1. Approaches for separating domestic and international aviation emissions Odette Deuber Technical workshop on emissions from aviation and maritime transport Oslo, 4.-5. October 2007

2. Overview Background Reporting guidelines Methods applied in Annex I Countries Use of databases on PKM and TKM Conclusions

3. Background Bunker fuel do not fall under binding targets of the Kyoto Protocol, thus necessity of splitting fuel consumption by aviation into dom. and int. shares. Reporting guidelines for and definitions of emissions from domestic and international aviation: IPCC Guidelines, Good Practice Guidance. Methods for separating activity data for dom. and int. aviation are country-specific. Methodologies and assumptions must be described in detail in the National Inventory Reports.

4. Good Practice Guidance 2000 2006: Tier 1: Fuel based approach Tier 2: Based on fuel use and number of LTO cycles a) aggregated level of all aircrafts b) level of individual aircrafts - preferably Tier 3: Methods using flight movement data 3 A: based on origin and destination data 3 B: based on full trajectory flight

5. Assessment of National Inventory Reports 2007 Tier 1: Bulgaria, Belarus, Canada (modified), Croatia, Czech Republic, Estonia, Germany, Greece, Hungary, Iceland, Lithuania, Latvia, Luxembourg, New Zealand, Poland, Romania, Russian Federation, Slovakia, Slovenia, Turkey, Ukraine, USA Tier 2: Australia, Belgium, Ireland, Italy (a), Japan, Netherlands, Norway, Portugal (a), Spain, Sweden (a) Tier 3: Austria, Denmark, Finland, France, Switzerland, United Kingdom

6. Top Down Approaches Energy Statistics Estonia, (Ireland), Poland, Austria Taxation/custom authorities, Fuel expenditures Australia (int), Japan (int), USA (foreign flagged) Fuel suppliers/Fuel sales Iceland, New Zealand, Finland (int), Spain

7. Bottom-up Approaches/ Models Survey of airline companies, aircraft movement data, statistical offices or statistics from transport ministries, Airport records Norway, France (dom), USA (US flag carrier), Italy (LTO), Portugal, Sweden, Netherlands (precursor), Belgium, Ireland Austria (until 2000 MEET, since 2001 dom./int. LTO), Denmark, United Kingdom, Switzerland (FOCA), Finland (ILMI) Data on tonne-km Canada (dom airlines dom-int) Other origin- destination data, Air carrier schedules, Air traffic control records, full trajectory models ANCAT3, Official Airline Guide (Future Aviation Scenario Tool FAST), SAGE, Aviation Emission Model (AEM)

8. Other Approaches Expert Judgement Bulgaria (20%/80%); Romania (20%/80%); Ukraine (country comparison 6%/94%) Research Projects Germany (20%/80%), Latvia (dom. emissions), Netherlands (dom. CO 2 ) Small country approach: gasoline = dom, jet fuel = int. Lithuania, Belgium, Slovenia, Hungary

9. Summary A variety of methods are applied to separate dom. from int. aviation emissions. Often different approaches are combined, usually bottom up calculations are adjusted to energy statistics. In less developed approaches it is difficult to map variations in the split over time. If energy statistics provide a reliable split, acceptable results can be obtained without higher tiers (bottom-up approaches). Countries with Tier 2 and 3 usually have more detailed data on the split of dom – int LTO cycles. Countries with Tier 3 use generally detailed air movement data for the spilt. Comparison of model results and national approaches is worthwile.

10. Separating emissions from dom. and int. aviation on the basis of TKM Statistics? Could statistics on Freight- and Passenger-KM be used to check consistency of splits calculated (dom-int) on the basis of other approaches? as proxy for fuel consumption? ICAO Database: dom. and int. passenger and freight transport data (PKM dom, PKM int, TKM dom, TKM int ) Complete time series 1990 – 2004 For rough estimates used here: 1990, 1995, 2000, 2003 Flag-based data – fuel sale data

11. Method to check the applied split between domestic and international aviation emission PKMTKM TKM total CO 2 Assumption: 1 PKM = 0,15 TKM Flag-based -> Fuel sale data Dom. Emissions: share of dom. TKM flown by domestic/foreign flag based carriers Int. Emissions: share of int. TKM by all carriers arriving/departing in one country and share of domestically purchased fuel for these flights CO 2 /TKM total UNFCCC ICAO CO 2 intensity depends on: Distances of flights Aircraft fleet: age and composition Emission reductions measures

12. CO 2 Intensities of domestic aviation emissions: Annex I Countries - Outlier Czech Republic Bulgaria Ireland

13. CO 2 Intensities in dom. Aviation (Annex I Countries)

14. CO 2 Intensities in int. Aviation (Annex I Countries)

15. CO 2 Intensities of selected countries Austria dom T3 Denmark dom T3 Greece dom T1 Lufthansa fleet average (2006): 0,5 kg CO 2 /TKM regional flights (2006): 1 kg CO 2 /TKM

16. CO 2 Intensities of selected countries Austria dom Austria int Denmark int Denmark dom Greece dom Greece int Lufthansa fleet average (2006): 0,5 kg CO 2 /TKM regional flights (2006): 1 kg CO 2 /TKM

17. CO 2 Intensities in Aviation (Tier 3) Denmark international domestic Denmark Austria

18. Method to estimate emissions? PKMTKM TKM total CO 2 /TKM Assumption: 1 PKM = 0,15 TKM CO 2 ICAO Data on CO 2 intensity available for domestic oder international flights? Default CO 2 intensity cannot be given as there are a variety of influencing factors.

19. Case Study: Canadas method to split fuel sold to dom. carriers into dom. and int. activity Fuel sold to national carriers TKM dom Fuel dom Flag Fuel-based approach Assumption: share of int. TKM which are flown by domestically purchased fuel (69%/31%) Fuel int CO 2int TKM int Split: dom – int Fuel sold to foreign carriers In excellent agreement with SAGE and AERO2K

20. Conclusions Using TKM statistics can be worthwhile for checking the split of dom. and int. aviation emissions If dom. and int. CO 2 intensities fluctuate strongly from year to year and fluctuate in opposite signs -> check split. Final conclusion on CO 2 intensities only on the basis of complete time series and country details. Level of CO 2 intensity compared with other countries might give a hint on quality of separation method. TKM is not per se a proxy for fuel consumption. Conversion of flag-based into fuel sale-based data usually easier for domestic aviation. There are cases in which also int. aviation emissions can be obtained by this approach.

21. Very Last Conclusion… Let us be creative to find further methods for separating domestic and international emissions!

22. TKM – A proxy for CO 2 Emission? All Annex I Countries (without US), 2000, CO 2 (based on inventory), Domestic

23. Average fuel use per pkm for flights of varying lengths Source: RCEP 2002 LTO cycle Fuel transport