Outline of Course

1. CGE Greenhouse Gas Inventory Hands-on Training Workshopfor the African Region- Energy Sector –CombustionPretoria, South Africa18-22 September 2006

2. Outline of Course • Fuel combustion (Today) • References • Basic Emission Processes • Methodologies • Relationships with other sources and sectors • Uncertainty • Quality control and completeness

3. Outline of Course (continued) • Fugitives (Tomorrow) • References • Coal mining and handling • Oil and natural gas systems • Data issues

4. Survey says…? Audience poll… • Who has prepared a national inventory for your country? • Who has worked on the Energy Sector? • Please share your… • Problems you have faced with preparing estimates for the Energy Sector • Plans for the future to improve your inventory

5. Reference materials • UNFCCC (COP decisions, reporting guidelines, etc.) • IPCC • Revised 1996 IPCC Guidelines • Good Practice Guidance • Emission Factor Database (EFDB) • IPCC WG I Assessment Reports • Use “old” SAR GWP values for reporting • International Energy Agency

6. IPCC Guidance • Fundamental methods laid out in 1996 Revised Guidelines • IPCC Good Practice clarifies some issues (e.g., international bunker fuels) and provides some updated factors… • …but no significant changes made for fuel combustion! • 2006 IPCC Guidelines provides new information on Non-Energy Use, new Tier 2 method for oil systems fugitives, & guidance on abandoned coal mines

7. Key Category Analysis • Level assessment based on share of total national emissions for each source category • Trend assessment based on contribution of category to changes in emission trends • Qualitative criteria

8. Key Category Analysis • Idea of key sources based on a measure of which sources contribute to uncertainty in inventory • Most if not all source categories in the Energy Sector will be Key Source Categories • Analysis only as good as original emissions data. • You probably already know your key categories.

9. Energy SectorFuel Combustion Emissions

10. African GHG Emissions (Top 20)

11. Stationary Sources • Energy Industries • extraction, production and transformation • electricity generation, petroleum refining • autoproduction of electricity • Manufacturing Industries and Construction • iron and steel production • non-ferrous metal production • chemical manufacturing • pulp, paper and print • food processing, beverages and tobacco • Commercial/Institutional • Residential • Agriculture/Forestry/Fisheries

12. Autoproducers

13. Mobile Sources • Civil Aviation • Road Transportation • Cars • Light duty trucks • Heavy duty trucks and buses • Motorcycles • Railways • Navigation • International Bunker Fuels are reported separately

14. Carbon dioxide (CO2) emissions • Methodology is mass balance-based • Oxidation of the carbon in fuels during combustion • In perfect combustion conditions, total carbon content of fuels would be converted to CO2 • Real combustion processes result in small amounts of partially oxidized and unoxidized carbon

15. Carbon Flow for a typical Combustion Process • Most carbon is emitted as CO2 immediately • Small fraction emitted as non-CO2 gases • CH4, CO, NMVOCs • Ultimately oxidizes to CO2 in the atmosphere • Integrated into overall calculation of CO2 emissions • Remaining part of the fuel carbon is unburned • Assumed to remain as solid (ash and soot) • Account by using oxidation factors

16. Non-CO2 emissions • Direct greenhouse gases • Methane (CH4) • Nitrous oxide (N2O) • Precursors and SO2 • Nitrogen oxides (NOx) • Carbon monoxide (CO) • Non-methane volatile organic compounds (NMVOCs) • Sulfur dioxide (SO2)

17. Non-CO2 requires detailed process information • Combustion conditions • Size and vintage of the combustion technology • Maintenance • Operational practices • Emission controls • Fuel characteristics

18. Methane (CH4) • Emissions a function of: • methane content of the fuel • hydrocarbons passing unburnt through engine • engine type • post-combustion controls • Depends on temperature in boiler/kiln/stove • Highest emissions in residential applications (e.g., small stoves, open biomass burning, charcoal production)

19. Nitrous Oxide (N2O) • Lower combustion temperatures tend to lead to higher N2O emissions • Emission controls (catalysts) on vehicles can increase the rate of N2O generation, depending on: • driving practices (i.e., number of cold starts) • type and age of the catalyst • Significant emissions for countries with a high penetration of vehicles with catalysts http://unfccc.int/resource/docs/2004/sbsta/inf03.pdf

20. Methods for CO2 • ‘Reference Approach’ (Tier 1) • estimates based on national energy balance (production + imports - exports) by fuel type without information on activities • performed quickly if basic energy balance sheet is available • way of cross-checking emission estimates of CO2 with the Sectoral Approach • ‘Sectoral Approach’ (Tier 1) • Estimates based on fuel consumption data by sectoral activity • ‘Bottom-Up Approaches’ (Tier 2 or 3) • More detailed activity and fuel data

21. Fundamental Equation

22. Six basic steps • Collect fuel consumption data • Convert fuel data to a common energy unit • Select carbon content factors for each fossil fuel/product type and estimate the total carbon content of fuels consumed • Subtract the amount of carbon stored in products for long periods of time • Multiply by an oxidation factor • Convert carbon to full molecular weight of CO2 and sum across all fuels

23. 1. Consumption Data • Reference Approach: • Estimate apparent consumption of fuels within the country • Sectoral Approach: • Collect actual consumption statistics by fuel type and economic sector • Tier 2 or 3: • Collect actual fuel consumption statistics by fuel type, economic sector, and combustion technology type

24. Data Collection Issues • IPCC sectoral approach can still be used even if energy data are not collected using same sector categories • focus on completeness and use judgment or proxy data to allocate to various subsectors • Biomass combustion not needed for CO2, but reported for information purposes • Informal sector fuel use is important issue if not captured in energy statistics • household kerosene use can be approximated based on expert judgment or proxy data

25. 2. Common Energy Unit • Convert fuel data to a common energy unit • Production and consumption of solid and liquid fuels in tons • Gaseous fuels in cubic meters • Original units converted into energy units using calorific values (i.e., heating values) • Reference approach: use different calorific values for production, imports, and exports • Calorific values used should be reported

26. 3. Estimate total carbon content of fuels consumed Natural Gas • Depends on composition (methane, ethane, propane, butane, and heavier hydrocarbons) • Natural gas flared at the production site will usually be "wet“ - its carbon content factor will be different • Typical: 15 to 17 tons C/TJ Oil • Lower carbon content for light refined petroleum products such as gasoline • Higher for heavier products such as residual fuel oil • Typical for crude oil is 20 ton C/TJ Coal • Depend on coal's rank and composition of hydrogen, sulfur, ash, oxygen, and nitrogen • Typical ranges from 25 to 28 ton C/TJ

27. 4. Subtract non-energy uses • Oil refineries: asphalt and bitumen for road construction, naphthas, lubricants, and plastics • Natural gas: for ammonia production • Liquid petroleum gas (LPG): solvents and synthetic rubber • Coking: metals industry Attempt to use country-specific data instead of IPCC default carbon storage factors.

28. 5. Oxidation Factor • Multiply by an oxidation factor to account for the small amount of unoxidized carbon that is left in ash or soot. • Amount of carbon remaining unoxidized should be low for oil and natural gas combustion… • …but can be larger and more variable for coal combustion • When national oxidation factors are not available, use IPCC default factors

29. Oxidation Factor Values Natural Gas • Less than 1 percent left unburned • Remains as soot in the burner, stack, or environment • IPCC default oxidation factor = 99.5% • Higher for flares in the oil and gas industry • Closer to 100% for efficient turbines Oil • 1.5 ± 1 percent left unburned • IPCC default oxidation factor = 99% • Recent research has shown 100% in autos

30. Oxidation Factor Values (cont.) Coal • Range from 0.6 to 6.6 percent unburned • Primarily in the form of bottom and fly ash • IPCC default oxidation factor = 98% Biomass • Can range widely, especially for open combustion • For closed combustion (e.g., boiler) range from 1 to 10 percent • No IPCC default

31. 6. Convert to full molecular weight and sum • Convert carbon to full molecular weight of CO2 and summation across all fuels • To express the results as carbon dioxide (CO2), multiply the quantity of carbon oxidized by the molecular weight ratio of CO2 to C (44:12)

32. International Bunker Fuels • CO2 emissions arising from fuels used in ships or aircraft for international transport not be included in the national total • Fuels delivered to and consumed by international bunkers should be subtracted from the fuel supply to the country • Bunker fuel emissions should be mentioned in a separate table as a memo item • See IPCC decision trees on marine and aviation transport emission allocation

33. Biomass Fuels • CO2 emissions should not be included in national emission totals from fuel combustion • Reported for information only… • household fuelwood • ethanol & biodiesel for transport • Account for mixed fuels (e.g., ethanol blends) • Net CO2 emissions implicitly accounted for under the Land Use Change and Forestry Sector • Non-CO2 emissions from biomass combustion should be estimated and reported under the Energy Sector!

34. Methods for Non-CO2 emissions Tier 1 • Multiply fuel consumed by an average emission factor • Do not require detailed activity data • Rely on widely available fuel supply data that assume an average combustion technology is used Tiers 2/3 • Multiply fuel consumed by detailed fuel type and technology-specific emission factors • Tier 2 methods use data that is disaggregated according to technology types • Tier 3 methods estimate emissions according to activity types (km traveled or ton-km carried) and specific fuel efficiency or fuel rates Use most disaggregated technology-specific and country-specific emission factors available

35. Fundamental Equation Emissions = Σ(Emission Factorabc • Fuel Consumptionabc) Where, a = fuel type b = sector activity c = technology type including emissions controls

36. Stationary Combustion • Default emission factors for CH4, N2O, NOx, CO, & NMVOCs by major technology and fuel types are presented in the IPCC Guidelines • Most notable: CH4 emissions from open burning and biomass combustion • Charcoal production is likely to produce methane emissions at a rate that is several orders of magnitude greater other combustion processes

37. Mobile Combustion • Major transport activity (road, air, rail, and ships) • Most notable: N2O emissions from road transportation, affected by the type of emission control technologies • Non-Annex I countries should focus their efforts on collecting data on the number of vehicles with catalytic emissions control devices that operate in their country

38. Mobile combustion (cont.) • Road transport activity data • assume vast majority of motor gasoline used for transport • Check data with equipment counts or vehicle sales/import/export data • Base assumptions of vehicle type and emission control technology on vehicle vintage data (i.e., model year of sale) and assumed activity level (i.e., vkt/vehicle) • Consider national emission standards, leaded gasoline prevalence, and compliance with standards

39. Relationships with Other Sources and Sectors • Industrial Processes Sector • non-energy fossil fuel feedstocks data, if available, may not be reliable • petrochemical “feedstocks” may actually be used for energy • coal purchased by iron and steel industry may be used to make coke • focus on petrochemical industry and metal production (e.g., iron and steel) • conservative estimate: Assume plastics, asphalt, and some lubricants stored • subtract carbon content from these products

40. Relationships with Other Sources and Sectors (cont.) • Waste Sector • combustion of wastes for energy purposes included in Energy Sector • incineration of plastics • Land-Use Change and Forestry Sector • biomass carbon implicitly accounted for • Autoproduction of electricity • Fuel use for military purposes • Mobile sources in Agriculture

41. Quality control and completeness checks • All gases (CO2, CH4, and N2O) • All source and sub-source categories • All national territories addressed • Bunker fuels and military operations • All fossil fuel fired electric power stations • Blast furnaces and coke production • Waste combustion with energy recovery • Black market fuels • Non-metered fuel use for pipelines by compressor stations

42. Uncertainty • Uncertainty in carbon content and calorific values for fuels is related to the variability in fuel composition and frequency of actual measurements. Likely to be small for all countries. • For most non-Annex I countries, the uncertainty in activity data (i.e., fuel consumption data) will the dominant issue! • effort should focus on collection of fuel consumption data • country-specific carbon content factors are unlikely to improve CO2 estimates significantly • It is important to document the likely causes of uncertainty and discuss steps taken to reduce uncertainties.

43. IPCC Software and reporting tables • Software to aid in preparation of greenhouse gas inventories • Provides IPCC default (i.e., Tier 1) methods • National factors can be used where available