individual mission. Structural weight reductions referred to 1990 baseline: 8% until % until 2010 (A350 / 787 aircraft types) Future? From ICCAIA: The Manufacturers Perspectives, International Civil Aviation Day, 7 Dec. 2005, and ICAO Colloquium on Aviation Emissions, May

13 Manufacturers views (2): mitigation potentials Breakthroughs for fuel burn reduction are possible Aerodynamics: up to 10 % of fuel Advanced riblets Wave drag control Natural or hybrid laminar flow Innovative aircraft configuration Weights: up to 5% of fuel Next generation composite design and manufacturing Systems: 30% energy reduction of ECS identified by using low pressure bleed On-board systems optimisation offers an additional potential fuel burn benefit. 3% of fuel burn in cruise through fuel cells Changing cruise altitude Lowering cruise altitudes might help for NOx, but increases fuel burn up to +6% (for 4000ft cruise altitude reduction at M0.85) Better knowledge on contrails and cirrus needed to enable tradeoffs with fuel burn Biofuels, may become standard complement to oil kerosene. Summarised from Alain Garcia: Technical Press Briefing, Airbus, April 2007 Also in Aviation Week and Space Technology, August 20/27, p

14 Manufacturers views (3): mitigation potentials New technologies: Next generation composites Reducing pneumatic systems Biofuels with priority of BTL Airplane performance improvements (ongoing programs): Increased precision navigation for operational efficiency (737 NG) Lighter weight carbon brakes (737 NG) Blended winglets (737 NG): 3-5% aerodynamic efficiency / 2-4% in fuel burn Advanced wing design: raked wing tip, smaller wing vortex generators, revised ram air inlet for lower drag (777) Manoeuvre load alleviation for lower empty weight (777F) At least 15% improvement in fuel efficiency is required by the market in order to justify the development of a new generation of airplanes. Summarised from Boeing: Aviation and the Environment - Our Commitment to a Better Future, August

15 Alternative views (1) Increasing L/D Increase span. Wing weight - stronger lightweight materials, reduced Mach could compensate Radical solutions: Blended wing body Natural laminar flow control Hybrid laminar flow control (HLFC) Full (all-over) laminar flow control LFW with open rotor and 15% reduction in empty weight Blended Wing Body Laminar Flying Wing Also see: Aeronautical Journal, Aug 2006 Greener by Design, The Technology Challenge, 2001 Greener by Design, Mitigating the Environmental Impact of Aviation: Opportunities and Priorities, 2005 Increase from 15% to 65% in CFC structural component Tailplane, Fin, Nacelle Greener by Design From Prof. Jeff Jupp: The Impact of Aviation on the Environment How will the future for Air Transport be Affected? RAeS lecture at the Technical University of Munich, 14th of June

16 Alternative views (2) Peeters et al., TAC Conference 2006 Fuel efficiency is only one of many design requirements of commercial aircraft. From Greener by Design: Mitigating the Environmental Impact of Aviation: Opportunities and Priorities, Report

17 Outline 1. Introduction 2. Aircraft emissions and their impact on climate 3. Mitigation options on the part of the airframe 4. Aircraft design methodology with full integration of climate impact 5. Conclusion 17

18 What s the point? Fuel consumption depends on the mission (operations). And: Climate impact does not only depend on the quantities emitted, but also on where the gases occur. That s why we need to couple aircraft design with operations and we need an atmospheric / climate metric. 18

19 Distribution of aircraft emissions It is important, where the aircraft fly! Most important parameter: altitude Interdependence with classic aircraft design parameters Figure from DLR 19

20 Simplified Aircraft Design Functional Chain (2) Configuration Aircraft design today Structures Weights Lift Design Loop Aerodynamics Drag Thrust Noise Lift Drag Thrust Weight Aircraft design tomorrow Engine Technology Consumption Parameter? Emissions Atm. Impact 20

21 Design approach including global warming Aicraft Design / Perf. ALT Climate impact eval. Holistic approach at system level Credits: Eurocontrol Operations Climate Impact Emission scenarios Impact-driven instead of emissions-driven design! 21

22 Example 1: Benefit of fleet renewal Virtual scenario: 2005 traffic, 1995-type fleet Only routes that existed in both years (OAG) Operations included 1995 Reference 2005 Reference 2005 Virtual Delta Available Seat Kilometres (ASK) [10 12 ] % Estimated Load Factor [-] 69% 75% 75% Total flown distance from OAG [10 9 km] Considered number of flights in OAG [million] Total flown distance calculated [10 9 km] % Fuel consumption [Tg] % NOx emissions [Tg] % Global NOx emissions index [g/kg] % Average seat capacity [-] Average sector length [km] Consumption/100ASK [kg] Consumption/100RPK [kg] Consumption/100RPK [l] % Detailed results in Egelhofer et al., 2007, Journal of Air Transportation, Vol. 12, No. 2, in print. 22

23 Atmospheric evaluation: LEEA project (1) LEEA: Low Emissions Effect Aircraft. Project sponsored by DTI (UK) and Airbus 15km Complicated processes in the atmosphere ALTITUDE Simple atmospheric metrics (Kyoto GWP) not sufficient to represent aviation s climate impact. 5km From: Köhler et al., TAC Conference 2006, Oxford 23

24 Atmospheric evaluation: LEEA project (2) LEEA: Low Emissions Effect Aircraft. Project sponsored by DTI (UK) and Airbus Ozone forcing per TgN (ALT) Only ozone forcing, methane effect not included! From: Rädel and Shine, TAC Conference 2006, Oxford 24

25 Example 2: Climate impact of combustor techn. Climate metric included Climate impact ratio (based on LEEA): Low Nox Combustor Impact Standard Combustor Impact * 2000 nm Flight altitude Distance Fuel burn Climate impact ratio Taxi and Takeoff 750 0% 3% 1 Climb % 14% 1.20 Step % 13% 0.96 Step % 63% 0.95 Step % 3% 0.94 Descent % 2% 1.01 Landing and Taxi 750 0% 2% 1 Total 100% 100% 0.96 * technology level: Double annular combustor./. single annular combustor More details in: Egelhofer et al., published at SAE AeroTech 2007 Conference, paper

26 Drawbacks and open questions Complexity: Data management and uncertainties Lack of appropriate / reliable metrics at several levels Which metrics could allow tradeoffs to non-environmental issues (monetary / regulations)? Competences within industry (atmospheric sciences)? Competences within sciences (aircraft design and operations)? Continue existing and create new research cooperation 26

27 Outline 1. Introduction 2. Aircraft emissions and their impact on climate 3. Mitigation options on the part of the airframe 4. Aircraft design methodology with full integration of climate impact 5. Conclusion 27

28 Airplane with minimum climate impact? Aircraft Design We should re-open the design space: Design Range? Speed? Cruise altitude? of today s aircraft are no premises. from John P. Fielding: Introduction to Aircraft Design 28

29 Conclusion Rebalancing the importance of the atmosphere presumes reliable metrics (need for development / improvement / validation). Engineering shall keep the pace of atmospheric scientists in order to be able to integrate new knowledge as quickly as possible. Any financial penalties and restriction systems have to be coherent and goal-orientated. All stakeholders of the air transport system must work hand in hand (systems approach). The early consideration of the environment in aircraft design will be vital for the manufacturer, once regulations represent the actual impact. Anticipating political conditions and designing respective aircraft will then provide an economic asset and competitive advantage for the aircraft manufacturer. The social acceptance of aviation could increase, if advances are appropriately communicated (!). Aviation should not be afraid of new environmental regulations, but take advantage of them as drivers for innovation. Let s go back to work! 29

30 Thank you for your attention! References Advisory Council for Aeronautics Research in Europe, Strategic Research Agenda 2 (SRA2), 2004, available on Berntsen, T.K., J.S. Fuglestvedt, M.M. Joshi, K.P. Shine, N. Stuber, M. Ponater, R. Sausen, D.A. Hauglustaine, L. Li, Response of climate to regional emissions of ozone precursors: sensitivities and warming potentials, Tellus, 57B, , Egelhofer, R., C. Bickerstaff and S. Bonnet, Minimizing Impact on Climate in Aircraft Design, SAE AeroTech 2007 Conference and Exhibition, Los Angeles, Sept Egelhofer, R., C. Marizy and C. Cros, Climate Impact of Aircraft Technology and Design Changes, Journal of Air Transportation, Vol. 12, No. 2, in print, Eyers, C. J., P. Norman, J. Middle, M. Plohr, S. Michot, K. Atkinson, R.A. Christou, AERO2K Global aviation emissions inventories for 2002 and 2025, Final report, EC project G4RD-CT , Garcia, A., Airbus Holistic Roadmap to the Future, Airbus Technical Press Briefing, April Greener by Design, Air Travel Greener by Design, The Technology Challenge, Royal Aeronautical Society, Greener by Design, Mitigating the Environmental Impact of Aviation: Opportunities and Priorities, Royal Aeronautical Society, Intergovernmental Panel on Climate Change (IPCC), Aviation and the Global Atmosphere, Special Report of IPCC Working Groups I and III, J.E. Penner et al. (Eds.), Cambridge University Press, Cambridge, Intergovernmental Panel on Climate Change (IPCC), Working Group I: The physical basis of Climate Change, Fourth Assessment Report of the IPCC, 2007, available on International Coordinating Council of Aerospace Industries Associations, Reducing Aviation Emissions The Manufacturers Perspective, International Civil Aviation Day, 7 December Joselzon, A., Fuel Conservation A manufacturer s perspective, ICAO Colloquium on Aviation Emissions with Exhibition, May Jupp, J., The Impact of Aviation on the Environment - How will the future for Air Transport be Affected?, Lecture at Forum der Luft- und Raumfahrt, Technische Universität München, June Köhler, M., O. Dessens, O. Wild, H. Rogers, J. Pyle, Changes in Ozone and Methane due to Aircraft NOx: Sensitivity to Cruise Altitude, International Conference on Transport, Atmosphere and Climate (TAC), Oxford, Great Britain, 2006, Proceedings in print. Rädel, G., K. Shine, Sensitivity of Radiative Forcing due to Aircraft Altitude, International Conference on Transport, Atmosphere and Climate (TAC), Oxford, Great Britain, 2006, Proceedings in print. Sausen, R., I. Isaksen, V. Grewe, D. Hauglustaine, D. S. Lee, G. Myhre, M. O. Köhler, G. Pitari, U. Schumann, F. Stordal, C. Zerefos, Aviation radiative forcing in 2000: An update in IPCC (1999), Meteorologische Zeitschrift, 14, , Schumann, U., Aircraft Emissions, In: I. Douglas (Ed.), Encyclopedia of Global Environmental Change, John Wiley & Sons, Ltd, Chichester, 2002, pp Shine, K.P., J.S. Fuglestvedt, K. Hailemariam, N. Stuber, Alternatives to the Global Warming Potential for comparing climate impacts of emissions of greenhouse gases, Climatic Change, 68, ,