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IPCC Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories UNFCCC Workshop on the Preparation of National Communications from non-Annex I Parties April 26 -30, 2004, Manila Leandro Buendia Programme Officer, IPCC-NGGIP-TSU ([email protected] or. jp)
Decision 17/CP. 8, Annex (Guidelines for the Preparation of NC from non-Annex 1 Parties) Objectives Para 1 b. To encourage the presentation of information in a consistent, transparent and comparable, as well as flexible, manner, taking into account specific national circumstances.
Decision 17/CP. 8 Methodologies Para 11. Non-Annex 1 Parties are encouraged to apply the IPCC Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories, taking into account the need to improve transparency, consistency, comparability, completeness and accuracy in inventories. Para 12. Non-Annex I Parties are also encouraged, to the extent possible, to undertake any key source analysis as indicated in the IPCC good practice guidance to assist in developing inventories that better reflect their national circumstances.
Decision 17/CP. 8 Reporting Para 24. Non-Annex I Parties are encouraged to provide information on the level of uncertainty associated with inventory data and their underlying assumptions, and to describe the methodologies used, if any, for estimating these uncertainties.
Contents Background Information What is good practice guidance Contents of the Report Key Source Category Policy Relevance Conclusion
Background Information June 1998: SBSTA 8 encouraged IPCC to give high priority to completing its work on uncertainty, as well as to prepare a report on good practices in inventory management and to submit a report on these issues for consideration by SBSTA, if possible by COP 5 October 1998: IPCC held a Planning Meeting in Paris to plan for the work January 1999 – October 1999: Sectoral and Cross-sectoral Expert Meetings December 1999 - February 2000: First draft was reviewed by governments and experts May 2000: IPCC XVI accepted the GPG 2000 Report June 2000: SBSTA 12 endorsed the GPG 2000
Background Information IPCC Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories (GPG 2000) Published in 2000
What is good practice guidance? Good Practice Guidance (GPG) aims to assist countries in producing inventories: üthat are neither over- nor underestimates so far as can be judged üin which uncertainties are reduced as far as is practicable
Further aims, to produce inventories which are: ü ü ü ü transparent documented consistent over time complete comparable assessed for uncertainties subject to quality control and assurance efficient in the use of resources
Structure of the GPG 2000 Preface Chapter 1 Introduction Chapter 2 Energy Source category good Chapter 3 Industrial Processes practice guidance Chapter 4 Agriculture Chapter 5 Waste Chapter 6 Quantifying Uncertainties in Practice Chapter 7 Methodological Choice and Recalculation Chapter 8 Quality Assurance and Quality Control Annex 1 Conceptual Basis for Uncertainty Analysis Annex 2 Verification Annex 3 Glossary Annex 4 List of Participants
Source category specific good practice guidance (Chapters 2 to 5) 1. Methodological Issues ü Choice of method ü Choice of emission factors ü Choice of activity 2. 3. 4. 5. 6. Completeness Developing a Consistent Time series Uncertainty Assessment Reporting and Documentation Inventory Quality Assurance/Quality Control
1. Methodological Issues Ø Choice of Method ü estimation methods suited to national circumstances ü decision trees (which tier? ) Ø Choice of Emission Factors ü most suitable emission factors for inventory calculation (default values) Ø Choice of Activity Data ü most suitable activity data for inventory calculation
Figure 4. 2 Decision Tree for CH 4 Emissions from Enteric Fermentation Does the country manage cattle, buffalo, sheep, goats, camels, mules/asses, swine, or other livestock? No Report ‘Not Occurring’ Yes Is enteric fermentation a key source category? (Note 1) No Yes Ask for each species: Is this sub-source category significant? (Note 2) Yes Estimate emissions for the species using Tier 2 No Ask for each species: Are data available with which to perform a Tier 2 estimate? No Yes Estimate emissions for the species using Tier 1
2. Completeness Ø advice to ensure complete estimates 3. Developing a Consistent Time series Ø advice to ensure consistency throughout the time series 4. Uncertainty Assessment Ø provide default values for uncertainty ranges
5. Reporting and Documentation Ø provide what information is necessary for the specific source category 6. Inventory Quality Assurance/Quality Control Ø guidance and procedures to enable cross -checks during inventory compilations
Chapter 6: Quantifying Uncertainties in Practice Ø describes GPG in estimating and reporting uncertainties associated with both annual estimates emissions Ø identifies types of uncertainty from the viewpoint of the inventory practitioner and shows how to obtain expert judgment in a consistent manner Ø provides two tiers for combining source category uncertainties into an uncertainty estimate for total national emissions
Chapter 7: Methodological Choice and Recalculation Ø how to identify key source categories in the national inventory Ø how to systematically manage methodological change overtime and ensure that trends in national emissions are consistently estimated
Chapter 8 Quality Assurance and Quality Control Ø covers measurement standards, routine computational and completeness checks, and documentation and data archiving procedures to be applied to the inventory at the compilation stage. Ø describes a system of independent review and auditing that could be implemented by inventory agencies Ø covers only actions that inventory agencies could take in respect of their own inventories
Annex 1 Conceptual Basis for Uncertainty Analysis Ø deals with the concepts that underlie the practical advice on uncertainties provided in the Chapters 2 to 8 of the main report (statistical concepts, sources of uncertainties, applications)
Annex 2 Verification Ø discusses international and scientific aspects, options or tools for inventory verification Ø includes practical guidance for verification of emissions inventories
Annex 3 Glossary Ø defines the terms of particular interest in the context of greenhouse gas inventories Ø summarises mathematical definitions of selected statistical terms for convenient reference
Key Source Category “A key source category is one that is prioritized within the national inventory system because its estimate has a significant influence on a country’s total inventory of direct greenhouse gases in terms of the absolute level of emissions, the trend in emissions, or both. ”
Why do we need to identify key source categories in the national inventory? Ø inventory development is a resource intensive enterprise Ø in most cases, resources are limited and have to be prioritized Ø certain source categories are particularly significant in their contribution to the overall uncertainty of the inventory
“It is important to identify these key source categories so that the resources available for inventory preparation may be prioritized and the best possible estimates prepared for the most significant source categories. ” …How do we identify Key Source Categories?
Key Source Category Analysis Ø Quantitative Approach – relationship between the level and trend of each source category’s emissions and total national emissions (Level and Trend Assessments) Ø Qualitative Approach – considers other criteria that are not easily assessed through a quantitative analysis.
Decision tree to identify key source categories Are inventory data available for more than one year? No Determine key categories using the Tier 1 Level Assessment and evaluating qualitative considerations Yes Are country-specific uncertainty estimates available for each category estimate? Yes Determine key categories using the Tier 2 Level and Trend Assessments, incorporating national uncertainty estimates and evaluating qualitative criteria No Determine key categories using the Tier 1 Level and Trend Assessments and evaluating qualitative criteria
Quantitative Approach -Tier 1 Method Level Assessment Equation 7. 1 Source Category Level Assessment = Source Category Estimate / Total Estimate Lx, t = Ex, t / Et Where: Lx, t is the Level Assessment for source x in year t Source Category Estimate (Ex, t ) is the emission estimate of source category x in year t Total Estimate (Et) is the total inventory estimate in year t
Table 7. 2: Spreadsheet for the Tier 1 Analysis – Level Assessment Column A – list of IPCC source categories (see Table 7. 1, Suggested IPCC Source Categories) Column B – Direct Greenhouse Gas ( CO 2, CH 4, N 2 O, etc. ) Column C – Base year emissions estimates from the national inventory data, in CO 2 -equivalent units Column D – Current year emissions estimates from the most recent national inventory, in CO 2 -equivalent units Column E: Level Assessment from Equation 7. 1 Column F: Cumulative total of Column E
How to decide using Table 7. 2? Any source category that meets the 95% threshold in any year should be identified as a key source category.
Tier 1 Analysis – Level Assessment (US Inventory) IPCC Source Categories Direct Greenhouse Gas Level Assessment Cumulative Total of LA CO 2 Emissions from Stationary Combustion Coal CO 2 481. 6 533. 3 0. 29 Mobile Combustion – Road & Other CO 2 338. 1 381. 0 0. 21 0. 50 CO 2 Emissions from Stationary Combustion Gas CO 2 266. 0 313. 1 0. 17 0. 68 CO 2 Emissions from Stationary Combustion – Oil CO 2 176. 8 177. 5 0. 10 0. 77 CH 4 Emissions from Solid Waste Disposal Sites CH 4 56. 2 66. 7 0. 04 0. 81 Direct N 2 O Emissions from Agricultural Soils N 2 O 46. 6 53. 7 0. 03 0. 84 Mobile Combustion: Aircraft CO 2 50. 5 50. 1 0. 03 0. 87 34. 5 35. 1 0. 02 0. 89 Fugitive Emissions from Oil and Gas Operations Base Year Estimate Current Year Estimate CH 4 Emissions from Enteric Fermentation in Domestic Livestock CH 4 32. 7 34. 1 0. 02 0. 91 Indirect N 2 O Emissions from Nitrogen Used in Agriculture N 2 O 18. 8 20. 4 0. 01 0. 92 Fugitive Emissions from coal mining and handling CH 4 24. 0 18. 8 0. 01 0. 93 CH 4 Emissions from Manure management CH 4 14. 9 17. 0 0. 01 0. 94 Mobile Combustion: Road and Other N 2 O 13. 0 16. 9 0. 01 0. 95 Mobile Combustion: Marine CO 2 16. 4 15. 4 0. 01 0. 96 …… …… …… 1632. 1 1813. 6 1. 00 TOTAL
Tier 1 Method Trend Assessment Equation 7. 2 Source Category Trend Assessment = (Source Category Level Assessment) x (Source Category Trend –Total Trend) Tx, t = Lx, t * [( Ex, t - Ex, o) / Ex, t] - [(Et - Eo)/ Et] Where: Tx, t is the Trend Assessment which is the contribution of the source category to the overall inventory trend (absolute value) Lx, t is the Level Assessment for source x in year t (Equation 7. 1) Ex, t and Ex, o are the emissions estimates of source category x in years t and 0, respectively Et and Eo are the total inventory estimates in years t and 0, respectively
Table 7. 3: Spreadsheet for the Tier 1 Analysis – Trend Assessment Column A – list of IPCC source categories (see Table 7. 1, Suggested IPCC Source Categories) Column B – Direct Greenhouse Gas ( CO 2, CH 4, N 2 O, etc. ) Column C – Base year emissions estimates from the national inventory data, in CO 2 -equivalent units Column D – Current year emissions estimates from the most recent national inventory, in CO 2 -equivalent units Column E: Trend Assessment from Equation 7. 2 recorded as an absolute number Column F: Percentage contribution to the total trend of the national inventory Column G: Cumulative Total of Column F
Tier 1 Analysis – Trend Assessment (US Inventory) IPCC Source Categories Direct Greenhouse Gas Base Year Estimate Current Year Estimate Trend Assessment % Contribution to trend Cumulative Total CO 2 Emissions from Stationary Combustion - Oil CO 2 176. 8 177. 5 0. 01 19 0. 19 CO 2 Emissions from Stationary Combustion - Gas CO 2 266. 0 313. 1 0. 01 17 0. 36 Several 0. 3 14. 7 0. 01 14 0. 50 Fugitive Emissions from Coal Mining & handling CH 4 24. 0 18. 8 <0. 01 8 0. 58 Mobile Combustion: Aviation CO 2 50. 5 50. 1 <0. 01 6 0. 64 Mobile Combustion: Road & Other CO 2 338. 1 381. 0 <0. 01 5 0. 69 CH 4 Emissions from Solid Waste Disposal Sites CH 4 56. 2 66. 7 <0. 01 4 0. 73 Fugitive Emissions from Oil & Gas Operations CH 4 34. 5 35. 1 <0. 01 3 0. 76 Mobile Combustion: Marine CO 2 16. 4 15. 4 <0. 01 3 0. 79 PFC Emissions from Aluminum Production PFC 4. 9 2. 9 <0. 01 3 0. 82 Mobile Combustion: Road & Other N 2 O 13. 0 16. 9 <0. 01 2 0. 84 HFC-23 Emissions from HCFC-22 Manufacture HFC 9. 5 8. 2 <0. 01 2 0. 87 CH 4 Emissions from Enteric Fermentation in Livestock CH 4 32. 7 34. 1 <0. 01 2 0. 89 Direct N 2 O Emissions from Agricultural Soils N 2 O 46. 6 53. 7 <0. 01 2 0. 91 CO 2 Emissions from Stationary Combustion – Coal CO 2 481. 6 533. 3 <0. 01 2 0. 92 N 2 O Emissions from Adipic Acid Production N 2 O 4. 7 3. 9 <0. 01 1 0. 94 SF 6 from Magnesium Production SF 6 1. 7 3. 0 <0. 01 1 0. 95 several 0. 2 1. 3 <0. 01 1 0. 96 …… …… 1632. 1 1813. 6 0. 05 Emissions from Subs. for Ozone Depleting substances PFC, HFC & SF 6 Emissions from semicon. manuf. …… TOTAL …… 1. 00
Table 7. A 3. Source Category Analysis Summary (US Inventory) A IPCC Source Categories B Direct Greenhouse Gas C Key Source Category Flag D If Column C is Yes, Criteria for identification CO 2 Emissions from Stationary Combustion - Coal CO 2 Yes Level, Trend CO 2 Emissions from Stationary Combustion – Oil CO 2 Yes Level, Trend N 2 O Yes Trend ENERGY SECTOR …… INDUSTRIAL SECTOR N 2 O Emissions from Adipic Acid Production …… AGRICULTURE SECTOR …… E Comments
Qualitative Approaches to identify key source categories Criteria to consider that are not easily assessed through a quantitative analysis: Ø Ø Use of mitigation techniques and technologies Expecting high emission growth Categories with high uncertainty Exhibiting unexpectedly low or high emissions
Policy Relevance Ø GPG 2000 does not revise or replace the 96 GLs Ø Provides reference that complements and is consistent with the 96 GLs: ü specific source categories are the same or can be traced back to categories in 96 GLs ü uses same functional forms for the equations, or their equivalent ü allows for correction of any errors or deficiencies that have been identified in the 96 GLs
Conclusions Ø it is through good practice guidance and uncertainty management that a sound basis can be provided to produce more reliable estimates of the magnitude of absolute and trend uncertainties in GHG inventories than has been achieved previously Ø whatever the level of complexity of the inventory, good practice provides improved understanding of how uncertainties may be managed to produce emissions estimates that are acceptable for the purposes of the UNFCCC (i. e. transparency, consistency, comparability, completeness and accuracy in inventories), and for the scientific work associated with GHG inventories.
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