1. North Carolina Division of Air Quality
PART 3
Calculation Methods and Example Calculations for GHGs
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

2. Review: Industries/emission sources that emit GHGs
Combustion – boilers, turbines, engines, ovens, furnaces, kilns, incinerators
Including sorbents used in combustion control technology
Certain uses of miscellaneous carbonates (limestone/dolomite)
Anaerobic decomposition (landfills, manure management, anaerobic wastewater treatment)
Oil and natural gas production, transmission and distribution
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 2

3. Review: Industries/emission sources emit GHGs (cont’d)
Use of GHGs for as substitute for Ozone Depleting Substances , e.g.: refrigeration and air conditioning equipment, solvent cleaning, foam production, sterilization, fire extinguishing, and aerosols
Other very specific industrial processes – certain electronics manufacturing, mfg of specific petroleum products, metals, chemicals
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

4. North Carolina Division of Air Quality
Examples of Processes that don’t emit GHGs (but may emit volatile organic compounds and air toxics)
Coating processes
If you don’t use GHGs as the solvents
Combustion processes (drying ovens, thermal oxidizers) used in curing/drying do emit CO2, CH4, N20
Storage tanks
If you don’t store a product with dissolved methane in it
Refined products don’t contain dissolved methane
If you don’t have a flare or any other combustion
Applying/Curing polyester resins
If use combustion, then would emit
Reactors/Mixing vessels
If they don’t involve extra fuel or destruction of carbonates
If not used in “listed” industries (e.g., phosphoric acid, adipic acid, etc.)
Soy Crushing/Grain handling
If you don’t use GHGs for sterilization
Combustion/ anaerobic wastewater treatment do emit
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 4

5. Key Reference for Calculation Methods
2008 NC GHG Emission Inventory Instructions, Table 3
Provides links to DAQ guidance/spreadsheets and other references
When EPA rule is final, we will align calculation methods with those in EPA rule; can use either EPA or DAQ guidance for voluntary reporting
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 5

6. North Carolina Division of Air Quality
1641 Mail Service Center - Raleigh, NC   (919) 6

7. Calculation Methods In Table 3 Cover the following
Stationary Combustion (DAQ guidance/spreadsheets)
Refrigeration and Air Conditioning
Adipic Acid Production
Aluminum Production
Ammonia Production
Cement Production
Electricity Transmission and Distribution
HCFC-22 Production
Iron and Steel Production
Lime Production
Landfills
Pulp and Paper
Refrigeration and AC Equipment Manufacturing
Semiconductor Manufacturing
Oil and Natural Gas
Municipal Solid Waste Combustion
Soda Ash Consumption
Limestone and Dolomite Use
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

8. Additional Calculation Methods Provided in EPA’s Proposed Rule, not in Table 3
Electronics Manufacturing
Ethanol Production
Food Processing
Ferroalloy Production
Fluorinated Gas Production
Glass Production
HCFC-23 Destruction
Hydrogen Production
Lead Production
Magnesium Production
Manure Management Systems
Petrochemical Production
Phosphoric Acid Production
Silicon Carbide Production
Titanium Oxide Production
Underground Coal Mines
Wastewater Treatment (industrial)
Zinc Production
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

9. Industries Represented Today and their GHG emitting processes
Food/tobacco: combustion, wastewater, industrial landfill
Health/Education: combustion, R&D
Waste management: landfills, combustion
Coating/Furniture: combustion
Plastics/chemicals/resins/fibers (non-petrochemicals and assume not chemical on industry list): combustion
Pulp and paper: combustion, make-up carbonates, industrial landfills, wastewater
Natural gas transmission: fugitives (equip leaks), combustion
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

10. Focus Today on the Following Methods
Stationary source combustion
Landfills
Wastewater
Natural gas transmission & distribution
Pulp and paper
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

11. Stationary Source Combustion- the Universe is Large
EPA’s Proposed Rule Definition: “Produce electricity, steam, useful heat, or energy for industrial, commercial, or institutional use; or Reduce the volume of waste by removing combustible matter.”
Includes: boilers, turbines, internal combustion engines, incinerators, furnaces, ovens, kilns, burners, flares
More than 90% of NC Title V facilities have stationary source combustion sources
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 11

12. Stationary Source Combustion
Expected GHGs
Carbon Dioxide (CO2)
Methane (CH4)
Nitrous Oxide (N20)
Methodology: “Stationary Source Combustion Guidelines”
DAQ Spreadsheets available to assist in calculations (Utilizes DAQ methodology)
Can also use EPA proposed rule procedures, Subpart C, if you convert to tons
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 12

13. Stationary Source Combustion GHG Emission Estimation Methods
Direct Measurement via Continuous Emission Monitoring System (CEMS)
Calculation using Emission Factors (EFs)
Both Approaches used by DAQ and EPA proposed rule
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 13

14. North Carolina Division of Air Quality
CEMS Method
Two approaches for CO2 emissions
CO2 CEMS -report same as reported to satisfy Title IV requirements
O2 CEMS requires fuel analysis - report the same CO2 emissions as outlined in 40 CFR Part 75 Appendix G, Section 3
Can use CEMS to get heat input for use in emission factor calculations for CH4, N20
If CEMS applied to stack burning multiple fuels, separate out the emissions by fuel type and report in AERO under the appropriate operating scenario
CEMS may not account for all combustion emissions at facility - use calculation method for stacks without CEMS
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 14

15. Calculations using Emission Factors
Emissions = Activity Level x Emission Factor
Tons/yr
Quantity of Fuel Combusted
Tons Emitted / Gallon, ton, or ft3
For CO2
Activity Level: Based on quantity of fuel combusted
Emission Factor: Based on fuel carbon content and heating value
For CH4 and N2O
Emission Factor: Based on fuel type and combustor technology type
Emissions = Activity Level x Emission Factor
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 15

16. Stationary Source Combustion Calculation of CO2 - DAQ Approach
If you know either the Heat Content (Higher Heating Value or HHV) or Carbon Content of the Fuel
Tons/yr CO2 =
Fuel x Heat Content x Carbon Content x Oxidation Factor x x C
MWCO2
MWC
MMBtu per quantity of fuel
tons, or
Scf, or
gallons
kg C per MMBtu
1.0
44/12
1/907.2
Default Values in Table 1
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

17. Fuel Analysis Approach Fossil Fuel Combustion
Table 1. Emission Factors for Calculating CO2 Emissions –
Fuel Analysis Approach
Fuel Type
Heat Content
(Based on HHV)
Carbon Content
Fraction Oxidized
Fossil Fuel Combustion
Coal and Coke
MMBtu/ton
kg C/MMBtu
Anthracite Coal
25.09
28.26
1.00
Bituminous Coal
24.93
25.49
Sub-bituminous Coal
17.25
26.48
Lignite
14.21
26.30
Unspecified (residential/commercial)
22.05
26.00
Unspecified (industrial coking)
26.27
25.56
Unspecified (other industrial)
25.63
Unspecified (electric utility)
19.05
25.76
Coke
24.80
31.00
Natural Gas (by Higher Heating Value)
MMBtu/scf
,000 Btu/scf
,000 x 10-6
14.36
1, ,025 Btu/scf
1, ,025 x 10-6
14.43
1, ,050 Btu/scf
1, ,050 x 10-6
14.47
1, ,075 Btu/scf
1,050 – 1,075 x 10-6
14.58
1, ,100 Btu/scf
1,075 – 1,100 x 10-6
14.65
> 1,100 Btu/scf
> 1,100 x 10-6
14.92
U.S. Weighted Average (1,029 Btu/scf)
1,029 x 10-6
Petroleum Products
MMBtu/Barrel
Asphalt and Road Oil
6.636
20.62
Aviation Gasoline
5.048
18.87
Distillate Fuel Oil (#1, 2, and 4)
5.825
19.95
PART of
Table 1
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

18. Stationary Source Combustion Calculation of CO2 - DAQ Approach
If you don’t know either the Heat Content (HHV) or Carbon Content of the Fuel
Tons/yr CO2 = Fuel x Emission Factor x C
kg CO2/MMBtu, Or
Kg CO2/quantity of fuel
1/907.2
Table 2 contains Emission Factors
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 18

19. Table 2. Emission Factors for Calculating CO2 Emissions –
Generalized Approach
Fuel Type
CO2 Emission Factor (Per Unit Energy)
CO2 Emission Factor
(Per Unit mass or Volume)
Fossil Fuel Combustion
Coal and Coke
kg CO2/MMBtu
kg CO2/ton
Anthracite Coal
103.62
2,599.83
Bituminous Coal
93.46
2,330.04
Sub-bituminous Coal
97.09
1,674.86
Lignite
96.43
1,370.32
Unspecified (residential/commercial)
95.33
2,012.29
Unspecified (industrial coking)
93.72
2,462.12
Unspecified (other industrial)
93.98
2,072.19
Unspecified (electric utility)
94.45
1,884.53
Coke
113.67
2,818.93
Natural Gas (by Higher Heating Value)
kg CO2/scf
,000 Btu/scf
52.56
Varies
1, ,025 Btu/scf
52.91
1, ,050 Btu/scf
53.06
1, ,075 Btu/scf
53.46
1, ,100 Btu/scf
53.72
> 1,100 Btu/scf
54.71
U.S. Weighted Average (1,029 Btu/scf)
0.0546
Petroleum Products
kg CO2/gallon
Asphalt and Road Oil
75.61
11.95
Aviation Gasoline
69.19
8.32
Distillate Fuel Oil (#1, 2, and 4)
73.15
10.15
PART of
Table 2
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 19

20. North Carolina Division of Air Quality
Combustion Emission Estimation Methods For CH4 and N2O: Use Emission Factors
CH4 or N2O (tons/yr) =
= Fuel * Emission Factor * C1
MMBtu
g CH4/MMBtu, Or g N2O/MMBtu
1/907,200
Use EFs from Table 3 or Table 4
EFs from Table 3 are based on
Fuel type, sector, and configuration of device
EFs from Table 4 are based on
Fuel type and sector
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 20

21. North Carolina Division of Air Quality
Part of Table 3
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

22. North Carolina Division of Air Quality
All of
Table 4
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 22

23. What if Fuel isn’t in the Tables?
Options
EPA Subpart C table contains some additional fuels
Do you have source test?
Call us/or Regional Office contact
EXAMPLE: Saleable Animal Fat
EPA Subpart C has CO2 EF for Waste Oil in Table C-2 (kg CO2/mmBtu)
We found heat content from DAQ permit analysis: 124,586 Btu/gal
We just added fuels (like this) to DAQ’s tables
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

24. CH4 from Landfill Gas Flaring
DAQ provides method for CH4 due to incomplete combustion
Tons/yr CH4 =
Vol Flared x CH4 Vol Fraction x Residual CH4 x /2000
Lb/ft3 CH4
Lb/ton
ft3 of landfill gas
Can assume 0.5
1-destruction efficiency/100
Emissions from the actual combustion process are additional: compute using CH4 and N20 EFs
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

25. EPA Proposed Rule Calculation Approach Similar
For CO2, there are 3 calculation tiers:
Use fuel-specific carbon content (kg C per quantity of fuel)
Use fuel-specific HHV – use defaults for Emission Factor (kg CO2/MMBtu)
Heat content & fuel content measured on periodic basis (e.g., month)
Use defaults for HHV (MMBtu/quantity of fuel) and Emission Factor
For CH4 and N20, only 1 set of EFs (independent of device type)
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

26. Combustion Calculation Spreadsheets for DAQ Approach
Natural Gas boilers
Coal combustion
Fuel Oil Combustion (distillate & residual)
LPG Combustion - Liquefied Petroleum Gases Boilers
Wood Waste Combustion
Internal combustion - small gasoline and diesel engines
Internal Combustion – large gasoline and diesel engines
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 26

27. North Carolina Division of Air Quality
1020 BTU/ SCF
21.16 Million SCF (actual yearly)
14.43 KG/ MMBtu and Fraction Oxidized = 1
(Table 1)
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 27

28. North Carolina Division of Air Quality
1641 Mail Service Center - Raleigh, NC   (919) 28

29. Output screen continued
GREENHOUSE GAS POLLUTANT
ACTUAL EMISSIONS
Emission Factor
(AFTER CONTROLS / LIMITS)
tons/yr
lb/MMBtu
Carbon Dioxide
116.64
Methane
2.14E-02
1.98E-03
Nitrous oxide
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 29

30. Computing GHGs from Thermal Oxidizers That Destroy VOC?
Can use spreadsheet to calculate CO2, CH4 and N2O from the fossil fuel used
A few options for the solvent combustion
Are stack test results readily available
Can you estimate the carbon content?
EPA has an EF for “solvent” in [kg/MMBtu], you will need Higher Heating Value
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

31. QA/QC of Combustion Results
For combustion, CO2 >> CH4 and N20
Check units – need short tons (tons) per year- NOT metric tons (tonnes)
If site-specific fuel parameters used, check against Table 1 values
Btu content of fuel (remember, we use higher heating value--HHV)
Carbon content
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 31

32. North Carolina Division of Air Quality
Landfills
2nd largest CH4 source in the U.S. in 2006
Dozen or more Title V Municipal Solid Waste landfills
Industrial Landfills use similar approach
Expected GHGs
CH4
CO2 and N2O (if on-site combustion)
DAQ references “EPA Climate Leaders” document (2004)
EPA proposed rule (subpart HH) has similar methodology
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

33. Landfill Guidance Addresses CH4 emissions from 2 Cases
No landfill gas collection systems
With landfill gas recovery and control systems
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

34. Landfills – no recovery
Use “Landfill Gas Emissions Model” (LandGEM) to compute CH4 generated
Compute emissions as follows:
CH4 emissions =
CH4 generated *(1 – oxidation factor)
Oxidation factor accounts for amount of CH4 oxidized while passing through landfill cover; 10% is default (factor=0.1)
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919) 34

35. Example Landfill calculation
Landgem Model Inputs
(see , section 3, for additional default values that can be used)
Landfill Specific
Waste disposal = 80,000 Mg annual tonnage of MSW for each filling year
Year opened 1982
Current Year: 2003
Capacity: 2,400,000 Mg
Can use Defaults (more defaults available in Users Guide):
Lo (generation potential) = AP-42 default (100 m3/Mg)
k (rate constant) = AP-42 default (arid 0.02/yr; non-arid 0.04/yr)
Methane concentration = 50% by volume (default)

36. Example Landfill Calculation (cnt’d)
LandGEM Model output: For the year 2003, CH4 generated = tonnes/yr
Assume 10% oxidation factor (default)
Therefore, CH4 Emissions = 1850 tonnes/yr * (1-0.1) = 1660 tonnes/yr
Convert to short tons for AERO:
1660 tonnes/yr * tons/tonnes
= 1830 tons CH4/yr
which is more than 25,000 metric tons CO2e
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

37. Landfill with Collection/Recovery (use only for the part of the Landfill with collection)
CH4 Emissions =
CH4 Collected
Colleff
- CH4 Collected
*(1 – OF)
+ (CH4 Collected * Vent)
where:
CH4 Collected = CH4 Collected by active gas collection system (should have measurement of this)
Colleff = collection system efficiency (Can use 0.75 as default)
OF = oxidation fraction (use 0.10 as a default)
Vent = fraction vented (Can use 0.01 to account for startup/shutdown/malfunction)

38. Example Landfill Calculation with Collection
Is in the reference.
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

39. EPA proposed rule differences
EPA proposed rule requires that you calculate generated CH4 (whether or not you have recovery) – eqn same as 3.01 version of LandGEM model
If you have collection/recovery:
Measure recovered LFG and other parameters
Calculate emissions based on amt generated minus recovered (account for oxidation and destruction efficiency), and
Calculate emissions based on collection efficiency
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

40. North Carolina Division of Air Quality
Wastewater
DAQ doesn’t reference an approach in Table 3
Use the approach in the EPA proposed rule -subpart II
Addresses CH4 resulting from anaerobic wastewater treatment; separate equation for anaerobic digester
Aerobic treatment doesn’t emit CH4
Amount of CH4 generated based on “Chemical Oxygen Demand” (COD) of wastewater
COD is a widely used parameter of organic pollution in industrial wastewater. It is a measure of the capacity of water to consume oxygen during the decomposition of organic matter and the oxidation of inorganic chemicals such as ammonia and nitrite. The basis for the COD test is that nearly all organic compounds can be fully oxidized to carbon dioxide with a strong oxidizing agent under acidic conditions.
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

41. Wastewater CH4 – EPA proposed rule, subpart II
CH4 (industrial wastewater) =
Where:
CH4 = Annual CH4 mass emissions from the wastewater
treatment system (metric tons)
Flow = Monthly flow treated through anaerobic treatment system (m3/month)
COD = Average monthly value for chemical oxygen demand of wastewater entering anaerobic treatment systems other than digesters (kg/m3)
Bo = Maximum CH4 producing potential of industrial wastewater
(default value of 0.25 kg CH4 /kg COD)
MCF = CH4 correction factor, indicating the extent to which the organic content (measured as COD) degrades anaerobically. DEFAULT values provided in Table II-1, based on lagoon type and system design.

42. Pulp and Paper DAQ references the “GHG PROTOCOL INITIATIVE”
(you must register to download)
Document: Calculation Tools for Estimating Greenhouse Gas Emissions for Pulp and Paper Mills (version 1.1, July 2005)
Excel Workbook: ICFPA/NCASI Spreadsheets for Calculating GHG emissions from pulp and paper manufacturing (version 1.3)
Copyright: Portions of the spreadsheets and associated materials were developed by WRI, WBCSD or NCASI, are copyrighted, and are published here with the permission of those developers. The User acknowledges these copyrights.

43. Pulp and Paper Workbook
Can skip the Combustion Operations sheet (use DAQ guidance)
Other P&P Sheets of interest
Direct - Make-up Carbonates: CO2 from make-up carbonates used in the pulp mill
Waste Mngmt: CH4 from mill-owned landfills or anaerobic treatment operations
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

44. Pulp and Paper – can also use Subpart AA EPA rule
Chemical recovery furnaces at kraft and soda mills (inc. those that burn spent pulping liquor)
Chemical recovery combustion units at sulfite facilities
Pulp mill lime kilns at kraft and soda facilities
Systems for adding make up chemicals (CaCO3, Na2CO3)
Other onsite combustion (subpart C)
Onsite landfills (subpart HH)
On-site watewater treatment (subpart II)
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

45. Natural Gas Transmission and Distribution
DAQ Provides Reference – work done by Calif.
Addresses CH4 emitted from fugitives (CO2 may also be emitted if gas stream has it and via oxidation)
Non-routine activities (Upsets/ equipment venting)
Equipment leaks (valves, flanges)
Relies on API compendium (2004) and Interstate Natural Gas Association of America (INGAA) Guidelines (2005)
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

46. Natural Gas Transmission and Distribution (cont’d)
EPA’s Proposed rule provides calculation methods (subpart W)
Note not all emission points are included – the Technical Support Document discusses this further
EPA’s proposed rule also requires suppliers to report (Subpart NN)
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

47. North Carolina Division of Air Quality
Need Help?
If you are unsure if your sources emit GHGs or need help calculating, contact the appropriate Regional Office or Central Office
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)

48. Part 3 Discussion/Questions
North Carolina Division of Air Quality 
1641 Mail Service Center - Raleigh, NC   (919)