Good

1. 1A.1
CGE
Greenhouse Gas Inventory
Hands-on Training Workshop
Energy Sector

2. 1A.2
Our goal

3. 1A.3
Our goal
To gain knowledge, comprehension, or mastery through experience or study.
Pronunciation: shuey si

4. 1A.4
Outline of course
 Fuel combustion
 References
 Basic emission processes
 Methodologies
 Relationships with other sources and sectors
 Uncertainty
 Quality control and completeness

5. 1A.5
Outline of course (continued)
 Fugitives
 References
 Coal mining and handling
 Oil and natural gas systems
 Data issues

6. 1A.6
Survey says…?
Audience poll…
 Who has prepared a national inventory for your
country?
 Who has worked on the Energy Sector?
 Please share…
 Problems you have faced in preparing estimates for the
Energy Sector
 Your plans for the future to improve your inventory

7. 1A.7
Reference materials
 UNFCCC (COP decisions, reporting guidelines,
etc.)
 IPCC
 Revised 1996 IPCC Guidelines
 IPCC Good Practice Guidance
 Emission Factor Database (EFDB)
 IPCC Working Group I Assessment Reports
 Use “old” Second Assessment Report (SAR)
Global Warming Potential (GWP) values for
reporting
 International Energy Agency

8. 1A.8
IPCC guidance
 Fundamental methods laid out in 1996 Revised
Guidelines
 IPCC good practice guidance clarifies some
issues (e.g. international bunker fuels) and
provides some updated factors…
 …but no major changes made for fuel
combustion!
 2006 IPCC Guidelines will provide new
information on Non-Energy Use, new Tier 2
method for oil systems fugitives, guidance on
abandoned coal mines

9. 1A.9
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

10. 1A.10
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

11. 1A.11
Energy Sector –
Fuel Combustion
Emissions

12. 1A.12
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

13. 1A.13
Autoproducers
Note: p. 1.32 of the IPCC Guidelines, Reference Manual - Volume 3

14. 1A.14
Mobile sources
 Civil Aviation
 Road Transportation
 Cars
 Light duty trucks
 Heavy duty trucks and buses
 Motorcycles
 Railways
 Navigation
 International Bunker Fuels are reported separately

15. 1A.15
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

16. 1A.16
Carbon flow for a typical
combustion process
 Most carbon is emitted as CO2 immediately
 Small fraction emitted as non-CO2 gases
 CH4, CO, non-methane volatile organic compounds
(NMVOCs)
 Ultimately oxidizes to CO2 in the atmosphere
 Integrated into overall calculation of CO2 emissions
 Each carbon atom has two atmospheric lifetimes
 Remaining part of the fuel carbon is unburnt
 Assumed to remain as solid (ash and soot)
 Account by using oxidation factors

17. 1A.17
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)

18. 1A.18
Require detailed
process information
 Combustion conditions
 Size and vintage of the combustion
technology
 Maintenance
 Operational practices
 Emission controls
 Fuel characteristics

19. 1A.19
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)

20. 1A.20
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

21. 1A.21
Methods for estimating 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

22. 1A.22
Fundamental equation

23. 1A.23
Six basic steps
1. Collect fuel consumption data
2. Convert fuel data to a common energy unit
3. Select carbon content factors for each fossil
fuel/product type and estimate the total
carbon content of fuels consumed
4. Subtract the amount of carbon stored in
products for long periods of time
5. Multiply by an oxidation factor
6. Convert carbon to full molecular weight of
CO2 and sum across all fuels

24. 1A.24
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

25. 1A.25
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 judgement or proxy
data to allocate to various subsectors
 Biomass combustion not needed for CO2 estimation,
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 judgement or proxy data

26. 1A.26
2. Common energy unit
 Convert fuel data to a common energy unit
 Production and consumption of solid and
liquid fuels in tonnes
 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

27. 1A.27
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 tonnes 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 tonnes C/TJ
Coal
 Depend on coal's rank and composition of hydrogen, sulfur,
ash, oxygen and nitrogen
 Typical ranges from 25 to 28 tonnes C/TJ

28. 1A.28
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.

29. 1A.29
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

30. 1A.30
Oxidation factor values
Natural gas
 Less than 1% left unburnt
 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 per cent left unburnt
 IPCC default oxidation factor = 99%
 Recent research has shown 100% in autos

31. 1A.31
Coal
 Range from 0.6% to 6.6% unburnt
 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), the range
is from 1% to 10%
 No IPCC default
Oxidation factor values (cont.)

32. 1A.32
6. Convert to full molecular
weight and sum
 Convert carbon to full molecular weight of
CO2 and add across all fuels
 To express the results as CO2, multiply the
quantity of carbon oxidized by the molecular
weight ratio of CO2 to C (44:12)

33. 1A.33
International bunker fuels
 CO2 emissions arising from fuels used in
ships or aircraft for international transport,
not to 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

34. 1A.34
Biomass fuels
 CO2 emissions from biomass fuels 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!

35. 1A.35
Methods for non-CO2
emissions
Tier 1
 Multiply fuel consumed by an average emission factor
 Does 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 are disaggregated according to
technology types
 Tier 3 methods estimate emissions according to activity
types (km traveled or tonne-km carried) and specific fuel
efficiency or fuel rates
Use most disaggregated technology-specific and country-specific
emission factors available

36. 1A.36
Fundamental equation
Emissions =
Σ(Emission Factorabc • Fuel Consumptionabc)
Where,
a = fuel type
b = sector activity
c = technology type including emissions controls

37. 1A.37
Stationary combustion
 Default emission factors for CH4, N2O, NOx,
CO and NMVOCs by major technology and
fuel type 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 than from other
combustion processes

38. 1A.38
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 Parties should focus their
efforts on collecting data on the number of
vehicles with catalytic emissions control
devices that operate in their country

39. 1A.39
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

40. 1A.40
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

41. 1A.41
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

42. 1A.42
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

43. 1A.43
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 Parties the uncertainty in
activity data (i.e. fuel consumption data) will be 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.

44. 1A.44
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