EC Tier 1 uncertainty analysis Uncertainty workshop Bernd Gugele, ETC-ACC 5 September 2005

2 Availability of Table 6.1 of the Tier 1 uncertainty analysis as of 15 April 2005 Member StateYearCoverageMember StateYearCoverage Austria200396%Ireland % Belgium200199%Italy % Denmark200292%Netherlands % Finland200297%Spain % France %Sweden % Germany %United Kingdom % Greece % For 13 MS Tier 1 uncertainty estimates available Four MS 2003, eight MS 2002, one MS 2001 Most MS cover all source categories (except for LUCF) 95 % of total EU-15 GHG emissions in 2003 are covered

3 Uncertainty analysis: approach (1) MS uncertainty estimates were grouped by source categories Level of detail varies between MS –1A (stationary), 1A1 or 1A1a –split by fuels or not –2001/2002 used because more detailed fuel split

4 Uncertainty analysis: approach (2)

5 Uncertainty analysis: approach (3) Then for each source category a range of uncertainty estimates was calculated: –lower bound: assuming no correlation among MS uncertainty estimates –upper bound: assuming full correlation among MS uncertainty estimates Basic equations on summing up of variances with correlation: –VAR(X+Y)=VAR(X)+VAR(Y)+2COVAR(X,Y) –COVAR(X,Y)=r*sqrt[VAR(X)*VAR(Y)] –VAR: variance –COVAR: covariance –R: correlation coefficient (assumed to be 1)

6 Uncertainty analysis: approach (4) Then single uncertainty estimate calculated for each source category assuming that: –MS uncertainty estimates fully correlate if default EF are used and/or Tier 1 methods are used –The fact that AD are most likely uncorrelated was neglected Then uncertainty estimates for total GHG emissions and for the sectors were calculated: –Stationary fuel combustion –Transport –Fugitive emissions –Industrial processes –Agriculture –Waste Also plausibility checks were made with Monte Carlo tool

7 Uncertainty analysis: example Emissions of four member states are considered to be correlated, because they use the same, default EF Uncertainty EU-15 = 13.3 % CO 2 emissions from 2 A 2 Lime Production MS uncertainties range from 5 % – 30 % Four MS use the same, default emission factors (DE, GR, SE, UK)

8 EU-15 uncertainty estimates Lowest uncertainty estimates for stationary fuel combustion (1 %) and transport (3 %) Highest estimates for agriculture (44 % - 83 %). For agriculture the range depends on assumption on N2O emissions from soils: –lower bound: not correlated –upper bound: fully correlated

9 Uncertainty estimates and recalculations

10 Uncertainty contribution 15 sources contribute 99.7% to EC uncertainties

11 Uncertainty estimates: 4D N 2 O EC range: 89% - 233%

12 Uncertainty estimates: 1A3b CO 2 EC range: 3.4% - 7.4%; EC estimate: 3.4%

13 Uncertainty estimates: 4B N 2 O EC range: 50% - 133%; EC estimate: 109%

14 Uncertainty estimates: 4B CH 4 EC range: 33% - 69%; EC estimate: 33%

15 Uncertainty estimates: 1A1a CO 2 EC range: 3.1% - 5.0%; EC estimate: 3.1%

16 Issues for Working group Level of detail of EC uncertainty analysis –Currently detailed level depending on MS availability –Combination of different levels (e.g. 1A1-1A1a; 1A) appropriate? Methods/assumptions to combine uncertainty estimates at EC level –Criteria to identify correlations? –Currently: focus on EF and methods; neglect AD –Is assumption on full correlation appropriate? Improvement of EC uncertainty analysis –Combination of various years: alternative? –Not for all MS/sectors (i.p. LULUCF) available: gap filling? –How to estimate trend uncertainty? No AD, EF uncertainty for EC –Correction for large uncertainties? Tier 2 approach? Timing of EC uncertainty analysis –How often and when –Use of EC uncertainty estimates e.g. Tier 2 Key source analysis

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18 Uncertainty 1A4b CO 2 EC range: 3.2% - 7.0%; EC estimate: 3.3%